1fetchmail(1) fetchmail reference manual fetchmail(1)
2
6 fetchmail - fetch mail from a POP, IMAP, ETRN, or ODMR-capable server
7
10 fetchmail [option...] [mailserver...]
11 fetchmailconf
12
15 fetchmail is a mail-retrieval and forwarding utility; it fetches mail
16 from remote mailservers and forwards it to your local (client)
17 machine's delivery system. You can then handle the retrieved mail
18 using normal mail user agents such as mutt(1), elm(1) or Mail(1). The
19 fetchmail utility can be run in a daemon mode to repeatedly poll one or
20 more systems at a specified interval.
21 The fetchmail program can gather mail from servers supporting any of
23 the common mail-retrieval protocols: POP2 (legacy, to be removed from
24 future release), POP3, IMAP2bis, IMAP4, and IMAP4rev1. It can also use
25 the ESMTP ETRN extension and ODMR. (The RFCs describing all these pro‐
26 tocols are listed at the end of this manual page.)
27 While fetchmail is primarily intended to be used over on-demand TCP/IP
29 links (such as SLIP or PPP connections), it may also be useful as a
30 message transfer agent for sites which refuse for security reasons to
31 permit (sender-initiated) SMTP transactions with sendmail.
32 SUPPORT, TROUBLESHOOTING
35 For troubleshooting, tracing and debugging, you need to increase fetch‐
36 mail's verbosity to actually see what happens. To do that, please run
37 both of the two following commands, adding all of the options you'd
38 normally use.
39 env LC_ALL=C fetchmail -V -v --nodetach --nosyslog
42 (This command line prints in English how fetchmail understands
44 your configuration.)
45 env LC_ALL=C fetchmail -vvv --nodetach --nosyslog
48 (This command line actually runs fetchmail with verbose English
50 output.)
51 Also see item #G3 in fetchmail's FAQ ⟨https://fetchmail.sourceforge.io/
53 fetchmail-FAQ.html#G3⟩
54 You can omit the LC_ALL=C part above if you want output in the local
56 language (if supported). However if you are posting to mailing lists,
57 please leave it in. The maintainers do not necessarily understand your
58 language, please use English.
59 CONCEPTS
64 If fetchmail is used with a POP or an IMAP server (but not with ETRN or
65 ODMR), it has two fundamental modes of operation for each user account
66 from which it retrieves mail: singledrop- and multidrop-mode.
67 In singledrop-mode,
69 fetchmail assumes that all messages in the user's account (mail‐
70 box) are intended for a single recipient. The identity of the
71 recipient will either default to the local user currently exe‐
72 cuting fetchmail, or will need to be explicitly specified in the
73 configuration file.
74 fetchmail uses singledrop-mode when the fetchmailrc configura‐
76 tion contains at most a single local user specification for a
77 given server account.
78 In multidrop-mode,
80 fetchmail assumes that the mail server account actually contains
81 mail intended for any number of different recipients. There‐
82 fore, fetchmail must attempt to deduce the proper "envelope
83 recipient" from the mail headers of each message. In this mode
84 of operation, fetchmail almost resembles a mail transfer agent
85 (MTA).
86 Note that neither the POP nor IMAP protocols were intended for
88 use in this fashion, and hence envelope information is often not
89 directly available. The ISP must stores the envelope informa‐
90 tion in some message header and. The ISP must also store one
91 copy of the message per recipient. If either of the conditions
92 is not fulfilled, this process is unreliable, because fetchmail
93 must then resort to guessing the true envelope recipient(s) of a
94 message. This usually fails for mailing list messages and Bcc:d
95 mail, or mail for multiple recipients in your domain.
96 fetchmail uses multidrop-mode when more than one local user
98 and/or a wildcard is specified for a particular server account
99 in the configuration file.
100 In ETRN and ODMR modes,
102 these considerations do not apply, as these protocols are based
103 on SMTP, which provides explicit envelope recipient information.
104 These protocols always support multiple recipients.
105 As each message is retrieved, fetchmail normally delivers it via SMTP
107 to port 25 on the machine it is running on (localhost), just as though
108 it were being passed in over a normal TCP/IP link. fetchmail provides
109 the SMTP server with an envelope recipient derived in the manner
110 described previously. The mail will then be delivered according to
111 your MTA's rules (the Mail Transfer Agent is usually sendmail(8),
112 exim(8), or postfix(8)). Invoking your system's MDA (Mail Delivery
113 Agent) is the duty of your MTA. All the delivery-control mechanisms
114 (such as .forward files) normally available through your system MTA and
115 local delivery agents will therefore be applied as usual.
116 If your fetchmail configuration sets a local MDA (see the --mda
118 option), it will be used directly instead of talking SMTP to port 25.
119 If the program fetchmailconf is available, it will assist you in set‐
121 ting up and editing a fetchmailrc configuration. It runs under the X
122 window system and requires that the language Python and the Tk toolkit
123 (with Python bindings) be present on your system. If you are first
124 setting up fetchmail for single-user mode, it is recommended that you
125 use Novice mode. Expert mode provides complete control of fetchmail
126 configuration, including the multidrop features. In either case, the
127 'Autoprobe' button will tell you the most capable protocol a given
128 mailserver supports, and warn you of potential problems with that
129 server.
130
133 Fetchmail's run-time strings have been translated (localized) to some
134 languages, but the manual is only available in English. In some situa‐
135 tions, for comparing output to manual, it may be helpful to switch
136 fetchmail to English output by overriding the locale variables, for
137 instance:
138 env LC_ALL=C fetchmail # add other options before the hash
141 env LANG=en fetchmail # other options before the hash
144 or similar. Details vary by operating system.
146
149 The behavior of fetchmail is controlled by command-line options and a
150 run control file, ~/.fetchmailrc, the syntax of which we describe in a
151 later section (this file is what the fetchmailconf program edits).
152 Command-line options override ~/.fetchmailrc declarations.
153 Each server name that you specify following the options on the command
155 line will be queried. If you do not specify any servers on the command
156 line, each 'poll' entry in your ~/.fetchmailrc file will be queried,
157 unless the idle option is used, which see.
158 To facilitate the use of fetchmail in scripts and pipelines, it returns
160 an appropriate exit code upon termination -- see EXIT CODES below.
161 The following options modify the behavior of fetchmail. It is seldom
163 necessary to specify any of these once you have a working .fetchmailrc
164 file set up.
165 Almost all options have a corresponding keyword which can be used to
167 declare them in a .fetchmailrc file.
168 Some special options are not covered here, but are documented instead
170 in sections on AUTHENTICATION and DAEMON MODE which follow.
171 General Options
173 -? | --help
174 Displays option help.
175 -V | --version
177 Displays the version information for your copy of fetchmail. No
178 mail fetch is performed. Instead, for each server specified,
179 all the option information that would be computed if fetchmail
180 were connecting to that server is displayed. Any non-printables
181 in passwords or other string names are shown as backslashed C-
182 like escape sequences. This option is useful for verifying that
183 your options are set the way you want them.
184 -c | --check
186 Return a status code to indicate whether there is mail waiting,
187 without actually fetching or deleting mail (see EXIT CODES
188 below). This option turns off daemon mode (in which it would be
189 useless). It doesn't play well with queries to multiple sites,
190 and doesn't work with ETRN or ODMR. It will return a false pos‐
191 itive if you leave read but undeleted mail in your server mail‐
192 box and your fetch protocol can't tell kept messages from new
193 ones. This means it will work with IMAP, not work with POP2,
194 and may occasionally flake out under POP3.
195 -s | --silent
197 Silent mode. Suppresses all progress/status messages that are
198 normally echoed to standard output during a fetch (but does not
199 suppress actual error messages). The --verbose option overrides
200 this.
201 -v | --verbose
203 Verbose mode. All control messages passed between fetchmail and
204 the mailserver are echoed to stdout. Overrides --silent. Dou‐
205 bling this option (-v -v) causes extra diagnostic information to
206 be printed.
207 --nosoftbounce
209 (since v6.3.10, Keyword: set no softbounce, since v6.3.10)
210 Hard bounce mode. All permanent delivery errors cause messages
211 to be deleted from the upstream server, see "no softbounce"
212 below.
213 --softbounce
215 (since v6.3.10, Keyword: set softbounce, since v6.3.10)
216 Soft bounce mode. All permanent delivery errors cause messages
217 to be left on the upstream server if the protocol supports that.
218 This option is on by default to match historic fetchmail docu‐
219 mentation, and will be changed to hard bounce mode in the next
220 fetchmail release.
221 Disposal Options
223 -a | --all | (since v6.3.3) --fetchall
224 (Keyword: fetchall, since v3.0)
225 Retrieve both old (seen) and new messages from the mailserver.
226 The default is to fetch only messages the server has not marked
227 seen. Under POP3, this option also forces the use of RETR
228 rather than TOP. Note that POP2 retrieval behaves as though
229 --all is always on (see RETRIEVAL FAILURE MODES below) and this
230 option does not work with ETRN or ODMR. While the -a and --all
231 command-line and fetchall rcfile options have been supported for
232 a long time, the --fetchall command-line option was added in
233 v6.3.3.
234 -k | --keep
236 (Keyword: keep)
237 Keep retrieved messages on the remote mailserver. Normally,
238 messages are deleted from the folder on the mailserver after
239 they have been retrieved. Specifying the keep option causes
240 retrieved messages to remain in your folder on the mailserver.
241 This option does not work with ETRN or ODMR. If used with POP3,
242 it is recommended to also specify the --uidl option or uidl key‐
243 word.
244 -K | --nokeep
246 (Keyword: nokeep)
247 Delete retrieved messages from the remote mailserver. This
248 option forces retrieved mail to be deleted. It may be useful if
249 you have specified a default of keep in your .fetchmailrc. This
250 option is forced on with ETRN and ODMR.
251 -F | --flush
253 (Keyword: flush)
254 POP3/IMAP only. This is a dangerous option and can cause mail
255 loss when used improperly. It deletes old (seen) messages from
256 the mailserver before retrieving new messages. Warning: This
257 can cause mail loss if you check your mail with other clients
258 than fetchmail, and cause fetchmail to delete a message it had
259 never fetched before. It can also cause mail loss if the mail
260 server marks the message seen after retrieval (IMAP2 servers).
261 You should probably not use this option in your configuration
262 file. If you use it with POP3, you must use the 'uidl' option.
263 What you probably want is the default setting: if you don't
264 specify '-k', then fetchmail will automatically delete messages
265 after successful delivery.
266 --limitflush
268 POP3/IMAP only, since version 6.3.0. Delete oversized messages
269 from the mailserver before retrieving new messages. The size
270 limit should be separately specified with the --limit option.
271 This option does not work with ETRN or ODMR.
272 Protocol and Query Options
274 -p <proto> | --proto <proto> | --protocol <proto>
275 (Keyword: proto[col])
276 Specify the protocol to use when communicating with the remote
277 mailserver. If no protocol is specified, the default is AUTO.
278 proto may be one of the following:
279 AUTO Tries IMAP, POP3, and POP2 (skipping any of these for
281 which support has not been compiled in).
282 POP2 Post Office Protocol 2 (legacy, to be removed from future
284 release)
285 POP3 Post Office Protocol 3
287 APOP Use POP3 with old-fashioned MD5-challenge authentication.
289 Considered not resistant to man-in-the-middle attacks.
290 RPOP Use POP3 with RPOP authentication.
292 KPOP Use POP3 with Kerberos V4 authentication on port 1109.
294 SDPS Use POP3 with Demon Internet's SDPS extensions.
296 IMAP IMAP2bis, IMAP4, or IMAP4rev1 (fetchmail automatically
298 detects their capabilities).
299 ETRN Use the ESMTP ETRN option.
301 ODMR Use the the On-Demand Mail Relay ESMTP profile.
303 All these alternatives work in basically the same way (communicating
305 with standard server daemons to fetch mail already delivered to a mail‐
306 box on the server) except ETRN and ODMR. The ETRN mode allows you to
307 ask a compliant ESMTP server (such as BSD sendmail at release 8.8.0 or
308 higher) to immediately open a sender-SMTP connection to your client
309 machine and begin forwarding any items addressed to your client machine
310 in the server's queue of undelivered mail. The ODMR mode requires an
311 ODMR-capable server and works similarly to ETRN, except that it does
312 not require the client machine to have a static DNS.
313 -U | --uidl
315 (Keyword: uidl)
316 Force UIDL use (effective only with POP3). Force client-side
317 tracking of 'newness' of messages (UIDL stands for "unique ID
318 listing" and is described in RFC1939). Use with 'keep' to use a
319 mailbox as a baby news drop for a group of users. The fact that
320 seen messages are skipped is logged, unless error logging is
321 done through syslog while running in daemon mode. Note that
322 fetchmail may automatically enable this option depending on
323 upstream server capabilities. Note also that this option may be
324 removed and forced enabled in a future fetchmail version. See
325 also: --idfile.
326 --idle (since 6.3.3)
328 (Keyword: idle, since before 6.0.0)
329 Enable IDLE use (effective only with IMAP). Note that this works
330 with only one account and one folder at a given time, other
331 folders or accounts will not be polled when idle is in effect!
332 While the idle rcfile keyword had been supported for a long
333 time, the --idle command-line option was added in version 6.3.3.
334 IDLE use means that fetchmail tells the IMAP server to send
335 notice of new messages, so they can be retrieved sooner than
336 would be possible with regular polls.
337 -P <portnumber> | --service <servicename>
339 (Keyword: service) Since version 6.3.0.
340 The service option permits you to specify a service name to con‐
341 nect to. You can specify a decimal port number here, if your
342 services database lacks the required service-port assignments.
343 See the FAQ item R12 and the --ssl documentation for details.
344 This replaces the older --port option.
345 --port <portnumber>
347 (Keyword: port)
348 Obsolete version of --service that does not take service names.
349 Note: this option may be removed from a future version.
350 --principal <principal>
352 (Keyword: principal)
353 The principal option permits you to specify a service principal
354 for mutual authentication. This is applicable to POP3 or IMAP
355 with Kerberos 4 authentication only. It does not apply to Ker‐
356 beros 5 or GSSAPI. This option may be removed in a future
357 fetchmail version.
358 -t <seconds> | --timeout <seconds>
360 (Keyword: timeout)
361 The timeout option allows you to set a server-nonresponse time‐
362 out in seconds. If a mailserver does not send a greeting mes‐
363 sage or respond to commands for the given number of seconds,
364 fetchmail will drop the connection to it. Without such a time‐
365 out fetchmail might hang until the TCP connection times out,
366 trying to fetch mail from a down host, which may be very long.
367 This would be particularly annoying for a fetchmail running in
368 the background. There is a default timeout which fetchmail -V
369 will report. If a given connection receives too many timeouts
370 in succession, fetchmail will consider it wedged and stop retry‐
371 ing. The calling user will be notified by email if this hap‐
372 pens.
373 Beginning with fetchmail 6.3.10, the SMTP client uses the recom‐
375 mended minimum timeouts from RFC-5321 while waiting for the
376 SMTP/LMTP server it is talking to. You can raise the timeouts
377 even more, but you cannot shorten them. This is to avoid a
378 painful situation where fetchmail has been configured with a
379 short timeout (a minute or less), ships a long message (many
380 MBytes) to the local MTA, which then takes longer than timeout
381 to respond "OK", which it eventually will; that would mean the
382 mail gets delivered properly, but fetchmail cannot notice it and
383 will thus refetch this big message over and over again.
384 --plugin <command>
386 (Keyword: plugin)
387 The plugin option allows you to use an external program to
388 establish the TCP connection. This is useful if you want to use
389 ssh, or need some special firewalling setup. The program will
390 be looked up in $PATH and can optionally be passed the hostname
391 and port as arguments using "%h" and "%p" respectively (note
392 that the interpolation logic is rather primitive, and these
393 tokens must be bounded by whitespace or beginning of string or
394 end of string). Fetchmail will write to the plugin's stdin and
395 read from the plugin's stdout.
396 --plugout <command>
398 (Keyword: plugout)
399 Identical to the plugin option above, but this one is used for
400 the SMTP connections.
