1SENDMAIL(8) System Manager's Manual SENDMAIL(8)
2
6 sendmail - an electronic mail transport agent
7
9 sendmail [flags] [address ...]
10 newaliases
11 mailq [-v]
12 hoststat
13 purgestat
14 smtpd
15
17 Sendmail sends a message to one or more recipients, routing the message
18 over whatever networks are necessary. Sendmail does internetwork for‐
19 warding as necessary to deliver the message to the correct place.
20 Sendmail is not intended as a user interface routine; other programs
22 provide user-friendly front ends; sendmail is used only to deliver pre-
23 formatted messages.
24 With no flags, sendmail reads its standard input up to an end-of-file
26 or a line consisting only of a single dot and sends a copy of the mes‐
27 sage found there to all of the addresses listed. It determines the
28 network(s) to use based on the syntax and contents of the addresses.
29 Local addresses are looked up in a file and aliased appropriately.
31 Aliasing can be prevented by preceding the address with a backslash.
32 Beginning with 8.10, the sender is included in any alias expansions,
33 e.g., if `john' sends to `group', and `group' includes `john' in the
34 expansion, then the letter will also be delivered to `john'.
35 Parameters
37 -Ac Use submit.cf even if the operation mode does not indicate an
38 initial mail submission.
39 -Am Use sendmail.cf even if the operation mode indicates an initial
41 mail submission.
42 -Btype Set the body type to type. Current legal values are 7BIT or
44 8BITMIME.
45 -ba Go into ARPANET mode. All input lines must end with a CR-LF,
47 and all messages will be generated with a CR-LF at the end.
48 Also, the ``From:'' and ``Sender:'' fields are examined for the
49 name of the sender.
50 -bC Check the configuration file.
52 -bd Run as a daemon. Sendmail will fork and run in background lis‐
54 tening on socket 25 for incoming SMTP connections. This is nor‐
55 mally run from /etc/rc.
56 -bD Same as -bd except runs in foreground.
58 -bh Print the persistent host status database.
60 -bH Purge expired entries from the persistent host status database.
62 -bi Initialize the alias database.
64 -bm Deliver mail in the usual way (default).
66 -bp Print a listing of the queue(s).
68 -bP Print number of entries in the queue(s); only available with
70 shared memory support.
71 -bs Use the SMTP protocol as described in RFC821 on standard input
73 and output. This flag implies all the operations of the -ba
74 flag that are compatible with SMTP.
75 -bt Run in address test mode. This mode reads addresses and shows
77 the steps in parsing; it is used for debugging configuration
78 tables.
79 -bv Verify names only - do not try to collect or deliver a message.
81 Verify mode is normally used for validating users or mailing
82 lists.
83 -Cfile Use alternate configuration file. Sendmail gives up any
85 enhanced (set-user-ID or set-group-ID) privileges if an alter‐
86 nate configuration file is specified.
87 -D logfile
89 Send debugging output to the indicated log file instead of std‐
90 out.
91 -dcategory.level...
93 Set the debugging flag for category to level. Category is
94 either an integer or a name specifying the topic, and level an
95 integer specifying the level of debugging output desired.
96 Higher levels generally mean more output. More than one flag
97 can be specified by separating them with commas. A list of
98 numeric debugging categories can be found in the TRACEFLAGS file
99 in the sendmail source distribution.
100 The option -d0.1 prints the version of sendmail and the options
101 it was compiled with.
102 Most other categories are only useful with, and documented in,
103 sendmail's source code.
104 -Ffullname
106 Set the full name of the sender.
107 -fname Sets the name of the ``from'' person (i.e., the envelope sender
109 of the mail). This address may also be used in the From: header
110 if that header is missing during initial submission. The enve‐
111 lope sender address is used as the recipient for delivery status
112 notifications and may also appear in a Return-Path: header. -f
113 should only be used by ``trusted'' users (normally root, daemon,
114 and network) or if the person you are trying to become is the
115 same as the person you are. Otherwise, an X-Authentication-
116 Warning header will be added to the message.
117 -G Relay (gateway) submission of a message, e.g., when rmail calls
119 sendmail .
120 -hN Set the hop count to N. The hop count is incremented every time
122 the mail is processed. When it reaches a limit, the mail is
123 returned with an error message, the victim of an aliasing loop.
124 If not specified, ``Received:'' lines in the message are
125 counted.
126 -i Do not strip a leading dot from lines in incoming messages, and
128 do not treat a dot on a line by itself as the end of an incoming
129 message. This should be set if you are reading data from a
130 file.
131 -L tag Set the identifier used in syslog messages to the supplied tag.
133 -N dsn Set delivery status notification conditions to dsn, which can be
135 `never' for no notifications or a comma separated list of the
136 values `failure' to be notified if delivery failed, `delay' to
137 be notified if delivery is delayed, and `success' to be notified
138 when the message is successfully delivered.
139 -n Don't do aliasing.
141 -O option=value
143 Set option option to the specified value. This form uses long
144 names. See below for more details.
145 -ox value
147 Set option x to the specified value. This form uses single
148 character names only. The short names are not described in this
149 manual page; see the Sendmail Installation and Operation Guide
150 for details.
151 -pprotocol
153 Set the name of the protocol used to receive the message. This
154 can be a simple protocol name such as ``UUCP'' or a protocol and
155 hostname, such as ``UUCP:ucbvax''.
156 -q[time]
158 Process saved messages in the queue at given intervals. If time
159 is omitted, process the queue once. Time is given as a tagged
160 number, with `s' being seconds, `m' being minutes (default), `h'
161 being hours, `d' being days, and `w' being weeks. For example,
162 `-q1h30m' or `-q90m' would both set the timeout to one hour
163 thirty minutes. By default, sendmail will run in the back‐
164 ground. This option can be used safely with -bd.