401 -r <name> | --folder <name>
403 (Keyword: folder[s])
404 Causes a specified non-default mail folder on the mailserver (or
405 comma-separated list of folders) to be retrieved. The syntax of
406 the folder name is server-dependent. This option is not avail‐
407 able under POP3, ETRN, or ODMR.
408 --tracepolls
410 (Keyword: tracepolls)
411 Tell fetchmail to poll trace information in the form 'polling
412 account %s' and 'folder %s' to the Received line it generates,
413 where the %s parts are replaced by the user's remote name, the
414 poll label, and the folder (mailbox) where available (the
415 Received header also normally includes the server's true name).
416 This can be used to facilitate mail filtering based on the
417 account it is being received from. The folder information is
418 written only since version 6.3.4.
419 --ssl (Keyword: ssl)
421 Causes the connection to the mail server to be encrypted via
422 SSL, by negotiating SSL directly after connecting (SSL-wrapped
423 mode). Please see the description of --sslproto below! More
424 information is available in the README.SSL file that ships with
425 fetchmail.
426 Note that even if this option is omitted, fetchmail may still
428 negotiate SSL in-band for POP3 or IMAP, through the STLS or
429 STARTTLS feature. You can use the --sslproto option to modify
430 that behavior.
431 If no port is specified, the connection is attempted to the well
433 known port of the SSL version of the base protocol. This is
434 generally a different port than the port used by the base proto‐
435 col. For IMAP, this is port 143 for the clear protocol and port
436 993 for the SSL secured protocol; for POP3, it is port 110 for
437 the clear text and port 995 for the encrypted variant.
438 If your system lacks the corresponding entries from /etc/ser‐
440 vices, see the --service option and specify the numeric port
441 number as given in the previous paragraph (unless your ISP had
442 directed you to different ports, which is uncommon however).
443 --sslcert <name>
445 (Keyword: sslcert)
446 For certificate-based client authentication. Some SSL encrypted
447 servers require client side keys and certificates for authenti‐
448 cation. In most cases, this is optional. This specifies the
449 location of the public key certificate to be presented to the
450 server at the time the SSL session is established. It is not
451 required (but may be provided) if the server does not require
452 it. It may be the same file as the private key (combined key
453 and certificate file) but this is not recommended. Also see
454 --sslkey below.
455 NOTE: If you use client authentication, the user name is fetched
457 from the certificate's CommonName and overrides the name set
458 with --user.
459 --sslkey <name>
461 (Keyword: sslkey)
462 Specifies the file name of the client side private SSL key.
463 Some SSL encrypted servers require client side keys and certifi‐
464 cates for authentication. In most cases, this is optional.
465 This specifies the location of the private key used to sign
466 transactions with the server at the time the SSL session is
467 established. It is not required (but may be provided) if the
468 server does not require it. It may be the same file as the pub‐
469 lic key (combined key and certificate file) but this is not rec‐
470 ommended.
471 If a password is required to unlock the key, it will be prompted
473 for at the time just prior to establishing the session to the
474 server. This can cause some complications in daemon mode.
475 Also see --sslcert above.
477 --sslproto <value>
479 (Keyword: sslproto, NOTE: semantic changes since v6.4.0)
480 This option has a dual use, out of historic fetchmail behaviour.
481 It controls both the SSL/TLS protocol version and, if --ssl is
482 not specified, the STARTTLS behaviour (upgrading the protocol to
483 an SSL or TLS connection in-band). Some other options may how‐
484 ever make TLS mandatory.
485 Only if this option and --ssl are both missing for a poll, there will
487 be opportunistic TLS for POP3 and IMAP, where fetchmail will attempt to
488 upgrade to TLSv1 or newer.
489 Recognized values for --sslproto are given below. You should normally
491 chose one of the auto-negotiating options, i. e. 'auto' or one of the
492 options ending in a plus (+) character. Note that depending on OpenSSL
493 library version and configuration, some options cause run-time errors
494 because the requested SSL or TLS versions are not supported by the par‐
495 ticular installed OpenSSL library.
496 '', the empty string
498 Disable STARTTLS. If --ssl is given for the same server,
499 log an error and pretend that 'auto' had been used
500 instead.
501 'auto' (default). Since v6.4.0. Require TLS. Auto-negotiate
503 TLSv1 or newer, disable SSLv3 downgrade. (fetchmail
504 6.3.26 and older have auto-negotiated all protocols that
505 their OpenSSL library supported, including the broken
506 SSLv3).
507 'SSL23'
509 see 'auto'.
510 'SSL3' Require SSLv3 exactly. SSLv3 is broken, not supported on
512 all systems, avoid it if possible. This will make fetch‐
513 mail negotiate SSLv3 only, and is the only way besides
514 'SSL3+' to have fetchmail 6.4.0 or newer permit SSLv3.
515 'SSL3+'
517 same as 'auto', but permit SSLv3 as well. This is the
518 only way besides 'SSL3' to have fetchmail 6.4.0 or newer
519 permit SSLv3.
520 'TLS1' Require TLSv1. This does not negotiate TLSv1.1 or newer,
522 and is discouraged. Replace by TLS1+ unless the latter
523 chokes your server.
524 'TLS1+'
526 Since v6.4.0. See 'auto'.
527 'TLS1.1'
529 Since v6.4.0. Require TLS v1.1 exactly.
530 'TLS1.1+'
532 Since v6.4.0. Require TLS. Auto-negotiate TLSv1.1 or
533 newer.
534 'TLS1.2'
536 Since v6.4.0. Require TLS v1.2 exactly.
537 'TLS1.2+'
539 Since v6.4.0. Require TLS. Auto-negotiate TLSv1.2 or
540 newer.
541 'TLS1.3'
543 Since v6.4.0. Require TLS v1.3 exactly.
544 'TLS1.3+'
546 Since v6.4.0. Require TLS. Auto-negotiate TLSv1.3 or
547 newer.
548 Unrecognized parameters
550 are treated the same as 'auto'.
551 NOTE: you should hardly ever need to use anything other than ''
553 (to force an unencrypted connection) or 'auto' (to enforce TLS).
554 --sslcertck
556 (Keyword: sslcertck, default enabled since v6.4.0)
557 --sslcertck causes fetchmail to require that SSL/TLS be used and
558 disconnect if it can not successfully negotiate SSL or TLS, or
559 if it cannot successfully verify and validate the certificate
560 and follow it to a trust anchor (or trusted root certificate).
561 The trust anchors are given as a set of local trusted certifi‐
562 cates (see the sslcertfile and sslcertpath options). If the
563 server certificate cannot be obtained or is not signed by one of
564 the trusted ones (directly or indirectly), fetchmail will dis‐
565 connect, regardless of the sslfingerprint option.
566 Note that CRL (certificate revocation lists) are only supported
568 in OpenSSL 0.9.7 and newer! Your system clock should also be
569 reasonably accurate when using this option.
570 --nosslcertck
572 (Keyword: no sslcertck, only in v6.4.X)
573 The opposite of --sslcertck, this is a discouraged option. It
574 permits fetchmail to continue connecting even if the server cer‐
575 tificate failed the verification checks. Should only be used
576 together with --sslfingerprint.
577 --sslcertfile <file>
579 (Keyword: sslcertfile, since v6.3.17)
580 Sets the file fetchmail uses to look up local certificates. The
581 default is empty. This can be given in addition to --sslcert‐
582 path below, and certificates specified in --sslcertfile will be
583 processed before those in --sslcertpath. The option can be used
584 in addition to --sslcertpath.
585 The file is a text file. It contains the concatenation of
587 trusted CA certificates in PEM format.
588 Note that using this option will suppress loading the default
590 SSL trusted CA certificates file unless you set the environment
591 variable FETCHMAIL_INCLUDE_DEFAULT_X509_CA_CERTS to a non-empty
592 value.
593 --sslcertpath <directory>
595 (Keyword: sslcertpath)
596 Sets the directory fetchmail uses to look up local certificates.
597 The default is your OpenSSL default directory. The directory
598 must be hashed the way OpenSSL expects it - every time you add
599 or modify a certificate in the directory, you need to use the
600 c_rehash tool (which comes with OpenSSL in the tools/ subdirec‐
601 tory). Also, after OpenSSL upgrades, you may need to run
602 c_rehash; particularly when upgrading from 0.9.X to 1.0.0.
603 This can be given in addition to --sslcertfile above, which see
605 for precedence rules.
606 Note that using this option will suppress adding the default SSL
608 trusted CA certificates directory unless you set the environment
609 variable FETCHMAIL_INCLUDE_DEFAULT_X509_CA_CERTS to a non-empty
610 value.
611 --sslcommonname <common name>
613 (Keyword: sslcommonname; since v6.3.9)
614 Use of this option is discouraged. Before using it, contact the
615 administrator of your upstream server and ask for a proper SSL
616 certificate to be used. If that cannot be attained, this option
617 can be used to specify the name (CommonName) that fetchmail
618 expects on the server certificate. A correctly configured
619 server will have this set to the hostname by which it is
620 reached, and by default fetchmail will expect as much. Use this
621 option when the CommonName is set to some other value, to avoid
622 the "Server CommonName mismatch" warning, and only if the
623 upstream server can't be made to use proper certificates.
624 --sslfingerprint <fingerprint>
626 (Keyword: sslfingerprint)
627 Specify the fingerprint of the server key (an MD5 hash of the
628 key) in hexadecimal notation with colons separating groups of
629 two digits. The letter hex digits must be in upper case. This is
630 the format that fetchmail uses to report the fingerprint when an
631 SSL connection is established. When this is specified, fetchmail
632 will compare the server key fingerprint with the given one, and
633 the connection will fail if they do not match, regardless of the
634 sslcertck setting. The connection will also fail if fetchmail
635 cannot obtain an SSL certificate from the server. This can be
636 used to prevent man-in-the-middle attacks, but the finger print
637 from the server must be obtained or verified over a secure chan‐
638 nel, and certainly not over the same Internet connection that
639 fetchmail would use.
640 Using this option will prevent printing certificate verification
642 errors as long as --nosslcertck is in effect.
643 To obtain the fingerprint of a certificate stored in the file
645 cert.pem, try:
646 openssl x509 -in cert.pem -noout -md5 -fingerprint
648 For details, see x509(1ssl).
650 Delivery Control Options
652 -S <hosts> | --smtphost <hosts>
653 (Keyword: smtp[host])
654 Specify a hunt list of hosts to forward mail to (one or more
655 hostnames, comma-separated). Hosts are tried in list order; the
656 first one that is up becomes the forwarding target for the cur‐
657 rent run. If this option is not specified, 'localhost' is used
658 as the default. Each hostname may have a port number following
659 the host name. The port number is separated from the host name
660 by a slash; the default port is "smtp". If you specify an abso‐
661 lute path name (beginning with a /), it will be interpreted as
662 the name of a UNIX socket accepting LMTP connections (such as is
663 supported by the Cyrus IMAP daemon) Example:
664 --smtphost server1,server2/2525,server3,/var/imap/socket/lmtp
666 This option can be used with ODMR, and will make fetchmail a
668 relay between the ODMR server and SMTP or LMTP receiver.
669 WARNING: if you use address numeric IP addresses here, be sure
671 to use --smtpaddress or --smtpname (either of which see) with a
672 valid SMTP address literal!
673 --fetchdomains <hosts>
675 (Keyword: fetchdomains)
676 In ETRN or ODMR mode, this option specifies the list of domains
677 the server should ship mail for once the connection is turned
678 around. The default is the FQDN of the machine running fetch‐
679 mail.
680 -D <domain> | --smtpaddress <domain>
682 (Keyword: smtpaddress)
683 Specify the domain to be appended to addresses in RCPT TO lines
684 shipped to SMTP. When this is not specified, the name of the
685 SMTP server (as specified by --smtphost) is used for SMTP/LMTP
686 and 'localhost' is used for UNIX socket/BSMTP.
687 NOTE: if you intend to use numeric addresses, or so-called
689 address literals per the SMTP standard, write them in proper
690 SMTP syntax, for instance --smtpaddress "[192.0.2.6]" or --smt‐
691 paddress "[IPv6:2001:DB8::6]".
692 --smtpname <user@domain>
694 (Keyword: smtpname)
695 Specify the domain and user to be put in RCPT TO lines shipped
696 to SMTP. The default user is the current local user. Please
697 also see the NOTE about --smtpaddress and address literals
698 above.
699 -Z <nnn> | --antispam <nnn[, nnn]...>
701 (Keyword: antispam)
702 Specifies the list of numeric SMTP errors that are to be inter‐
703 preted as a spam-block response from the listener. A value of
704 -1 disables this option. For the command-line option, the list
705 values should be comma-separated. Note that the antispam values
706 only apply to "MAIL FROM" responses in the SMTP/LMTP dialogue,
707 but several MTAs (Postfix in its default configuration, qmail)
708 defer the anti-spam response code until after the RCPT TO.
709 --antispam does not work in these circumstances. Also see
710 --softbounce (default) and its inverse.
711 -m <command> | --mda <command>
713 (Keyword: mda)
714 This option lets fetchmail use a Message or Local Delivery Agent
715 (MDA or LDA) directly, rather than forward via SMTP or LMTP.
716 To avoid losing mail, use this option only with MDAs like mail‐
718 drop or MTAs like sendmail that exit with a nonzero status on
719 disk-full and other delivery errors; the nonzero status tells
720 fetchmail that delivery failed and prevents the message from
721 being deleted on the server.
722 If fetchmail is running as root, it sets its user id while
724 delivering mail through an MDA as follows: First, the FETCH‐
725 MAILUSER, LOGNAME, and USER environment variables are checked in
726 this order. The value of the first variable from his list that
727 is defined (even if it is empty!) is looked up in the system
728 user database. If none of the variables is defined, fetchmail
729 will use the real user id it was started with. If one of the
730 variables was defined, but the user stated there isn't found,
731 fetchmail continues running as root, without checking remaining
732 variables on the list. Practically, this means that if you run
733 fetchmail as root (not recommended), it is most useful to define
734 the FETCHMAILUSER environment variable to set the user that the
735 MDA should run as. Some MDAs (such as maildrop) are designed to
736 be setuid root and setuid to the recipient's user id, so you
737 don't lose functionality this way even when running fetchmail as
738 unprivileged user. Check the MDA's manual for details.
739 Some possible MDAs are "/usr/sbin/sendmail -i -f %F -- %T"
741 (Note: some several older or vendor sendmail versions mistake --
742 for an address, rather than an indicator to mark the end of the
743 option arguments), "/usr/bin/deliver" and "/usr/bin/maildrop -d
744 %T". Local delivery addresses will be inserted into the MDA
745 command wherever you place a %T; the mail message's From address
746 will be inserted where you place an %F.
747 Do NOT enclose the %F or %T string in single quotes! For both
749 %T and %F, fetchmail encloses the addresses in single quotes
750 ('), after removing any single quotes they may contain, before
751 the MDA command is passed to the shell.
752 Do NOT use an MDA invocation that dispatches on the contents of
754 To/Cc/Bcc, like "sendmail -i -t" or "qmail-inject", it will cre‐
755 ate mail loops and bring the just wrath of many postmasters down
756 upon your head. This is one of the most frequent configuration
757 errors!
758 Also, do not try to combine multidrop mode with an MDA such as
760 maildrop that can only accept one address, unless your upstream
761 stores one copy of the message per recipient and transports the
762 envelope recipient in a header; you will lose mail.
763 The well-known procmail(1) package is very hard to configure
765 properly, it has a very nasty "fall through to the next rule"
766 behavior on delivery errors (even temporary ones, such as out of
767 disk space if another user's mail daemon copies the mailbox
768 around to purge old messages), so your mail will end up in the
769 wrong mailbox sooner or later. The proper procmail configuration
770 is outside the scope of this document. Using maildrop(1) is usu‐
771 ally much easier, and many users find the filter syntax used by
772 maildrop easier to understand.
773 Finally, we strongly advise that you do not use qmail-inject.
775 The command line interface is non-standard without providing
776 benefits for typical use, and fetchmail makes no attempts to
777 accommodate qmail-inject's deviations from the standard. Some of
778 qmail-inject's command-line and environment options are actually
779 dangerous and can cause broken threads, non-detected duplicate
780 messages and forwarding loops.
781 --lmtp (Keyword: lmtp)
784 Cause delivery via LMTP (Local Mail Transfer Protocol). A ser‐
785 vice host and port must be explicitly specified on each host in
786 the smtphost hunt list (see above) if this option is selected;
787 the default port 25 will (in accordance with RFC 2033) not be
788 accepted.
789 --bsmtp <filename>
791 (Keyword: bsmtp)
792 Append fetched mail to a BSMTP file. This simply contains the
793 SMTP commands that would normally be generated by fetchmail when
794 passing mail to an SMTP listener daemon.
795 An argument of '-' causes the SMTP batch to be written to stan‐
797 dard output, which is of limited use: this only makes sense for
798 debugging, because fetchmail's regular output is interspersed on
799 the same channel, so this isn't suitable for mail delivery. This
800 special mode may be removed in a later release.
801 Note that fetchmail's reconstruction of MAIL FROM and RCPT TO
803 lines is not guaranteed correct; the caveats discussed under THE
804 USE AND ABUSE OF MULTIDROP MAILBOXES below apply. This mode has
805 precedence before --mda and SMTP/LMTP.
806 --bad-header {reject|accept}
808 (Keyword: bad-header; since v6.3.15)
809 Specify how fetchmail is supposed to treat messages with bad
810 headers, i. e. headers with bad syntax. Traditionally, fetchmail
811 has rejected such messages, but some distributors modified
812 fetchmail to accept them. You can now configure fetchmail's be‐
813 haviour per server.
814 Resource Limit Control Options
817 -l <maxbytes> | --limit <maxbytes>
818 (Keyword: limit)
819 Takes a maximum octet size argument, where 0 is the default and
820 also the special value designating "no limit". If nonzero, mes‐
821 sages larger than this size will not be fetched and will be left
822 on the server (in foreground sessions, the progress messages
823 will note that they are "oversized"). If the fetch protocol
824 permits (in particular, under IMAP or POP3 without the fetchall
825 option) the message will not be marked seen.
826 An explicit --limit of 0 overrides any limits set in your run
828 control file. This option is intended for those needing to
829 strictly control fetch time due to expensive and variable phone
830 rates.
831 Combined with --limitflush, it can be used to delete oversized
833 messages waiting on a server. In daemon mode, oversize notifi‐
834 cations are mailed to the calling user (see the --warnings
835 option). This option does not work with ETRN or ODMR.
836 -w <interval> | --warnings <interval>
838 (Keyword: warnings)
839 Takes an interval in seconds. When you call fetchmail with a
840 'limit' option in daemon mode, this controls the interval at
841 which warnings about oversized messages are mailed to the call‐
842 ing user (or the user specified by the 'postmaster' option).
843 One such notification is always mailed at the end of the the
844 first poll that the oversized message is detected. Thereafter,
845 re-notification is suppressed until after the warning interval
846 elapses (it will take place at the end of the first following
847 poll).
848 -b <count> | --batchlimit <count>
850 (Keyword: batchlimit)
851 Specify the maximum number of messages that will be shipped to
852 an SMTP listener before the connection is deliberately torn down
853 and rebuilt (defaults to 0, meaning no limit). An explicit
854 --batchlimit of 0 overrides any limits set in your run control
855 file. While sendmail(8) normally initiates delivery of a mes‐
856 sage immediately after receiving the message terminator, some
857 SMTP listeners are not so prompt. MTAs like smail(8) may wait
858 till the delivery socket is shut down to deliver. This may pro‐
859 duce annoying delays when fetchmail is processing very large
860 batches. Setting the batch limit to some nonzero size will pre‐
861 vent these delays. This option does not work with ETRN or ODMR.
862 -B <number> | --fetchlimit <number>
864 (Keyword: fetchlimit)
865 Limit the number of messages accepted from a given server in a
866 single poll. By default there is no limit. An explicit --fetch‐
867 limit of 0 overrides any limits set in your run control file.
868 This option does not work with ETRN or ODMR.
869 --fetchsizelimit <number>
871 (Keyword: fetchsizelimit)
872 Limit the number of sizes of messages accepted from a given
873 server in a single transaction. This option is useful in reduc‐
874 ing the delay in downloading the first mail when there are too
875 many mails in the mailbox. By default, the limit is 100. If
876 set to 0, sizes of all messages are downloaded at the start.
877 This option does not work with ETRN or ODMR. For POP3, the only
878 valid non-zero value is 1.
879 --fastuidl <number>
881 (Keyword: fastuidl)
882 Do a binary instead of linear search for the first unseen UID.
883 Binary search avoids downloading the UIDs of all mails. This
884 saves time (especially in daemon mode) where downloading the
885 same set of UIDs in each poll is a waste of bandwidth. The num‐
886 ber 'n' indicates how rarely a linear search should be done. In
887 daemon mode, linear search is used once followed by binary
888 searches in 'n-1' polls if 'n' is greater than 1; binary search
889 is always used if 'n' is 1; linear search is always used if 'n'
890 is 0. In non-daemon mode, binary search is used if 'n' is 1;
891 otherwise linear search is used. The default value of 'n' is 4.
892 This option works with POP3 only.
893 -e <count> | --expunge <count>
895 (Keyword: expunge)
896 Arrange for deletions to be made final after a given number of
897 messages. Under POP2 or POP3, fetchmail cannot make deletions
898 final without sending QUIT and ending the session -- with this
899 option on, fetchmail will break a long mail retrieval session
900 into multiple sub-sessions, sending QUIT after each sub-session.
901 This is a good defense against line drops on POP3 servers.
902 Under IMAP, fetchmail normally issues an EXPUNGE command after
903 each deletion in order to force the deletion to be done immedi‐
904 ately. This is safest when your connection to the server is
905 flaky and expensive, as it avoids resending duplicate mail after
906 a line hit. However, on large mailboxes the overhead of re-
907 indexing after every message can slam the server pretty hard, so
908 if your connection is reliable it is good to do expunges less
909 frequently. Also note that some servers enforce a delay of a
910 few seconds after each quit, so fetchmail may not be able to get
911 back in immediately after an expunge -- you may see "lock busy"
912 errors if this happens. If you specify this option to an integer
913 N, it tells fetchmail to only issue expunges on every Nth
914 delete. An argument of zero suppresses expunges entirely (so no
915 expunges at all will be done until the end of run). This option
916 does not work with ETRN or ODMR.
917 Authentication Options
920 -u <name> | --user <name> | --username <name>
921 (Keyword: user[name])
922 Specifies the user identification to be used when logging in to
923 the mailserver. The appropriate user identification is both
924 server and user-dependent. The default is your login name on
925 the client machine that is running fetchmail. See USER AUTHEN‐
926 TICATION below for a complete description.
927 -I <specification> | --interface <specification>
929 (Keyword: interface)
930 Require that a specific interface device be up and have a spe‐
931 cific local or remote IPv4 (IPv6 is not supported by this option
932 yet) address (or range) before polling. Frequently fetchmail is
933 used over a transient point-to-point TCP/IP link established
934 directly to a mailserver via SLIP or PPP. That is a relatively
935 secure channel. But when other TCP/IP routes to the mailserver
936 exist (e.g. when the link is connected to an alternate ISP),
937 your username and password may be vulnerable to snooping (espe‐
938 cially when daemon mode automatically polls for mail, shipping a
939 clear password over the net at predictable intervals). The
940 --interface option may be used to prevent this. When the speci‐
941 fied link is not up or is not connected to a matching IP
942 address, polling will be skipped. The format is:
943 interface/iii.iii.iii.iii[/mmm.mmm.mmm.mmm]
945 The field before the first slash is the interface name (i.e.
947 sl0, ppp0 etc.). The field before the second slash is the
948 acceptable IP address. The field after the second slash is a
949 mask which specifies a range of IP addresses to accept. If no
950 mask is present 255.255.255.255 is assumed (i.e. an exact
951 match). This option is currently only supported under Linux and
952 FreeBSD. Please see the monitor section for below for FreeBSD
953 specific information.
954 Note that this option may be removed from a future fetchmail
956 version.
957 -M <interface> | --monitor <interface>
959 (Keyword: monitor)
960 Daemon mode can cause transient links which are automatically
961 taken down after a period of inactivity (e.g. PPP links) to
962 remain up indefinitely. This option identifies a system TCP/IP
963 interface to be monitored for activity. After each poll inter‐
964 val, if the link is up but no other activity has occurred on the
965 link, then the poll will be skipped. However, when fetchmail is
966 woken up by a signal, the monitor check is skipped and the poll
967 goes through unconditionally. This option is currently only
968 supported under Linux and FreeBSD. For the monitor and inter‐
969 face options to work for non root users under FreeBSD, the
970 fetchmail binary must be installed SGID kmem. This would be a
971 security hole, but fetchmail runs with the effective GID set to
972 that of the kmem group only when interface data is being col‐
973 lected.
974 Note that this option may be removed from a future fetchmail
976 version.
977 --auth <type>
979 (Keyword: auth[enticate])
980 This option permits you to specify an authentication type (see
981 USER AUTHENTICATION below for details). The possible values are
982 any, password, kerberos_v5, kerberos (or, for excruciating
983 exactness, kerberos_v4), gssapi, cram-md5, otp, ntlm, msn (only
984 for POP3), external (only IMAP) and ssh. When any (the default)
985 is specified, fetchmail tries first methods that don't require a
986 password (EXTERNAL, GSSAPI, KERBEROS IV, KERBEROS 5); then it
987 looks for methods that mask your password (CRAM-MD5, NTLM, X-OTP
988 - note that MSN is only supported for POP3, but not autoprobed);
989 and only if the server doesn't support any of those will it ship
990 your password en clair. Other values may be used to force vari‐
991 ous authentication methods (ssh suppresses authentication and is
992 thus useful for IMAP PREAUTH). (external suppresses authentica‐
993 tion and is thus useful for IMAP EXTERNAL). Any value other
994 than password, cram-md5, ntlm, msn or otp suppresses fetchmail's
995 normal inquiry for a password. Specify ssh when you are using
996 an end-to-end secure connection such as an ssh tunnel; specify
997 external when you use TLS with client authentication and specify
998 gssapi or kerberos_v4 if you are using a protocol variant that
999 employs GSSAPI or K4. Choosing KPOP protocol automatically
1000 selects Kerberos authentication. This option does not work with
1001 ETRN. GSSAPI service names are in line with RFC-2743 and IANA
1002 registrations, see Generic Security Service Application Program
1003 Interface (GSSAPI)/Kerberos/Simple Authentication and Security
1004 Layer (SASL) Service Names ⟨https://www.iana.org/assignments/
1005 gssapi-service-names/⟩.
1006 Miscellaneous Options
1008 -f <pathname> | --fetchmailrc <pathname>
1009 Specify a non-default name for the ~/.fetchmailrc run control
1010 file. The pathname argument must be either "-" (a single dash,
1011 meaning to read the configuration from standard input) or a
1012 filename. Unless the --version option is also on, a named file
1013 argument must have permissions no more open than 0700
1014 (u=rwx,g=,o=) or else be /dev/null.
1015 -i <pathname> | --idfile <pathname>
1017 (Keyword: idfile)
1018 Specify an alternate name for the .fetchids file used to save
1019 message UIDs. NOTE: since fetchmail 6.3.0, write access to the
1020 directory containing the idfile is required, as fetchmail writes
1021 a temporary file and renames it into the place of the real
1022 idfile only if the temporary file has been written successfully.
1023 This avoids the truncation of idfiles when running out of disk
1024 space.
1025 --pidfile <pathname>
1027 (Keyword: pidfile; since fetchmail v6.3.4)
1028 Override the default location of the PID file that is used as a
1029 lock file. Default: see "ENVIRONMENT" below. Note that many
1030 places in the code and documentation, the term "lock file" is
1031 used. This file contains the process ID of the running fetch‐
1032 mail on the first line and potentially the daemon interval on a
1033 second line.
1034 -n | --norewrite
1036 (Keyword: no rewrite)
1037 Normally, fetchmail edits RFC-822 address headers (To, From, Cc,
1038 Bcc, and Reply-To) in fetched mail so that any mail IDs local to
1039 the server are expanded to full addresses (@ and the mailserver
1040 hostname are appended). This enables replies on the client to
1041 get addressed correctly (otherwise your mailer might think they
1042 should be addressed to local users on the client machine!).
1043 This option disables the rewrite. (This option is provided to
1044 pacify people who are paranoid about having an MTA edit mail
1045 headers and want to know they can prevent it, but it is gener‐
1046 ally not a good idea to actually turn off rewrite.) When using
1047 ETRN or ODMR, the rewrite option is ineffective.
1048 -E <line> | --envelope <line>
1050 (Keyword: envelope; Multidrop only)
1051 In the configuration file, an enhanced syntax is used:
1052 envelope [<count>] <line>
1053 This option changes the header fetchmail assumes will carry a
1055 copy of the mail's envelope address. Normally this is 'X-Enve‐
1056 lope-To'. Other typically found headers to carry envelope
1057 information are 'X-Original-To' and 'Delivered-To'. Now, since
1058 these headers are not standardized, practice varies. See the
1059 discussion of multidrop address handling below. As a special
1060 case, 'envelope "Received"' enables parsing of sendmail-style
1061 Received lines. This is the default, but discouraged because it
1062 is not fully reliable.
1063 Note that fetchmail expects the Received-line to be in a spe‐
1065 cific format: It must contain "by host for address", where host
1066 must match one of the mailserver names that fetchmail recognizes
1067 for the account in question.
1068 The optional count argument (only available in the configuration
1070 file) determines how many header lines of this kind are skipped.
1071 A count of 1 means: skip the first, take the second. A count of
1072 2 means: skip the first and second, take the third, and so on.
1073 -Q <prefix> | --qvirtual <prefix>
1075 (Keyword: qvirtual; Multidrop only)
1076 The string prefix assigned to this option will be removed from
1077 the user name found in the header specified with the envelope
1078 option (before doing multidrop name mapping or localdomain
1079 checking, if either is applicable). This option is useful if you
1080 are using fetchmail to collect the mail for an entire domain and
1081 your ISP (or your mail redirection provider) is using qmail.
1082 One of the basic features of qmail is the Delivered-To: message
1083 header. Whenever qmail delivers a message to a local mailbox it
1084 puts the username and hostname of the envelope recipient on this
1085 line. The major reason for this is to prevent mail loops. To
1086 set up qmail to batch mail for a disconnected site the ISP-mail‐
1087 host will have normally put that site in its 'Virtualhosts' con‐
1088 trol file so it will add a prefix to all mail addresses for this
1089 site. This results in mail sent to 'username@userhost.user‐
1090 dom.dom.com' having a Delivered-To: line of the form:
1091 Delivered-To: mbox-userstr-username@userhost.example.com
1093 The ISP can make the 'mbox-userstr-' prefix anything they choose
1095 but a string matching the user host name is likely. By using
1096 the option 'envelope Delivered-To:' you can make fetchmail reli‐
1097 ably identify the original envelope recipient, but you have to
1098 strip the 'mbox-userstr-' prefix to deliver to the correct user.
1099 This is what this option is for.
1100 --configdump
1102 Parse the ~/.fetchmailrc file, interpret any command-line
1103 options specified, and dump a configuration report to standard
1104 output. The configuration report is a data structure assignment
1105 in the language Python. This option is meant to be used with an
1106 interactive ~/.fetchmailrc editor like fetchmailconf, written in
1107 Python.
1108 -y | --yydebug
1110 Enables parser debugging, this option is meant to be used by
1111 developers only.
1112 Removed Options
1115 -T | --netsec
1116 Removed before version 6.3.0, the required underlying inet6_apps
1117 library had been discontinued and is no longer available.
1118
1121 All modes except ETRN require authentication of the client to the
1122 server. Normal user authentication in fetchmail is very much like the
1123 authentication mechanism of ftp(1). The correct user-id and password
1124 depend upon the underlying security system at the mailserver.
1125 If the mailserver is a Unix machine on which you have an ordinary user
1127 account, your regular login name and password are used with fetchmail.
1128 If you use the same login name on both the server and the client
1129 machines, you needn't worry about specifying a user-id with the -u
1130 option -- the default behavior is to use your login name on the client
1131 machine as the user-id on the server machine. If you use a different
1132 login name on the server machine, specify that login name with the -u
1133 option. e.g. if your login name is 'jsmith' on a machine named 'mail‐
1134 grunt', you would start fetchmail as follows:
1135 fetchmail -u jsmith mailgrunt
1137 The default behavior of fetchmail is to prompt you for your mailserver
1139 password before the connection is established. This is the safest way
1140 to use fetchmail and ensures that your password will not be compro‐
1141 mised. You may also specify your password in your ~/.fetchmailrc file.
1142 This is convenient when using fetchmail in daemon mode or with scripts.
1143 Using netrc files
1146 If you do not specify a password, and fetchmail cannot extract one from
1147 your ~/.fetchmailrc file, it will look for a ~/.netrc file in your home
1148 directory before requesting one interactively; if an entry matching the
1149 mailserver is found in that file, the password will be used. Fetchmail
1150 first looks for a match on poll name; if it finds none, it checks for a
1151 match on via name. See the ftp(1) man page for details of the syntax
1152 of the ~/.netrc file. To show a practical example, a .netrc might look
1153 like this:
1154 machine hermes.example.org
1156 login joe
1157 password topsecret
1158 You can repeat this block with different user information if you need
1160 to provide more than one password.
1161 This feature may allow you to avoid duplicating password information in
1163 more than one file.
1164 On mailservers that do not provide ordinary user accounts, your user-id
1166 and password are usually assigned by the server administrator when you
1167 apply for a mailbox on the server. Contact your server administrator
1168 if you don't know the correct user-id and password for your mailbox
1169 account.
1170
1172 Early versions of POP3 (RFC1081, RFC1225) supported a crude form of
1173 independent authentication using the .rhosts file on the mailserver
1174 side. Under this RPOP variant, a fixed per-user ID equivalent to a
1175 password was sent in clear over a link to a reserved port, with the
1176 command RPOP rather than PASS to alert the server that it should do
1177 special checking. RPOP is supported by fetchmail (you can specify
1178 'protocol RPOP' to have the program send 'RPOP' rather than 'PASS') but
1179 its use is strongly discouraged, and support will be removed from a
1180 future fetchmail version. This facility was vulnerable to spoofing and
1181 was withdrawn in RFC1460.
1182 RFC1460 introduced APOP authentication. In this variant of POP3, you
1184 register an APOP password on your server host (on some servers, the
1185 program to do this is called popauth(8)). You put the same password in
1186 your ~/.fetchmailrc file. Each time fetchmail logs in, it sends an MD5
1187 hash of your password and the server greeting time to the server, which
1188 can verify it by checking its authorization database.
1189 Note that APOP is no longer considered resistant against man-in-the-
1191 middle attacks.
1192 RETR or TOP
1194 fetchmail makes some efforts to make the server believe messages had
1195 not been retrieved, by using the TOP command with a large number of
1196 lines when possible. TOP is a command that retrieves the full header
1197 and a fetchmail-specified amount of body lines. It is optional and
1198 therefore not implemented by all servers, and some are known to imple‐
1199 ment it improperly. On many servers however, the RETR command which
1200 retrieves the full message with header and body, sets the "seen" flag
1201 (for instance, in a web interface), whereas the TOP command does not do
1202 that.
1203 fetchmail will always use the RETR command if "fetchall" is set.
1205 fetchmail will also use the RETR command if "keep" is set and "uidl" is
1206 unset. Finally, fetchmail will use the RETR command on Maillennium
1207 POP3/PROXY servers (used by Comcast) to avoid a deliberate TOP misin‐
1208 terpretation in this server that causes message corruption.
1209 In all other cases, fetchmail will use the TOP command. This implies
1211 that in "keep" setups, "uidl" must be set if "TOP" is desired.
1212 Note that this description is true for the current version of fetch‐
1214 mail, but the behavior may change in future versions. In particular,
1215 fetchmail may prefer the RETR command because the TOP command causes
1216 much grief on some servers and is only optional.
1217
1219 If your fetchmail was built with Kerberos support and you specify Ker‐
1220 beros authentication (either with --auth or the .fetchmailrc option
1221 authenticate kerberos_v4) it will try to get a Kerberos ticket from the
1222 mailserver at the start of each query. Note: if either the pollname or
1223 via name is 'hesiod', fetchmail will try to use Hesiod to look up the
1224 mailserver.
1225 If you use POP3 or IMAP with GSSAPI authentication, fetchmail will
1227 expect the server to have RFC1731- or RFC1734-conforming GSSAPI capa‐
1228 bility, and will use it. Currently this has only been tested over Ker‐
1229 beros V, so you're expected to already have a ticket-granting ticket.
1230 You may pass a username different from your principal name using the
1231 standard --user command or by the .fetchmailrc option user.
1232 If your IMAP daemon returns the PREAUTH response in its greeting line,
1234 fetchmail will notice this and skip the normal authentication step.
1235 This can be useful, e.g. if you start imapd explicitly using ssh. In
1236 this case you can declare the authentication value 'ssh' on that site
1237 entry to stop .fetchmail from asking you for a password when it starts
1238 up.
1239 If you use client authentication with TLS1 and your IMAP daemon returns
1241 the AUTH=EXTERNAL response, fetchmail will notice this and will use the
1242 authentication shortcut and will not send the passphrase. In this case
1243 you can declare the authentication value 'external'
1244 on that site to stop fetchmail from asking you for a password when it
1245 starts up.
1246 If you are using POP3, and the server issues a one-time-password chal‐
1248 lenge conforming to RFC1938, fetchmail will use your password as a pass
1249 phrase to generate the required response. This avoids sending secrets
1250 over the net unencrypted.
1251 Compuserve's RPA authentication is supported. If you compile in the
1253 support, fetchmail will try to perform an RPA pass-phrase authentica‐
1254 tion instead of sending over the password en clair if it detects "@com‐
1255 puserve.com" in the hostname.
1256 If you are using IMAP, Microsoft's NTLM authentication (used by Micro‐
1258 soft Exchange) is supported. If you compile in the support, fetchmail
1259 will try to perform an NTLM authentication (instead of sending over the
1260 password en clair) whenever the server returns AUTH=NTLM in its capa‐
1261 bility response. Specify a user option value that looks like
1262 'user@domain': the part to the left of the @ will be passed as the
1263 username and the part to the right as the NTLM domain.
1264 Secure Socket Layers (SSL) and Transport Layer Security (TLS)
1267 All retrieval protocols can use SSL or TLS wrapping for the transport.
1268 Additionally, POP3 and IMAP retrival can also negotiate SSL/TLS by
1269 means of STARTTLS (or STLS).
1270 Note that fetchmail currently uses the OpenSSL library, which is se‐
1272 verely underdocumented, so failures may occur just because the program‐
1273 mers are not aware of OpenSSL's requirement of the day. For instance,
1274 since v6.3.16, fetchmail calls OpenSSL_add_all_algorithms(), which is
1275 necessary to support certificates using SHA256 on OpenSSL 0.9.8 -- this
1276 information is deeply hidden in the documentation and not at all obvi‐
1277 ous. Please do not hesitate to report subtle SSL failures.
1278 You can access SSL encrypted services by specifying the options start‐
1280 ing with --ssl, such as --ssl, --sslproto, --sslcertck, and others.
1281 You can also do this using the corresponding user options in the
1282 .fetchmailrc file. Some services, such as POP3 and IMAP, have differ‐
1283 ent well known ports defined for the SSL encrypted services. The
1284 encrypted ports will be selected automatically when SSL is enabled and
1285 no explicit port is specified. Also, the --sslcertck command line or
1286 sslcertck run control file option should be used to force strict cer‐
1287 tificate checking with older fetchmail versions - see below.
1288 If SSL is not configured, fetchmail will usually opportunistically try
1290 to use STARTTLS. STARTTLS can be enforced by using --sslproto auto and
1291 defeated by using --sslproto ''. TLS connections use the same port as
1292 the unencrypted version of the protocol and negotiate TLS via special
1293 command. The --sslcertck command line or sslcertck run control file
1294 option should be used to force strict certificate checking - see below.
1295 --sslcertck is recommended: When connecting to an SSL or TLS encrypted
1297 server, the server presents a certificate to the client for validation.
1298 The certificate is checked to verify that the common name in the cer‐
1299 tificate matches the name of the server being contacted and that the
1300 effective and expiration dates in the certificate indicate that it is
1301 currently valid. If any of these checks fail, a warning message is
1302 printed, but the connection continues. The server certificate does not
1303 need to be signed by any specific Certifying Authority and may be a
1304 "self-signed" certificate. If the --sslcertck command line option or
1305 sslcertck run control file option is used, fetchmail will instead abort
1306 if any of these checks fail, because it must assume that there is a
1307 man-in-the-middle attack in this scenario, hence fetchmail must not
1308 expose cleartext passwords. Use of the sslcertck or --sslcertck option
1309 is therefore advised; it has become the default in fetchmail 6.4.0.
1310 Some SSL encrypted servers may request a client side certificate. A
1312 client side public SSL certificate and private SSL key may be speci‐
1313 fied. If requested by the server, the client certificate is sent to
1314 the server for validation. Some servers may require a valid client
1315 certificate and may refuse connections if a certificate is not provided
1316 or if the certificate is not valid. Some servers may require client
1317 side certificates be signed by a recognized Certifying Authority. The
1318 format for the key files and the certificate files is that required by
1319 the underlying SSL libraries (OpenSSL in the general case).
1320 A word of care about the use of SSL: While above mentioned setup with
1322 self-signed server certificates retrieved over the wires can protect
1323 you from a passive eavesdropper, it doesn't help against an active
1324 attacker. It's clearly an improvement over sending the passwords in
1325 clear, but you should be aware that a man-in-the-middle attack is triv‐
1326 ially possible (in particular with tools such as dsniff ⟨https://
1327 monkey.org/~dugsong/dsniff/⟩, ). Use of strict certificate checking
1328 with a certification authority recognized by server and client, or per‐
1329 haps of an SSH tunnel (see below for some examples) is preferable if
1330 you care seriously about the security of your mailbox and passwords.
1331 ESMTP AUTH
1334 fetchmail also supports authentication to the ESMTP server on the
1335 client side according to RFC 2554. You can specify a name/password
1336 pair to be used with the keywords 'esmtpname' and 'esmtppassword'; the
1337 former defaults to the username of the calling user.
1338
1341 Introducing the daemon mode
1342 In daemon mode, fetchmail puts itself into the background and runs for‐
1343 ever, querying each specified host and then sleeping for a given
1344 polling interval.
1345 Starting the daemon mode
1347 There are several ways to make fetchmail work in daemon mode. On the
1348 command line, --daemon <interval> or -d <interval> option runs fetch‐
1349 mail in daemon mode. You must specify a numeric argument which is a
1350 polling interval (time to wait after completing a whole poll cycle with
1351 the last server and before starting the next poll cycle with the first
1352 server) in seconds.
1353 Example: simply invoking
1355 fetchmail -d 900
1357 will, therefore, poll all the hosts described in your ~/.fetchmailrc
1359 file (except those explicitly excluded with the 'skip' verb) a bit less
1360 often than once every 15 minutes (exactly: 15 minutes + time that the
1361 poll takes).
1362 It is also possible to set a polling interval in your ~/.fetchmailrc
1364 file by saying 'set daemon <interval>', where <interval> is an integer
1365 number of seconds. If you do this, fetchmail will always start in dae‐
1366 mon mode unless you override it with the command-line option --daemon 0
1367 or -d0.
1368 Only one daemon process is permitted per user; in daemon mode, fetch‐
1370 mail sets up a per-user lockfile to guarantee this. (You can however
1371 cheat and set the FETCHMAILHOME environment variable to overcome this
1372 setting, but in that case, it is your responsibility to make sure you
1373 aren't polling the same server with two processes at the same time.)
1374 Awakening the background daemon
1376 Normally, calling fetchmail with a daemon in the background sends a
1377 wake-up signal to the daemon and quits without output. The background
1378 daemon then starts its next poll cycle immediately. The wake-up sig‐
1379 nal, SIGUSR1, can also be sent manually. The wake-up action also clears
1380 any 'wedged' flags indicating that connections have wedged due to
1381 failed authentication or multiple timeouts.
1382 Terminating the background daemon
1384 The option -q or --quit will kill a running daemon process instead of
1385 waking it up (if there is no such process, fetchmail will notify you).
1386 If the --quit option appears last on the command line, fetchmail will
1387 kill the running daemon process and then quit. Otherwise, fetchmail
1388 will first kill a running daemon process and then continue running with
1389 the other options.
1390 Useful options for daemon mode
1392 The -L <filename> or --logfile <filename> option (keyword: set logfile)
1393 is only effective when fetchmail is detached and in daemon mode. Note
1394 that the logfile must exist before fetchmail is run, you can use the
1395 touch(1) command with the filename as its sole argument to create it.
1396 This option allows you to redirect status messages into a specified
1397 logfile (follow the option with the logfile name). The logfile is
1398 opened for append, so previous messages aren't deleted. This is pri‐
1399 marily useful for debugging configurations. Note that fetchmail does
1400 not detect if the logfile is rotated, the logfile is only opened once
1401 when fetchmail starts. You need to restart fetchmail after rotating the
1402 logfile and before compressing it (if applicable).
1403 The --syslog option (keyword: set syslog) allows you to redirect status
1405 and error messages emitted to the syslog(3) system daemon if available.
1406 Messages are logged with an id of fetchmail, the facility LOG_MAIL, and
1407 priorities LOG_ERR, LOG_ALERT or LOG_INFO. This option is intended for
1408 logging status and error messages which indicate the status of the dae‐
1409 mon and the results while fetching mail from the server(s). Error mes‐
1410 sages for command line options and parsing the .fetchmailrc file are
1411 still written to stderr, or to the specified log file. The --nosyslog
1412 option turns off use of syslog(3), assuming it's turned on in the
1413 ~/.fetchmailrc file. This option is overridden, in certain situations,
1414 by --logfile (which see).
1415 The -N or --nodetach option suppresses backgrounding and detachment of
1417 the daemon process from its control terminal. This is useful for
1418 debugging or when fetchmail runs as the child of a supervisor process
1419 such as init(8) or Gerrit Pape's runit(8). Note that this also causes
1420 the logfile option to be ignored.
1421 Note that while running in daemon mode polling a POP2 or IMAP2bis
1423 server, transient errors (such as DNS failures or sendmail delivery
1424 refusals) may force the fetchall option on for the duration of the next
1425 polling cycle. This is a robustness feature. It means that if a mes‐
1426 sage is fetched (and thus marked seen by the mailserver) but not deliv‐
1427 ered locally due to some transient error, it will be re-fetched during
1428 the next poll cycle. (The IMAP logic doesn't delete messages until
1429 they're delivered, so this problem does not arise.)
1430 If you touch or change the ~/.fetchmailrc file while fetchmail is run‐
1432 ning in daemon mode, this will be detected at the beginning of the next
1433 poll cycle. When a changed ~/.fetchmailrc is detected, fetchmail
1434 rereads it and restarts from scratch (using exec(2); no state informa‐
1435 tion is retained in the new instance). Note that if fetchmail needs to
1436 query for passwords, of that if you break the ~/.fetchmailrc file's
1437 syntax, the new instance will softly and silently vanish away on
1438 startup.
1439
1442 The --postmaster <name> option (keyword: set postmaster) specifies the
1443 last-resort username to which multidrop mail is to be forwarded if no
1444 matching local recipient can be found. It is also used as destination
1445 of undeliverable mail if the 'bouncemail' global option is off and
1446 additionally for spam-blocked mail if the 'bouncemail' global option is
1447 off and the 'spambounce' global option is on. This option defaults to
1448 the user who invoked fetchmail. If the invoking user is root, then the
1449 default of this option is the user 'postmaster'. Setting postmaster to
1450 the empty string causes such mail as described above to be discarded -
1451 this however is usually a bad idea. See also the description of the
1452 'FETCHMAILUSER' environment variable in the ENVIRONMENT section below.
1453 The --nobounce behaves like the "set no bouncemail" global option,
1455 which see.
1456 The --invisible option (keyword: set invisible) tries to make fetchmail
1458 invisible. Normally, fetchmail behaves like any other MTA would -- it
1459 generates a Received header into each message describing its place in
1460 the chain of transmission, and tells the MTA it forwards to that the
1461 mail came from the machine fetchmail itself is running on. If the
1462 invisible option is on, the Received header is suppressed and fetchmail
1463 tries to spoof the MTA it forwards to into thinking it came directly
1464 from the mailserver host.
1465 The --showdots option (keyword: set showdots) forces fetchmail to show
1467 progress dots even if the output goes to a file or fetchmail is not in
1468 verbose mode. Fetchmail shows the dots by default when run in --ver‐
1469 bose mode and output goes to console. This option is ignored in
1470 --silent mode.
1471 By specifying the --tracepolls option, you can ask fetchmail to add
1473 information to the Received header on the form "polling {label} account
1474 {user}", where {label} is the account label (from the specified rcfile,
1475 normally ~/.fetchmailrc) and {user} is the username which is used to
1476 log on to the mail server. This header can be used to make filtering
1477 email where no useful header information is available and you want mail
1478 from different accounts sorted into different mailboxes (this could,
1479 for example, occur if you have an account on the same server running a
1480 mailing list, and are subscribed to the list using that account). The
1481 default is not adding any such header. In .fetchmailrc, this is called
1482 'tracepolls'.
1483
1486 The protocols fetchmail uses to talk to mailservers are next to bullet‐
1487 proof. In normal operation forwarding to port 25, no message is ever
1488 deleted (or even marked for deletion) on the host until the SMTP lis‐
1489 tener on the client side has acknowledged to fetchmail that the message
1490 has been either accepted for delivery or rejected due to a spam block.
1491 When forwarding to an MDA, however, there is more possibility of error.
1493 Some MDAs are 'safe' and reliably return a nonzero status on any deliv‐
1494 ery error, even one due to temporary resource limits. The maildrop(1)
1495 program is like this; so are most programs designed as mail transport
1496 agents, such as sendmail(1), including the sendmail wrapper of Postfix
1497 and exim(1). These programs give back a reliable positive acknowledge‐
1498 ment and can be used with the mda option with no risk of mail loss.
1499 Unsafe MDAs, though, may return 0 even on delivery failure. If this
1500 happens, you will lose mail.
1501 The normal mode of fetchmail is to try to download only 'new' messages,
1503 leaving untouched (and undeleted) messages you have already read
1504 directly on the server (or fetched with a previous fetchmail --keep).
1505 But you may find that messages you've already read on the server are
1506 being fetched (and deleted) even when you don't specify --all. There
1507 are several reasons this can happen.
1508 One could be that you're using POP2. The POP2 protocol includes no
1510 representation of 'new' or 'old' state in messages, so fetchmail must
1511 treat all messages as new all the time. But POP2 is obsolete, so this
1512 is unlikely.
1513 A potential POP3 problem might be servers that insert messages in the
1515 middle of mailboxes (some VMS implementations of mail are rumored to do
1516 this). The fetchmail code assumes that new messages are appended to
1517 the end of the mailbox; when this is not true it may treat some old
1518 messages as new and vice versa. Using UIDL whilst setting fastuidl 0
1519 might fix this, otherwise, consider switching to IMAP.
1520 Yet another POP3 problem is that if they can't make tempfiles in the
1522 user's home directory, some POP3 servers will hand back an undocumented
1523 response that causes fetchmail to spuriously report "No mail".
1524 The IMAP code uses the presence or absence of the server flag \Seen to
1526 decide whether or not a message is new. This isn't the right thing to
1527 do, fetchmail should check the UIDVALIDITY and use UID, but it doesn't
1528 do that yet. Under Unix, it counts on your IMAP server to notice the
1529 BSD-style Status flags set by mail user agents and set the \Seen flag
1530 from them when appropriate. All Unix IMAP servers we know of do this,
1531 though it's not specified by the IMAP RFCs. If you ever trip over a
1532 server that doesn't, the symptom will be that messages you have already
1533 read on your host will look new to the server. In this (unlikely)
1534 case, only messages you fetched with fetchmail --keep will be both
1535 undeleted and marked old.
1536 In ETRN and ODMR modes, fetchmail does not actually retrieve messages;
1538 instead, it asks the server's SMTP listener to start a queue flush to
1539 the client via SMTP. Therefore it sends only undelivered messages.
1540
1543 Many SMTP listeners allow administrators to set up 'spam filters' that
1544 block unsolicited email from specified domains. A MAIL FROM or DATA
1545 line that triggers this feature will elicit an SMTP response which
1546 (unfortunately) varies according to the listener.
1547 Newer versions of sendmail return an error code of 571.
1549 According to RFC2821, the correct thing to return in this situation is
1551 550 "Requested action not taken: mailbox unavailable" (the draft adds
1552 "[E.g., mailbox not found, no access, or command rejected for policy
1553 reasons].").
1554 Older versions of the exim MTA return 501 "Syntax error in parameters
1556 or arguments".
1557 The postfix MTA runs 554 as an antispam response.
1559 Zmailer may reject code with a 500 response (followed by an enhanced
1561 status code that contains more information).
1562 Return codes which fetchmail treats as antispam responses and discards
1564 the message can be set with the 'antispam' option. This is one of the
1565 only three circumstance under which fetchmail ever discards mail (the
1566 others are the 552 and 553 errors described below, and the suppression
1567 of multidropped messages with a message-ID already seen).
1568 If fetchmail is fetching from an IMAP server, the antispam response
1570 will be detected and the message rejected immediately after the headers
1571 have been fetched, without reading the message body. Thus, you won't
1572 pay for downloading spam message bodies.
1573 By default, the list of antispam responses is empty.
1575 If the spambounce global option is on, mail that is spam-blocked trig‐
1577 gers an RFC1892/RFC1894 bounce message informing the originator that we
1578 do not accept mail from it. See also BUGS.
1579
1582 Besides the spam-blocking described above, fetchmail takes special
1583 actions — that may be modified by the --softbounce option — on the fol‐
1584 lowing SMTP/ESMTP error response codes
1585 452 (insufficient system storage)
1587 Leave the message in the server mailbox for later retrieval.
1588 552 (message exceeds fixed maximum message size)
1590 Delete the message from the server. Send bounce-mail to the orig‐
1591 inator.
1592 553 (invalid sending domain)
1594 Delete the message from the server. Don't even try to send
1595 bounce-mail to the originator.
1596 Other errors greater or equal to 500 trigger bounce mail back to the
1598 originator, unless suppressed by --softbounce. See also BUGS.
1599
1602 The preferred way to set up fetchmail is to write a .fetchmailrc file
1603 in your home directory (you may do this directly, with a text editor,
1604 or indirectly via fetchmailconf). When there is a conflict between the
1605 command-line arguments and the arguments in this file, the command-line
1606 arguments take precedence.
1607 To protect the security of your passwords, your ~/.fetchmailrc may not
1609 normally have more than 0700 (u=rwx,g=,o=) permissions; fetchmail will
1610 complain and exit otherwise (this check is suppressed when --version is
1611 on).
1612 You may read the .fetchmailrc file as a list of commands to be executed
1614 when fetchmail is called with no arguments.
1615 Run Control Syntax
1617 Comments begin with a '#' and extend through the end of the line. Oth‐
1618 erwise the file consists of a series of server entries or global option
1619 statements in a free-format, token-oriented syntax.
1620 There are four kinds of tokens: grammar keywords, numbers (i.e. decimal
1622 digit sequences), unquoted strings, and quoted strings. A quoted
1623 string is bounded by double quotes and may contain whitespace (and
1624 quoted digits are treated as a string). Note that quoted strings will
1625 also contain line feed characters if they run across two or more lines,
1626 unless you use a backslash to join lines (see below). An unquoted
1627 string is any whitespace-delimited token that is neither numeric,
1628 string quoted nor contains the special characters ',', ';', ':', or
1629 '='.
1630 Any amount of whitespace separates tokens in server entries, but is
1632 otherwise ignored. You may use backslash escape sequences (\n for LF,
1633 \t for HT, \b for BS, \r for CR, \nnn for decimal (where nnn cannot
1634 start with a 0), \0ooo for octal, and \xhh for hex) to embed non-print‐
1635 able characters or string delimiters in strings. In quoted strings, a
1636 backslash at the very end of a line will cause the backslash itself and
1637 the line feed (LF or NL, new line) character to be ignored, so that you
1638 can wrap long strings. Without the backslash at the line end, the line
1639 feed character would become part of the string.
1640 Warning: while these resemble C-style escape sequences, they are not
1642 the same. fetchmail only supports these eight styles. C supports more
1643 escape sequences that consist of backslash (\) and a single character,
1644 but does not support decimal codes and does not require the leading 0
1645 in octal notation. Example: fetchmail interprets \233 the same as \xE9
1646 (Latin small letter e with acute), where C would interpret \233 as
1647 octal 0233 = \x9B (CSI, control sequence introducer).
1648 Each server entry consists of one of the keywords 'poll' or 'skip',
1650 followed by a server name, followed by server options, followed by any
1651 number of user (or username) descriptions, followed by user options.
1652 Note: the most common cause of syntax errors is mixing up user and
1653 server options or putting user options before the user descriptions.
1654 For backward compatibility, the word 'server' is a synonym for 'poll'.
1656 You can use the noise keywords 'and', 'with', 'has', 'wants', and
1658 'options' anywhere in an entry to make it resemble English. They're
1659 ignored, but but can make entries much easier to read at a glance. The
1660 punctuation characters ':', ';' and ',' are also ignored.
1661 Poll vs. Skip
1663 The 'poll' verb tells fetchmail to query this host when it is run with
1664 no arguments. The 'skip' verb tells fetchmail not to poll this host
1665 unless it is explicitly named on the command line. (The 'skip' verb
1666 allows you to experiment with test entries safely, or easily disable
1667 entries for hosts that are temporarily down.)
1668 Keyword/Option Summary
1670 Here are the legal options. Keyword suffixes enclosed in square brack‐
1671 ets are optional. Those corresponding to short command-line options
1672 are followed by '-' and the appropriate option letter. If option is
1673 only relevant to a single mode of operation, it is noted as 's' or 'm'
1674 for singledrop- or multidrop-mode, respectively.
1675 Here are the legal global options:
1677 Keyword Opt Mode Function
1680 ────────────────────────────────────────────────────────────────────
1681 set daemon -d Set a background poll interval in
1682 seconds.
1683 set postmaster Give the name of the last-resort
1684 mail recipient (default: user run‐
1685 ning fetchmail, "postmaster" if
1686 run by the root user)
1687 set bouncemail Direct error mail to the sender
1688 (default)
1689 set no bouncemail Direct error mail to the local
1690 postmaster (as per the 'postmas‐
1691 ter' global option above).
1692 set no spambounce Do not bounce spam-blocked mail
1693 (default).
1694 set spambounce Bounce blocked spam-blocked mail
1695 (as per the 'antispam' user
1696 option) back to the destination as
1697 indicated by the 'bouncemail'
1698 global option. Warning: Do not
1699 use this to bounce spam back to
1700 the sender - most spam is sent
1701 with false sender address and thus
1702 this option hurts innocent
1703 bystanders.
1704 set no softbounce Delete permanently undeliverable
1705 mail. It is recommended to use
1706 this option if the configuration
1707 has been thoroughly tested.
1708 set softbounce Keep permanently undeliverable
1709 mail as though a temporary error
1710 had occurred (default).
1711 set logfile -L Name of a file to append error and
1714 status messages to. Only effec‐
1715 tive in daemon mode and if fetch‐
1716 mail detaches. If effective,
1717 overrides set syslog.
1718 set pidfile -p Name of the PID file.
1719 set idfile -i Name of the file to store UID
1720 lists in.
1721 set syslog Do error logging through sys‐
1722 log(3). May be overridden by set
1723 logfile.
1724 set no syslog Turn off error logging through
1725 syslog(3). (default)
1726 set properties String value that is ignored by
1727 fetchmail (may be used by exten‐
1728 sion scripts).
1729 Here are the legal server options:
1731 Keyword Opt Mode Function
1734 ─────────────────────────────────────────────────────────────────
1735 via Specify DNS name of mailserver,
1736 overriding poll name
1737 proto[col] -p Specify protocol (case insensi‐
1738 tive): POP2, POP3, IMAP, APOP,
1739 KPOP
1740 local[domains] m Specify domain(s) to be regarded
1741 as local
1742 port Specify TCP/IP service port (obso‐
1743 lete, use 'service' instead).
1744 service -P Specify service name (a numeric
1745 value is also allowed and consid‐
1746 ered a TCP/IP port number).
1747 auth[enticate] Set authentication type (default
1748 'any')
1749 timeout -t Server inactivity timeout in sec‐
1750 onds (default 300)
1751 envelope -E m Specify envelope-address header
1752 name
1753 no envelope m Disable looking for envelope
1754 address
1755 qvirtual -Q m Qmail virtual domain prefix to
1756 remove from user name
1757 aka m Specify alternate DNS names of
1758 mailserver
1759 interface -I specify IP interface(s) that must
1760 be up for server poll to take
1761 place
1762 monitor -M Specify IP address to monitor for
1763 activity
1764 plugin Specify command through which to
1765 make server connections.
1766 plugout Specify command through which to
1767 make listener connections.
1768 dns m Enable DNS lookup for multidrop
1769 (default)
1770 no dns m Disable DNS lookup for multidrop
1771 checkalias m Do comparison by IP address for
1772 multidrop
1773 no checkalias m Do comparison by name for mul‐
1774 tidrop (default)
1775 uidl -U Force POP3 to use client-side
1776 UIDLs (recommended)
1777 no uidl Turn off POP3 use of client-side
1778 UIDLs (default)
1779 interval Only check this site every N poll
1780 cycles; N is a numeric argument.
1781 tracepolls Add poll tracing information to
1782 the Received header
1783 principal Set Kerberos principal (only use‐
1784 ful with IMAP and kerberos)
1785 esmtpname Set name for RFC2554 authentica‐
1786 tion to the ESMTP server.
1787 esmtppassword Set password for RFC2554 authenti‐
1788 cation to the ESMTP server.
1789 bad-header How to treat messages with a bad
1791 header. Can be reject (default) or
1792 accept.
1793 Here are the legal user descriptions and options:
1795 Keyword Opt Mode Function
1798 ───────────────────────────────────────────────────────────────────────
1799 user[name] -u This is the user description and
1800 must come first after server
1801 description and after possible
1802 server options, and before user
1803 options.
1804 It sets the remote user name if by
1806 itself or followed by 'there', or
1807 the local user name if followed by
1808 'here'.
1809 is Connect local and remote user
1810 names
1811 to Connect local and remote user
1812 names
1813 pass[word] Specify remote account password
1814 ssl Connect to server over the speci‐
1815 fied base protocol using SSL
1816 encryption
1817 sslcert Specify file for client side pub‐
1818 lic SSL certificate
1819 sslcertck Enable strict certificate checking
1820 and abort connection on failure.
1821 Default only since fetchmail
1822 v6.4.0.
1823 no sslcertck Disable strict certificate check‐
1824 ing and permit connections to con‐
1825 tinue on failed verification. Dis‐
1826 couraged. Should only be used
1827 together with sslfingerprint.
1828 sslcertfile Specify file with trusted CA cer‐
1829 tificates
1830 sslcertpath Specify c_rehash-ed directory with
1831 trusted CA certificates.
1832 sslfingerprint <HASH> Specify the expected server cer‐
1833 tificate finger print from an MD5
1834 hash. Fetchmail will disconnect
1835 and log an error if it does not
1836 match.
1837 sslkey Specify file for client side pri‐
1838 vate SSL key
1839 sslproto Force ssl protocol for connection
1840 folder -r Specify remote folder to query
1841 smtphost -S Specify smtp host(s) to forward to
1842 fetchdomains m Specify domains for which mail
1843 should be fetched
1844 smtpaddress -D Specify the domain to be put in
1845 RCPT TO lines
1846 smtpname Specify the user and domain to be
1847 put in RCPT TO lines
1848 antispam -Z Specify what SMTP returns are
1849 interpreted as spam-policy blocks
1850 mda -m Specify MDA for local delivery
1851 bsmtp Specify BSMTP batch file to append
1852 to
1853 preconnect Command to be executed before each
1854 connection
1855 postconnect Command to be executed after each
1856 connection
1857 keep -k Don't delete seen messages from
1858 server (for POP3, uidl is recom‐
1859 mended)
1860 flush -F Flush all seen messages before
1861 querying (DANGEROUS)
1862 limitflush Flush all oversized messages
1863 before querying
1864 fetchall -a Fetch all messages whether seen or
1865 not
1866 rewrite Rewrite destination addresses for
1868 reply (default)
1869 stripcr Strip carriage returns from ends
1870 of lines
1871 forcecr Force carriage returns at ends of
1872 lines
1873 pass8bits Force BODY=8BITMIME to ESMTP lis‐
1874 tener
1875 dropstatus Strip Status and X-Mozilla-Status
1876 lines out of incoming mail
1877 dropdelivered Strip Delivered-To lines out of
1878 incoming mail
1879 mimedecode Convert quoted-printable to 8-bit
1880 in MIME messages
1881 idle Idle waiting for new messages
1882 after each poll (IMAP only)
1883 no keep -K Delete seen messages from server
1884 (default)
1885 no flush Don't flush all seen messages
1886 before querying (default)
1887 no fetchall Retrieve only new messages
1888 (default)
1889 no rewrite Don't rewrite headers
1890 no stripcr Don't strip carriage returns
1891 (default)
1892 no forcecr Don't force carriage returns at
1893 EOL (default)
1894 no pass8bits Don't force BODY=8BITMIME to ESMTP
1895 listener (default)
1896 no dropstatus Don't drop Status headers
1897 (default)
1898 no dropdelivered Don't drop Delivered-To headers
1899 (default)
1900 no mimedecode Don't convert quoted-printable to
1901 8-bit in MIME messages (default)
1902 no idle Don't idle waiting for new mes‐
1903 sages after each poll (IMAP only)
1904 limit -l Set message size limit
1905 warnings -w Set message size warning interval
1906 batchlimit -b Max # messages to forward in sin‐
1907 gle connect
1908 fetchlimit -B Max # messages to fetch in single
1909 connect
1910 fetchsizelimit Max # message sizes to fetch in
1911 single transaction
1912 fastuidl Use binary search for first unseen
1913 message (POP3 only)
1914 expunge -e Perform an expunge on every #th
1915 message (IMAP and POP3 only)
1916 properties String value is ignored by fetch‐
1917 mail (may be used by extension
1918 scripts)
1919 All user options must begin with a user description (user or username
1921 option) and follow all server descriptions and options.
1922 In the .fetchmailrc file, the 'envelope' string argument may be pre‐
1924 ceded by a whitespace-separated number. This number, if specified, is
1925 the number of such headers to skip over (that is, an argument of 1
1926 selects the second header of the given type). This is sometime useful
1927 for ignoring bogus envelope headers created by an ISP's local delivery
1928 agent or internal forwards (through mail inspection systems, for
1929 instance).
1930 Keywords Not Corresponding To Option Switches
1932 The 'folder' and 'smtphost' options (unlike their command-line equiva‐
1933 lents) can take a space- or comma-separated list of names following
1934 them.
1935 All options correspond to the obvious command-line arguments, except
1937 the following: 'via', 'interval', 'aka', 'is', 'to', 'dns'/'no dns',
1938 'checkalias'/'no checkalias', 'password', 'preconnect', 'postconnect',
1939 'localdomains', 'stripcr'/'no stripcr', 'forcecr'/'no forcecr',
1940 'pass8bits'/'no pass8bits' 'dropstatus/no dropstatus', 'dropdeliv‐
1941 ered/no dropdelivered', 'mimedecode/no mimedecode', 'no idle', and 'no
1942 envelope'.
1943 The 'via' option is for if you want to have more than one configuration
1945 pointing at the same site. If it is present, the string argument will
1946 be taken as the actual DNS name of the mailserver host to query. This
1947 will override the argument of poll, which can then simply be a distinct
1948 label for the configuration (e.g. what you would give on the command
1949 line to explicitly query this host).
1950 The 'interval' option (which takes a numeric argument) allows you to
1952 poll a server less frequently than the basic poll interval. If you say
1953 'interval N' the server this option is attached to will only be queried
1954 every N poll intervals.
1955 Singledrop vs. Multidrop options
1957 Please ensure you read the section titled THE USE AND ABUSE OF MUL‐
1958 TIDROP MAILBOXES if you intend to use multidrop mode.
1959 The 'is' or 'to' keywords associate the following local (client)
1961 name(s) (or server-name to client-name mappings separated by =) with
1962 the mailserver user name in the entry. If an is/to list has '*' as its
1963 last name, unrecognized names are simply passed through. Note that
1964 until fetchmail version 6.3.4 inclusively, these lists could only con‐
1965 tain local parts of user names (fetchmail would only look at the part
1966 before the @ sign). fetchmail versions 6.3.5 and newer support full
1967 addresses on the left hand side of these mappings, and they take prece‐
1968 dence over any 'localdomains', 'aka', 'via' or similar mappings.
1969 A single local name can be used to support redirecting your mail when
1971 your username on the client machine is different from your name on the
1972 mailserver. When there is only a single local name, mail is forwarded
1973 to that local username regardless of the message's Received, To, Cc,
1974 and Bcc headers. In this case, fetchmail never does DNS lookups.
1975 When there is more than one local name (or name mapping), fetchmail
1977 looks at the envelope header, if configured, and otherwise at the
1978 Received, To, Cc, and Bcc headers of retrieved mail (this is 'multidrop
1979 mode'). It looks for addresses with hostname parts that match your
1980 poll name or your 'via', 'aka' or 'localdomains' options, and usually
1981 also for hostname parts which DNS tells it are aliases of the
1982 mailserver. See the discussion of 'dns', 'checkalias', 'localdomains',
1983 and 'aka' for details on how matching addresses are handled.
1984 If fetchmail cannot match any mailserver usernames or localdomain
1986 addresses, the mail will be bounced. Normally it will be bounced to
1987 the sender, but if the 'bouncemail' global option is off, the mail will
1988 go to the local postmaster instead. (see the 'postmaster' global
1989 option). See also BUGS.
1990 The 'dns' option (normally on) controls the way addresses from mul‐
1992 tidrop mailboxes are checked. On, it enables logic to check each host
1993 address that does not match an 'aka' or 'localdomains' declaration by
1994 looking it up with DNS. When a mailserver username is recognized
1995 attached to a matching hostname part, its local mapping is added to the
1996 list of local recipients.
1997 The 'checkalias' option (normally off) extends the lookups performed by
1999 the 'dns' keyword in multidrop mode, providing a way to cope with
2000 remote MTAs that identify themselves using their canonical name, while
2001 they're polled using an alias. When such a server is polled, checks to
2002 extract the envelope address fail, and fetchmail reverts to delivery
2003 using the To/Cc/Bcc headers (See below 'Header vs. Envelope
2004 addresses'). Specifying this option instructs fetchmail to retrieve
2005 all the IP addresses associated with both the poll name and the name
2006 used by the remote MTA and to do a comparison of the IP addresses.
2007 This comes in handy in situations where the remote server undergoes
2008 frequent canonical name changes, that would otherwise require modifica‐
2009 tions to the rcfile. 'checkalias' has no effect if 'no dns' is speci‐
2010 fied in the rcfile.
2011 The 'aka' option is for use with multidrop mailboxes. It allows you to
2013 pre-declare a list of DNS aliases for a server. This is an optimiza‐
2014 tion hack that allows you to trade space for speed. When fetchmail,
2015 while processing a multidrop mailbox, grovels through message headers
2016 looking for names of the mailserver, pre-declaring common ones can save
2017 it from having to do DNS lookups. Note: the names you give as argu‐
2018 ments to 'aka' are matched as suffixes -- if you specify (say) 'aka
2019 netaxs.com', this will match not just a hostname netaxs.com, but any
2020 hostname that ends with '.netaxs.com'; such as (say) pop3.netaxs.com
2021 and mail.netaxs.com.
2022 The 'localdomains' option allows you to declare a list of domains which
2024 fetchmail should consider local. When fetchmail is parsing address
2025 lines in multidrop modes, and a trailing segment of a host name matches
2026 a declared local domain, that address is passed through to the listener
2027 or MDA unaltered (local-name mappings are not applied).
2028 If you are using 'localdomains', you may also need to specify 'no enve‐
2030 lope', which disables fetchmail's normal attempt to deduce an envelope
2031 address from the Received line or X-Envelope-To header or whatever
2032 header has been previously set by 'envelope'. If you set 'no envelope'
2033 in the defaults entry it is possible to undo that in individual entries
2034 by using 'envelope <string>'. As a special case, 'envelope "Received"'
2035 restores the default parsing of Received lines.
2036 The password option requires a string argument, which is the password
2038 to be used with the entry's server.
2039 The 'preconnect' keyword allows you to specify a shell command to be
2041 executed just before each time fetchmail establishes a mailserver con‐
2042 nection. This may be useful if you are attempting to set up secure POP
2043 connections with the aid of ssh(1). If the command returns a nonzero
2044 status, the poll of that mailserver will be aborted.
2045 Similarly, the 'postconnect' keyword similarly allows you to specify a
2047 shell command to be executed just after each time a mailserver connec‐
2048 tion is taken down.
2049 The 'forcecr' option controls whether lines terminated by LF only are
2051 given CRLF termination before forwarding. Strictly speaking RFC821
2052 requires this, but few MTAs enforce the requirement so this option is
2053 normally off (only one such MTA, qmail, is in significant use at time
2054 of writing).
2055 The 'stripcr' option controls whether carriage returns are stripped out
2057 of retrieved mail before it is forwarded. It is normally not necessary
2058 to set this, because it defaults to 'on' (CR stripping enabled) when
2059 there is an MDA declared but 'off' (CR stripping disabled) when for‐
2060 warding is via SMTP. If 'stripcr' and 'forcecr' are both on, 'stripcr'
2061 will override.
2062 The 'pass8bits' option exists to cope with Microsoft mail programs that
2064 stupidly slap a "Content-Transfer-Encoding: 7bit" on everything. With
2065 this option off (the default) and such a header present, fetchmail
2066 declares BODY=7BIT to an ESMTP-capable listener; this causes problems
2067 for messages actually using 8-bit ISO or KOI-8 character sets, which
2068 will be garbled by having the high bits of all characters stripped. If
2069 'pass8bits' is on, fetchmail is forced to declare BODY=8BITMIME to any
2070 ESMTP-capable listener. If the listener is 8-bit-clean (as all the
2071 major ones now are) the right thing will probably result.
2072 The 'dropstatus' option controls whether nonempty Status and X-Mozilla-
2074 Status lines are retained in fetched mail (the default) or discarded.
2075 Retaining them allows your MUA to see what messages (if any) were
2076 marked seen on the server. On the other hand, it can confuse some new-
2077 mail notifiers, which assume that anything with a Status line in it has
2078 been seen. (Note: the empty Status lines inserted by some buggy POP
2079 servers are unconditionally discarded.)
2080 The 'dropdelivered' option controls whether Delivered-To headers will
2082 be kept in fetched mail (the default) or discarded. These headers are
2083 added by Qmail and Postfix mailservers in order to avoid mail loops but
2084 may get in your way if you try to "mirror" a mailserver within the same
2085 domain. Use with caution.
2086 The 'mimedecode' option controls whether MIME messages using the
2088 quoted-printable encoding are automatically converted into pure 8-bit
2089 data. If you are delivering mail to an ESMTP-capable, 8-bit-clean lis‐
2090 tener (that includes all of the major MTAs like sendmail), then this
2091 will automatically convert quoted-printable message headers and data
2092 into 8-bit data, making it easier to understand when reading mail. If
2093 your e-mail programs know how to deal with MIME messages, then this
2094 option is not needed. The mimedecode option is off by default, because
2095 doing RFC2047 conversion on headers throws away character-set informa‐
2096 tion and can lead to bad results if the encoding of the headers differs
2097 from the body encoding.
2098 The 'idle' option is intended to be used with IMAP servers supporting
2100 the RFC2177 IDLE command extension, but does not strictly require it.
2101 If it is enabled, and fetchmail detects that IDLE is supported, an IDLE
2102 will be issued at the end of each poll. This will tell the IMAP server
2103 to hold the connection open and notify the client when new mail is
2104 available. If IDLE is not supported, fetchmail will simulate it by
2105 periodically issuing NOOP. If you need to poll a link frequently, IDLE
2106 can save bandwidth by eliminating TCP/IP connects and LOGIN/LOGOUT
2107 sequences. On the other hand, an IDLE connection will eat almost all of
2108 your fetchmail's time, because it will never drop the connection and
2109 allow other polls to occur unless the server times out the IDLE. It
2110 also doesn't work with multiple folders; only the first folder will
2111 ever be polled.
2112 The 'properties' option is an extension mechanism. It takes a string
2114 argument, which is ignored by fetchmail itself. The string argument
2115 may be used to store configuration information for scripts which
2116 require it. In particular, the output of '--configdump' option will
2117 make properties associated with a user entry readily available to a
2118 Python script.
2119 Miscellaneous Run Control Options
2121 The words 'here' and 'there' have useful English-like significance.
2122 Normally 'user eric is esr' would mean that mail for the remote user
2123 'eric' is to be delivered to 'esr', but you can make this clearer by
2124 saying 'user eric there is esr here', or reverse it by saying 'user esr
2125 here is eric there'
2126 Legal protocol identifiers for use with the 'protocol' keyword are:
2128 auto (or AUTO) (legacy, to be removed from future release)
2130 pop2 (or POP2) (legacy, to be removed from future release)
2131 pop3 (or POP3)
2132 sdps (or SDPS)
2133 imap (or IMAP)
2134 apop (or APOP)
2135 kpop (or KPOP)
2136 Legal authentication types are 'any', 'password', 'kerberos', 'ker‐
2139 beros_v4', 'kerberos_v5' and 'gssapi', 'cram-md5', 'otp', 'msn' (only
2140 for POP3), 'ntlm', 'ssh', 'external' (only IMAP). The 'password' type
2141 specifies authentication by normal transmission of a password (the
2142 password may be plain text or subject to protocol-specific encryption
2143 as in CRAM-MD5); 'kerberos' tells fetchmail to try to get a Kerberos
2144 ticket at the start of each query instead, and send an arbitrary string
2145 as the password; and 'gssapi' tells fetchmail to use GSSAPI authentica‐
2146 tion. See the description of the 'auth' keyword for more.
2147 Specifying 'kpop' sets POP3 protocol over port 1109 with Kerberos V4
2149 authentication. These defaults may be overridden by later options.
2150 There are some global option statements: 'set logfile' followed by a
2152 string sets the same global specified by --logfile. A command-line
2153 --logfile option will override this. Note that --logfile is only effec‐
2154 tive if fetchmail detaches itself from the terminal and the logfile
2155 already exists before fetchmail is run, and it overrides --syslog in
2156 this case. Also, 'set daemon' sets the poll interval as --daemon does.
2157 This can be overridden by a command-line --daemon option; in particular
2158 --daemon 0 can be used to force foreground operation. The 'set postmas‐
2159 ter' statement sets the address to which multidrop mail defaults if
2160 there are no local matches. Finally, 'set syslog' sends log messages
2161 to syslogd(8).
2162
2165 Fetchmail crashing
2166 There are various ways in that fetchmail may "crash", i. e. stop opera‐
2167 tion suddenly and unexpectedly. A "crash" usually refers to an error
2168 condition that the software did not handle by itself. A well-known
2169 failure mode is the "segmentation fault" or "signal 11" or "SIGSEGV" or
2170 just "segfault" for short. These can be caused by hardware or by soft‐
2171 ware problems. Software-induced segfaults can usually be reproduced
2172 easily and in the same place, whereas hardware-induced segfaults can go
2173 away if the computer is rebooted, or powered off for a few hours, and
2174 can happen in random locations even if you use the software the same
2175 way.
2176 For solving hardware-induced segfaults, find the faulty component and
2178 repair or replace it. The Sig11 FAQ ⟨https://www.bitwizard.nl/sig11/⟩
2179 may help you with details.
2180 For solving software-induced segfaults, the developers may need a
2182 "stack backtrace".
2183 Enabling fetchmail core dumps
2186 By default, fetchmail suppresses core dumps as these might contain
2187 passwords and other sensitive information. For debugging fetchmail
2188 crashes, obtaining a "stack backtrace" from a core dump is often the
2189 quickest way to solve the problem, and when posting your problem on a
2190 mailing list, the developers may ask you for a "backtrace".
2191 1. To get useful backtraces, fetchmail needs to be installed without
2193 getting stripped of its compilation symbols. Unfortunately, most
2194 binary packages that are installed are stripped, and core files from
2195 symbol-stripped programs are worthless. So you may need to recompile
2196 fetchmail. On many systems, you can type
2197 file `which fetchmail`
2199 to find out if fetchmail was symbol-stripped or not. If yours was
2201 unstripped, fine, proceed, if it was stripped, you need to recompile
2202 the source code first. You do not usually need to install fetchmail in
2203 order to debug it.
2204 2. The shell environment that starts fetchmail needs to enable core
2206 dumps. The key is the "maximum core (file) size" that can usually be
2207 configured with a tool named "limit" or "ulimit". See the documentation
2208 for your shell for details. In the popular bash shell, "ulimit -Sc
2209 unlimited" will allow the core dump.
2210 3. You need to tell fetchmail, too, to allow core dumps. To do this,
2212 run fetchmail with the -d0 -v options. It is often easier to also add
2213 --nosyslog -N as well.
2214 Finally, you need to reproduce the crash. You can just start fetchmail
2216 from the directory where you compiled it by typing ./fetchmail, so the
2217 complete command line will start with ./fetchmail -Nvd0 --nosyslog and
2218 perhaps list your other options.
2219 After the crash, run your debugger to obtain the core dump. The debug‐
2221 ger will often be GNU GDB, you can then type (adjust paths as neces‐
2222 sary) gdb ./fetchmail fetchmail.core and then, after GDB has started up
2223 and read all its files, type backtrace full, save the output (copy &
2224 paste will do, the backtrace will be read by a human) and then type
2225 quit to leave gdb. Note: on some systems, the core files have differ‐
2226 ent names, they might contain a number instead of the program name, or
2227 number and name, but it will usually have "core" as part of their name.
2228
2231 When trying to determine the originating address of a message, fetch‐
2232 mail looks through headers in the following order:
2233 Return-Path:
2235 Resent-Sender: (ignored if it doesn't contain an @ or !)
2236 Sender: (ignored if it doesn't contain an @ or !)
2237 Resent-From:
2238 From:
2239 Reply-To:
2240 Apparently-From:
2241 The originating address is used for logging, and to set the MAIL FROM
2243 address when forwarding to SMTP. This order is intended to cope grace‐
2244 fully with receiving mailing list messages in multidrop mode. The
2245 intent is that if a local address doesn't exist, the bounce message
2246 won't be returned blindly to the author or to the list itself, but
2247 rather to the list manager (which is less annoying).
2248 In multidrop mode, destination headers are processed as follows: First,
2250 fetchmail looks for the header specified by the 'envelope' option in
2251 order to determine the local recipient address. If the mail is
2252 addressed to more than one recipient, the Received line won't contain
2253 any information regarding recipient addresses.
2254 Then fetchmail looks for the Resent-To:, Resent-Cc:, and Resent-Bcc:
2256 lines. If they exist, they should contain the final recipients and
2257 have precedence over their To:/Cc:/Bcc: counterparts. If the Resent-*
2258 lines don't exist, the To:, Cc:, Bcc: and Apparently-To: lines are
2259 looked for. (The presence of a Resent-To: is taken to imply that the
2260 person referred by the To: address has already received the original
2261 copy of the mail.)
2262
2265 Note that although there are password declarations in a good many of
2266 the examples below, this is mainly for illustrative purposes. We rec‐
2267 ommend stashing account/password pairs in your $HOME/.netrc file, where
2268 they can be used not just by fetchmail but by ftp(1) and other pro‐
2269 grams.
2270 The basic format is:
2272 poll SERVERNAME protocol PROTOCOL username NAME password PASS‐
2275 WORD
2276 Example:
2279 poll pop.provider.net protocol pop3 username "jsmith" password "secret1"
2282 Or, using some abbreviations:
2285 poll pop.provider.net proto pop3 user "jsmith" password "secret1"
2288 Multiple servers may be listed:
2291 poll pop.provider.net proto pop3 user "jsmith" pass "secret1"
2294 poll other.provider.net proto pop2 user "John.Smith" pass "My^Hat"
2295 Here's the same version with more whitespace and some noise words:
2298 poll pop.provider.net proto pop3
2301 user "jsmith", with password secret1, is "jsmith" here;
2302 poll other.provider.net proto pop2:
2303 user "John.Smith", with password "My^Hat", is "John.Smith" here;
2304 If you need to include whitespace in a parameter string or start the
2307 latter with a number, enclose the string in double quotes. Thus:
2308 poll mail.provider.net with proto pop3:
2311 user "jsmith" there has password "4u but u can't krak this"
2312 is jws here and wants mda "/bin/mail"
2313 You may have an initial server description headed by the keyword
2316 'defaults' instead of 'poll' followed by a name. Such a record is
2317 interpreted as defaults for all queries to use. It may be overwritten
2318 by individual server descriptions. So, you could write:
2319 defaults proto pop3
2322 user "jsmith"
2323 poll pop.provider.net
2324 pass "secret1"
2325 poll mail.provider.net
2326 user "jjsmith" there has password "secret2"
2327 It's possible to specify more than one user per server. The 'user'
2330 keyword leads off a user description, and every user specification in a
2331 multi-user entry must include it. Here's an example:
2332 poll pop.provider.net proto pop3 port 3111
2335 user "jsmith" with pass "secret1" is "smith" here
2336 user jones with pass "secret2" is "jjones" here keep
2337 This associates the local username 'smith' with the pop.provider.net
2340 username 'jsmith' and the local username 'jjones' with the
2341 pop.provider.net username 'jones'. Mail for 'jones' is kept on the
2342 server after download.
2343 Here's what a simple retrieval configuration for a multidrop mailbox
2346 looks like:
2347 poll pop.provider.net:
2350 user maildrop with pass secret1 to golux 'hurkle'='happy' snark here
2351 This says that the mailbox of account 'maildrop' on the server is a
2354 multidrop box, and that messages in it should be parsed for the server
2355 user names 'golux', 'hurkle', and 'snark'. It further specifies that
2356 'golux' and 'snark' have the same name on the client as on the server,
2357 but mail for server user 'hurkle' should be delivered to client user
2358 'happy'.
2359 Note that fetchmail, until version 6.3.4, did NOT allow full
2362 user@domain specifications here, these would never match. Fetchmail
2363 6.3.5 and newer support user@domain specifications on the left-hand
2364 side of a user mapping.
2365 Here's an example of another kind of multidrop connection:
2368 poll pop.provider.net localdomains loonytoons.org toons.org
2371 envelope X-Envelope-To
2372 user maildrop with pass secret1 to * here
2373 This also says that the mailbox of account 'maildrop' on the server is
2376 a multidrop box. It tells fetchmail that any address in the loony‐
2377 toons.org or toons.org domains (including sub-domain addresses like
2378 'joe@daffy.loonytoons.org') should be passed through to the local SMTP
2379 listener without modification. Be careful of mail loops if you do
2380 this!
2381 Here's an example configuration using ssh and the plugin option. The
2384 queries are made directly on the stdin and stdout of imapd via ssh.
2385 Note that in this setup, IMAP authentication can be skipped.
2386 poll mailhost.net with proto imap:
2389 plugin "ssh %h /usr/sbin/imapd" auth ssh;
2390 user esr is esr here
2391
2394 Use the multiple-local-recipients feature with caution -- it can bite.
2395 All multidrop features are ineffective in ETRN and ODMR modes.
2396 Also, note that in multidrop mode duplicate mails may be suppressed. A
2398 piece of mail is considered duplicate if it does not have a discernable
2399 envelope recipient address, has the same header as the message immedi‐
2400 ately preceding and more than one addressee. Such runs of messages may
2401 be generated when copies of a message addressed to multiple users are
2402 delivered to a multidrop box. (To be precise, fetchmail 6.2.5 through
2403 6.4.X use an MD5 hash of the raw message header, and only fetchmail
2404 6.4.16+ document this properly. Fetchmail 5.0.8 (1999-09-14) through
2405 6.2.4 used only the Message-ID header. 5.0.7 and older did not sup‐
2406 press duplicates.)
2407 Note that this duplication killer code checking the entire header is
2409 very restrictive and may not suppress many duplicates in practice - for
2410 instance, if some X-Original-To or Delivered-To header differs. This
2411 is intentional and correct in such situations: wherever envelope infor‐
2412 mation is available, it should be used for reliable delivery of mailing
2413 list and blind carbon copy (Bcc) messages. See the subsection Duplicate
2414 suppression below for suggestions.
2415 Header vs. Envelope addresses
2418 The fundamental problem is that by having your mailserver toss several
2419 peoples' mail in a single maildrop box, you may have thrown away poten‐
2420 tially vital information about who each piece of mail was actually
2421 addressed to (the 'envelope address', as opposed to the header
2422 addresses in the RFC822 To/Cc headers - the Bcc is not available at the
2423 receiving end). This 'envelope address' is the address you need in
2424 order to reroute mail properly.
2425 Sometimes fetchmail can deduce the envelope address. If the mailserver
2427 MTA is sendmail and the item of mail had just one recipient, the MTA
2428 will have written a 'by/for' clause that gives the envelope addressee
2429 into its Received header. But this doesn't work reliably for other
2430 MTAs, nor if there is more than one recipient. By default, fetchmail
2431 looks for envelope addresses in these lines; you can restore this
2432 default with -E "Received" or 'envelope Received'.
2433 As a better alternative, some SMTP listeners and/or mail servers insert
2435 a header in each message containing a copy of the envelope addresses.
2436 This header (when it exists) is often 'X-Original-To', 'Delivered-To'
2437 or 'X-Envelope-To'. Fetchmail's assumption about this can be changed
2438 with the -E or 'envelope' option. Note that writing an envelope header
2439 of this kind exposes the names of recipients (including blind-copy
2440 recipients) to all receivers of the messages, so the upstream must
2441 store one copy of the message per recipient to avoid becoming a privacy
2442 problem.
2443 Postfix, since version 2.0, writes an X-Original-To: header which con‐
2445 tains a copy of the envelope as it was received.
2446 Qmail and Postfix generally write a 'Delivered-To' header upon deliver‐
2448 ing the message to the mail spool and use it to avoid mail loops.
2449 Qmail virtual domains however will prefix the user name with a string
2450 that normally matches the user's domain. To remove this prefix you can
2451 use the -Q or 'qvirtual' option.
2452 Sometimes, unfortunately, neither of these methods works. That is the
2454 point when you should contact your ISP and ask them to provide such an
2455 envelope header, and you should not use multidrop in this situation.
2456 When they all fail, fetchmail must fall back on the contents of To/Cc
2457 headers (Bcc headers are not available - see below) to try to determine
2458 recipient addressees -- and these are unreliable. In particular, mail‐
2459 ing-list software often ships mail with only the list broadcast address
2460 in the To header.
2461 Note that a future version of fetchmail may remove To/Cc parsing!
2463 When fetchmail cannot deduce a recipient address that is local, and the
2465 intended recipient address was anyone other than fetchmail's invoking
2466 user, mail will get lost. This is what makes the multidrop feature
2467 risky without proper envelope information.
2468 A related problem is that when you blind-copy a mail message, the Bcc
2470 information is carried only as envelope address (it's removed from the
2471 headers by the sending mail server, so fetchmail can see it only if
2472 there is an X-Envelope-To header). Thus, blind-copying to someone who
2473 gets mail over a fetchmail multidrop link will fail unless the the
2474 mailserver host routinely writes X-Envelope-To or an equivalent header
2475 into messages in your maildrop.
2476 In conclusion, mailing lists and Bcc'd mail can only work if the server
2478 you're fetching from
2479 (1) stores one copy of the message per recipient in your domain and
2481 (2) records the envelope information in a special header (X-Origi‐
2483 nal-To, Delivered-To, X-Envelope-To).
2484 Good Ways To Use Multidrop Mailboxes
2487 Multiple local names can be used to administer a mailing list from the
2488 client side of a fetchmail collection. Suppose your name is 'esr', and
2489 you want to both pick up your own mail and maintain a mailing list
2490 called (say) "fetchmail-friends", and you want to keep the alias list
2491 on your client machine.
2492 On your server, you can alias 'fetchmail-friends' to 'esr'; then, in
2494 your .fetchmailrc, declare 'to esr fetchmail-friends here'. Then, when
2495 mail including 'fetchmail-friends' as a local address gets fetched, the
2496 list name will be appended to the list of recipients your SMTP listener
2497 sees. Therefore it will undergo alias expansion locally. Be sure to
2498 include 'esr' in the local alias expansion of fetchmail-friends, or
2499 you'll never see mail sent only to the list. Also be sure that your
2500 listener has the "me-too" option set (sendmail's -oXm command-line
2501 option or OXm declaration) so your name isn't removed from alias expan‐
2502 sions in messages you send.
2503 This trick is not without its problems, however. You'll begin to see
2505 this when a message comes in that is addressed only to a mailing list
2506 you do not have declared as a local name. Each such message will fea‐
2507 ture an 'X-Fetchmail-Warning' header which is generated because fetch‐
2508 mail cannot find a valid local name in the recipient addresses. Such
2509 messages default (as was described above) to being sent to the local
2510 user running fetchmail, but the program has no way to know that that's
2511 actually the right thing.
2512 Bad Ways To Abuse Multidrop Mailboxes
2515 Multidrop mailboxes and fetchmail serving multiple users in daemon mode
2516 do not mix. The problem, again, is mail from mailing lists, which typ‐
2517 ically does not have an individual recipient address on it. Unless
2518 fetchmail can deduce an envelope address, such mail will only go to the
2519 account running fetchmail (probably root). Also, blind-copied users
2520 are very likely never to see their mail at all.
2521 If you're tempted to use fetchmail to retrieve mail for multiple users
2523 from a single mail drop via POP or IMAP, think again (and reread the
2524 section on header and envelope addresses above). It would be smarter
2525 to just let the mail sit in the mailserver's queue and use fetchmail's
2526 ETRN or ODMR modes to trigger SMTP sends periodically (of course, this
2527 means you have to poll more frequently than the mailserver's expiry
2528 period). If you can't arrange this, try setting up a UUCP feed.
2529 If you absolutely must use multidrop for this purpose, make sure your
2531 mailserver writes an envelope-address header that fetchmail can see.
2532 Otherwise you will lose mail and it will come back to haunt you.
2533 Speeding Up Multidrop Checking
2536 Normally, when multiple users are declared fetchmail extracts recipient
2537 addresses as described above and checks each host part with DNS to see
2538 if it's an alias of the mailserver. If so, the name mappings described
2539 in the "to ... here" declaration are done and the mail locally deliv‐
2540 ered.
2541 This is a convenient but also slow method. To speed it up, pre-declare
2543 mailserver aliases with 'aka'; these are checked before DNS lookups are
2544 done. If you're certain your aka list contains all DNS aliases of the
2545 mailserver (and all MX names pointing at it - note this may change in a
2546 future version) you can declare 'no dns' to suppress DNS lookups
2547 entirely and only match against the aka list.
2548 Duplicate suppression on multidrop
2551 If fetchmail's duplicate suppression code does not kick in for your
2552 multidrop mail account, other options is using sieve, or for instance
2553 Courier's maildrop package (and in particular, its reformail program
2554 with the -D option) as the delivery agent (either from fetchmail, or
2555 from your local mail server that fetchmail injects into).
2556
2559 Support for socks4/5 is a compile time configuration option. Once com‐
2560 piled in, fetchmail will always use the socks libraries and configura‐
2561 tion on your system, there are no run-time switches in fetchmail - but
2562 you can still configure SOCKS: you can specify which SOCKS configura‐
2563 tion file is used in the SOCKS_CONF environment variable.
2564 For instance, if you wanted to bypass the SOCKS proxy altogether and
2566 have fetchmail connect directly, you could just pass
2567 SOCKS_CONF=/dev/null in the environment, for example (add your usual
2568 command line options - if any - to the end of this line):
2569 env SOCKS_CONF=/dev/null fetchmail
2571
2574 To facilitate the use of fetchmail in shell scripts, an exit status
2575 code is returned to give an indication of what occurred during a given
2576 connection.
2577 The exit codes returned by fetchmail are as follows:
2579 0 One or more messages were successfully retrieved (or, if the -c
2581 option was selected, were found waiting but not retrieved).
2582 1 There was no mail awaiting retrieval. (There may have been old
2584 mail still on the server but not selected for retrieval.) If you
2585 do not want "no mail" to be an error condition (for instance,
2586 for cron jobs), use a POSIX-compliant shell and add
2587 || [ $? -eq 1 ]
2589 to the end of the fetchmail command line, note that this leaves
2591 0 untouched, maps 1 to 0, and maps all other codes to 1. See
2592 also item #C8 in the FAQ.
2593 2 An error was encountered when attempting to open a socket to
2595 retrieve mail. If you don't know what a socket is, don't worry
2596 about it -- just treat this as an 'unrecoverable error'. This
2597 error can also be because a protocol fetchmail wants to use is
2598 not listed in /etc/services.
2599 3 The user authentication step failed. This usually means that a
2601 bad user-id, password, or APOP id was specified. Or it may mean
2602 that you tried to run fetchmail under circumstances where it did
2603 not have standard input attached to a terminal and could not
2604 prompt for a missing password.
2605 4 Some sort of fatal protocol error was detected.
2607 5 There was a syntax error in the arguments to fetchmail, or a
2609 pre- or post-connect command failed.
2610 6 The run control file had bad permissions.
2612 7 There was an error condition reported by the server. Can also
2614 fire if fetchmail timed out while waiting for the server.
2615 8 Client-side exclusion error. This means fetchmail either found
2617 another copy of itself already running, or failed in such a way
2618 that it isn't sure whether another copy is running.
2619 9 The user authentication step failed because the server responded
2621 "lock busy". Try again after a brief pause! This error is not
2622 implemented for all protocols, nor for all servers. If not
2623 implemented for your server, "3" will be returned instead, see
2624 above. May be returned when talking to qpopper or other servers
2625 that can respond with "lock busy" or some similar text contain‐
2626 ing the word "lock".
2627 10 The fetchmail run failed while trying to do an SMTP port open or
2629 transaction.
2630 11 Fatal DNS error. Fetchmail encountered an error while perform‐
2632 ing a DNS lookup at startup and could not proceed.
2633 12 BSMTP batch file could not be opened.
2635 13 Poll terminated by a fetch limit (see the --fetchlimit option).
2637 14 Server busy indication.
2639 23 Internal error. You should see a message on standard error with
2641 details.
2642 24 - 26, 28, 29
2644 These are internal codes and should not appear externally.
2645 When fetchmail queries more than one host, return status is 0 if any
2647 query successfully retrieved mail. Otherwise the returned error status
2648 is that of the last host queried.
2649
2652 ~/.fetchmailrc, $HOME/.fetchmailrc, $HOME_ETC/.fetchmailrc, $FETCHMAIL‐
2653 HOME/fetchmailrc
2654 default run control file (location can be overridden with environ‐
2655 ment variables)
2656 ~/.fetchids, $HOME/.fetchids, $HOME_ETC/.fetchids, $FETCHMAIL‐
2658 HOME/.fetchids
2659 default location of file recording last message UIDs seen per
2660 host. (location can be overridden with environment variables)
2661 ~/.fetchmail.pid, $HOME/.fetchmail.pid, $HOME_ETC/.fetchmail.pid,
2663 $FETCHMAILHOME/fetchmail.pid
2664 default location of lock file (sometimes called pidfile or PID
2665 file, see option pidfile) to help prevent concurrent runs (non-
2666 root mode). (location can be overridden with environment vari‐
2667 ables)
2668 ~/.netrc, $HOME/.netrc, $HOME_ETC/.netrc
2670 your FTP run control file, which (if present) will be searched for
2671 passwords as a last resort before prompting for one interactively.
2672 (location can be overridden with environment variables)
2673 /var/run/fetchmail.pid
2675 lock file (pidfile) to help prevent concurrent runs (root mode,
2676 Linux systems).
2677 /etc/fetchmail.pid
2679 lock file (pidfile) to help prevent concurrent runs (root mode,
2680 systems without /var/run).
2681
2684 Fetchmail's behavior can be altered by providing it with environment
2685 variables. Some may alter the operation of libraries that fetchmail
2686 links against, for instance, OpenSSL. Note that in daemon mode, you
2687 will need to quit the background daemon process and start a new fetch‐
2688 mail daemon for environment changes to take effect.
2689 FETCHMAILHOME
2691 If this environment variable is set to a valid and existing
2692 directory name, fetchmail will read $FETCHMAILHOME/fetchmailrc
2693 (the dot is missing in this case), $FETCHMAILHOME/.fetchids
2694 (keeping its dot) and $FETCHMAILHOME/fetchmail.pid (without dot)
2695 rather than from the user's home directory. The .netrc file is
2696 always looked for in the the invoking user's home directory (or
2697 $HOME_ETC) regardless of FETCHMAILHOME's setting.
2698 FETCHMAILUSER
2701 If this environment variable is set, it is used as the name of
2702 the calling user (default local name) for purposes such as mail‐
2703 ing error notifications. Otherwise, if either the LOGNAME or
2704 USER variable is correctly set (e.g. the corresponding UID
2705 matches the session user ID) then that name is used as the
2706 default local name. Otherwise getpwuid(3) must be able to
2707 retrieve a password entry for the session ID (this elaborate
2708 logic is designed to handle the case of multiple names per
2709 userid gracefully).
2710 FETCHMAIL_DISABLE_CBC_IV_COUNTERMEASURE
2713 (since v6.3.22): If this environment variable is set and not
2714 empty, fetchmail will disable a countermeasure against an SSL
2715 CBC IV attack (by setting SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS).
2716 This is a security risk, but may be necessary for connecting to
2717 certain non-standards-conforming servers. See fetchmail's NEWS
2718 file and fetchmail-SA-2012-01.txt for details. Earlier fetch‐
2719 mail versions (v6.3.21 and older) used to disable this counter‐
2720 measure, but v6.3.22 no longer does that as a safety precaution.
2721 FETCHMAIL_POP3_FORCE_RETR
2724 (since v6.3.9): If this environment variable is defined at all
2725 (even if empty), fetchmail will forgo the POP3 TOP command and
2726 always use RETR. This can be used as a workaround when TOP does
2727 not work properly.
2728 FETCHMAIL_INCLUDE_DEFAULT_X509_CA_CERTS
2731 (since v6.3.17): If this environment variable is set and not
2732 empty, fetchmail will always load the default X.509 trusted cer‐
2733 tificate locations for SSL/TLS CA certificates, even if
2734 --sslcertfile and --sslcertpath are given. The latter locations
2735 take precedence over the system default locations. This is use‐
2736 ful in case there are broken certificates in the system directo‐
2737 ries and the user has no administrator privileges to remedy the
2738 problem.
2739 HOME (documented since 6.4.1): This variable is nomally set to the
2742 user's home directory. If it is set to a different directory
2743 than what is in the password database, HOME takes precedence.
2744 HOME_ETC
2747 (documentation corrected to match behaviour code since 6.4.1):
2748 If the HOME_ETC variable is set, it will override fetchmail's
2749 idea of $HOME, i. e. fetchmail will read .fetchmailrc,
2750 .fetchids, .fetchmail.pid and .netrc from $HOME_ETC instead of
2751 $HOME (or if HOME is also unset, from the passwd file's home
2752 directory location).
2753 If HOME_ETC and FETCHMAILHOME are both set, FETCHMAILHOME takes
2755 prececence and HOME_ETC will be ignored.
2756 SOCKS_CONF
2759 (only if SOCKS support is compiled in) this variable is used by
2760 the socks library to find out which configuration file it should
2761 read. Set this to /dev/null to bypass the SOCKS proxy.
2762 SSL_CERT_DIR
2765 (with truly OpenSSL 1.1.1 compatible library): overrides
2766 OpenSSL's idea of the default trust directory or path (which
2767 contains individual certificate files and hashed symlinks), see
2768 the SSL_CTX_set_default_verify_paths(3) manual page for details,
2769 it may be in the openssl development package. If using another
2770 library's OpenSSL compatibility interface, this may not work.
2771 Since this variable only specifies a default value, the option
2772 --sslcertpath takes precedence if given.
2773 SSL_CERT_FILE
2776 (with truly OpenSSL 1.1.1 compatible library): overrides
2777 OpenSSL's idea of the default trust certificate bundle file
2778 (which contains a concatenation of base64-encoded certificates
2779 in PEM format), see the SSL_CTX_set_default_verify_paths(3) man‐
2780 ual page for details, it may be in the openssl development pack‐
2781 age. If using another library's OpenSSL compatibility inter‐
2782 face, this may not work. Since this variable only specifies a
2783 default value, the option --sslcertfile takes precedence if
2784 given.
2785
2788 If a fetchmail daemon is running as root, SIGUSR1 wakes it up from its
2789 sleep phase and forces a poll of all non-skipped servers. For compati‐
2790 bility reasons, SIGHUP can also be used in 6.3.X but may not be avail‐
2791 able in future fetchmail versions.
2792 If fetchmail is running in daemon mode as non-root, use SIGUSR1 to wake
2794 it (this is so SIGHUP due to logout can retain the default action of
2795 killing it).
2796 Running fetchmail in foreground while a background fetchmail is running
2798 will do whichever of these is appropriate to wake it up.
2799
2802 Please check the NEWS file that shipped with fetchmail for more known
2803 bugs than those listed here.
2804 Fetchmail cannot handle user names that contain blanks after a "@"
2806 character, for instance "demonstr@ti on". These are rather uncommon and
2807 only hurt when using UID-based --keep setups, so the 6.3.X versions of
2808 fetchmail won't be fixed.
2809 Fetchmail cannot handle configurations where you have multiple accounts
2811 that use the same server name and the same login. Any user@server com‐
2812 bination must be unique.
2813 The assumptions that the DNS and in particular the checkalias options
2815 make are not often sustainable. For instance, it has become uncommon
2816 for an MX server to be a POP3 or IMAP server at the same time. There‐
2817 fore the MX lookups may go away in a future release.
2818 The mda and plugin options interact badly. In order to collect error
2820 status from the MDA, fetchmail has to change its normal signal handling
2821 so that dead plugin processes don't get reaped until the end of the
2822 poll cycle. This can cause resource starvation if too many zombies
2823 accumulate. So either don't deliver to a MDA using plugins or risk
2824 being overrun by an army of undead.
2825 The --interface option does not support IPv6 and it is doubtful if it
2827 ever will, since there is no portable way to query interface IPv6
2828 addresses.
2829 The RFC822 address parser used in multidrop mode chokes on some
2831 @-addresses that are technically legal but bizarre. Strange uses of
2832 quoting and embedded comments are likely to confuse it.
2833 In a message with multiple envelope headers, only the last one pro‐
2835 cessed will be visible to fetchmail.
2836 Use of some of these protocols requires that the program send unen‐
2838 crypted passwords over the TCP/IP connection to the mailserver. This
2839 creates a risk that name/password pairs might be snaffled with a packet
2840 sniffer or more sophisticated monitoring software. Under Linux and
2841 FreeBSD, the --interface option can be used to restrict polling to
2842 availability of a specific interface device with a specific local or
2843 remote IP address, but snooping is still possible if (a) either host
2844 has a network device that can be opened in promiscuous mode, or (b) the
2845 intervening network link can be tapped. We recommend the use of ssh(1)
2846 tunnelling to not only shroud your passwords but encrypt the entire
2847 conversation.
2848 Use of the %F or %T escapes in an mda option could open a security
2850 hole, because they pass text manipulable by an attacker to a shell com‐
2851 mand. Potential shell characters are replaced by '_' before execution.
2852 The hole is further reduced by the fact that fetchmail temporarily dis‐
2853 cards any suid privileges it may have while running the MDA. For maxi‐
2854 mum safety, however, don't use an mda command containing %F or %T when
2855 fetchmail is run from the root account itself.
2856 Fetchmail's method of sending bounces due to errors or spam-blocking
2858 and spam bounces requires that port 25 of localhost be available for
2859 sending mail via SMTP.
2860 If you modify ~/.fetchmailrc while a background instance is running and
2862 break the syntax, the background instance will die silently. Unfortu‐
2863 nately, it can't die noisily because we don't yet know whether syslog
2864 should be enabled. On some systems, fetchmail dies quietly even if
2865 there is no syntax error; this seems to have something to do with buggy
2866 terminal ioctl code in the kernel.
2867 The -f - option (reading a configuration from stdin) is incompatible
2869 with the plugin option.
2870 The 'principal' option only handles Kerberos IV, not V.
2872 Interactively entered passwords are truncated after 63 characters. If
2874 you really need to use a longer password, you will have to use a con‐
2875 figuration file.
2876 A backslash as the last character of a configuration file will be
2878 flagged as a syntax error rather than ignored.
2879 The BSMTP error handling is virtually nonexistent and may leave broken
2881 messages behind.
2882 Send comments, bug reports, gripes, and the like to the fetchmail-devel
2884 list ⟨fetchmail-devel@lists.sourceforge.net⟩
2885 An HTML FAQ ⟨https://fetchmail.sourceforge.io/fetchmail-FAQ.html⟩ is
2888 available at the fetchmail home page, it should also accompany your
2889 installation.
2890
2893 Fetchmail is currently maintained by Matthias Andree and Rob Funk with
2894 major assistance from Sunil Shetye (for code) and Rob MacGregor (for
2895 the mailing lists).
2896 Most of the code is from Eric S. Raymond ⟨esr@snark.thyrsus.com⟩ . Too
2898 many other people to name here have contributed code and patches.
2899 This program is descended from and replaces popclient, by Carl Harris
2901 ⟨ceharris@mal.com⟩ ; the internals have become quite different, but
2902 some of its interface design is directly traceable to that ancestral
2903 program.
2904 This manual page has been improved by Matthias Andree, R. Hannes Bein‐
2906 ert, and Héctor García.
2907
2910 README, README.SSL, README.SSL-SERVER, The Fetchmail FAQ ⟨https://
2911 www.fetchmail.info/fetchmail-FAQ.html⟩, mutt(1), elm(1), mail(1), send‐
2912 mail(8), popd(8), imapd(8), netrc(5).
2913 The fetchmail home page. ⟨https://www.fetchmail.info/⟩
2915 The fetchmail home page (alternative URI). ⟨https://
2917 fetchmail.sourceforge.io/⟩
2918 The maildrop home page. ⟨https://www.courier-mta.org/maildrop/⟩
2920
2922 Note that this list is just a collection of references and not a state‐
2923 ment as to the actual protocol conformance or requirements in fetch‐
2924 mail.
2925 SMTP/ESMTP:
2927 RFC 821, RFC 2821, RFC 1869, RFC 1652, RFC 1870, RFC 1983, RFC
2928 1985, RFC 2554.
2929 mail:
2931 RFC 822, RFC 2822, RFC 1123, RFC 1892, RFC 1894.
2932 POP2:
2934 RFC 937
2935 POP3:
2937 RFC 1081, RFC 1225, RFC 1460, RFC 1725, RFC 1734, RFC 1939, RFC
2938 1957, RFC 2195, RFC 2449.
2939 APOP:
2941 RFC 1939.
2942 RPOP:
2944 RFC 1081, RFC 1225.
2945 IMAP2/IMAP2BIS:
2947 RFC 1176, RFC 1732.
2948 IMAP4/IMAP4rev1:
2950 RFC 1730, RFC 1731, RFC 1732, RFC 2060, RFC 2061, RFC 2195, RFC
2951 2177, RFC 2683.
2952 ETRN:
2954 RFC 1985.
2955 ODMR/ATRN:
2957 RFC 2645.
2958 OTP: RFC 1938.
2960 LMTP:
2962 RFC 2033.
2963 GSSAPI:
2965 RFC 1508, RFC 1734, Generic Security Service Application Program
2966 Interface (GSSAPI)/Kerberos/Simple Authentication and Security
2967 Layer (SASL) Service Names ⟨https://www.iana.org/assignments/
2968 gssapi-service-names/⟩.
2969 TLS: RFC 2595.
2971fetchmail 6.4.16 2021-01-30 fetchmail(1)