165 -qp[time]
167 Similar to -qtime, except that instead of periodically forking a
168 child to process the queue, sendmail forks a single persistent
169 child for each queue that alternates between processing the
170 queue and sleeping. The sleep time is given as the argument; it
171 defaults to 1 second. The process will always sleep at least 5
172 seconds if the queue was empty in the previous queue run.
173 -qf Process saved messages in the queue once and do not fork(), but
175 run in the foreground.
176 -qGname
178 Process jobs in queue group called name only.
179 -q[!]Isubstr
181 Limit processed jobs to those containing substr as a substring
182 of the queue id or not when ! is specified.
183 -q[!]Qsubstr
185 Limit processed jobs to quarantined jobs containing substr as a
186 substring of the quarantine reason or not when ! is specified.
187 -q[!]Rsubstr
189 Limit processed jobs to those containing substr as a substring
190 of one of the recipients or not when ! is specified.
191 -q[!]Ssubstr
193 Limit processed jobs to those containing substr as a substring
194 of the sender or not when ! is specified.
195 -Q[reason]
197 Quarantine a normal queue items with the given reason or unquar‐
198 antine quarantined queue items if no reason is given. This
199 should only be used with some sort of item matching using as
200 described above.
201 -R return
203 Set the amount of the message to be returned if the message
204 bounces. The return parameter can be `full' to return the
205 entire message or `hdrs' to return only the headers. In the
206 latter case also local bounces return only the headers.
207 -rname An alternate and obsolete form of the -f flag.
209 -t Read message for recipients. To:, Cc:, and Bcc: lines will be
211 scanned for recipient addresses. The Bcc: line will be deleted
212 before transmission.
213 -V envid
215 Set the original envelope id. This is propagated across SMTP to
216 servers that support DSNs and is returned in DSN-compliant error
217 messages.
218 -v Go into verbose mode. Alias expansions will be announced, etc.
220 -X logfile
222 Log all traffic in and out of mailers in the indicated log file.
223 This should only be used as a last resort for debugging mailer
224 bugs. It will log a lot of data very quickly.
225 -- Stop processing command flags and use the rest of the arguments
227 as addresses.
228 Options
230 There are also a number of processing options that may be set. Nor‐
231 mally these will only be used by a system administrator. Options may
232 be set either on the command line using the -o flag (for short names),
233 the -O flag (for long names), or in the configuration file. This is a
234 partial list limited to those options that are likely to be useful on
235 the command line and only shows the long names; for a complete list
236 (and details), consult the Sendmail Installation and Operation Guide.
237 The options are:
238 AliasFile=file
240 Use alternate alias file.
241 HoldExpensive
243 On mailers that are considered ``expensive'' to connect to,
244 don't initiate immediate connection. This requires queueing.
245 CheckpointInterval=N
247 Checkpoint the queue file after every N successful deliveries
248 (default 10). This avoids excessive duplicate deliveries when
249 sending to long mailing lists interrupted by system crashes.
250 DeliveryMode=x
252 Set the delivery mode to x. Delivery modes are `i' for interac‐
253 tive (synchronous) delivery, `b' for background (asynchronous)
254 delivery, `q' for queue only - i.e., actual delivery is done the
255 next time the queue is run, and `d' for deferred - the same as
256 `q' except that database lookups for maps which have set the -D
257 option (default for the host map) are avoided.
258 ErrorMode=x
260 Set error processing to mode x. Valid modes are `m' to mail
261 back the error message, `w' to ``write'' back the error message
262 (or mail it back if the sender is not logged in), `p' to print
263 the errors on the terminal (default), `q' to throw away error
264 messages (only exit status is returned), and `e' to do special
265 processing for the BerkNet. If the text of the message is not
266 mailed back by modes `m' or `w' and if the sender is local to
267 this machine, a copy of the message is appended to the file
268 dead.letter in the sender's home directory.
269 SaveFromLine
271 Save UNIX-style From lines at the front of messages.
272 MaxHopCount=N
274 The maximum number of times a message is allowed to ``hop''
275 before we decide it is in a loop.
276 IgnoreDots
278 Do not take dots on a line by themselves as a message termina‐
279 tor.
280 SendMimeErrors
282 Send error messages in MIME format. If not set, the DSN (Deliv‐
283 ery Status Notification) SMTP extension is disabled.
284 ConnectionCacheTimeout=timeout
286 Set connection cache timeout.
287 ConnectionCacheSize=N
289 Set connection cache size.
290 LogLevel=n
292 The log level.
293 MeToo=False
295 Don't send to ``me'' (the sender) if I am in an alias expansion.
296 CheckAliases
298 Validate the right hand side of aliases during a newaliases(1)
299 command.
300 OldStyleHeaders
302 If set, this message may have old style headers. If not set,
303 this message is guaranteed to have new style headers (i.e., com‐
304 mas instead of spaces between addresses). If set, an adaptive
305 algorithm is used that will correctly determine the header for‐
306 mat in most cases.
307 QueueDirectory=queuedir
309 Select the directory in which to queue messages.
310 StatusFile=file
312 Save statistics in the named file.
313 Timeout.queuereturn=time
315 Set the timeout on undelivered messages in the queue to the
316 specified time. After delivery has failed (e.g., because of a
317 host being down) for this amount of time, failed messages will
318 be returned to the sender. The default is five days.
319 UserDatabaseSpec=userdatabase
321 If set, a user database is consulted to get forwarding informa‐
322 tion. You can consider this an adjunct to the aliasing mecha‐
323 nism, except that the database is intended to be distributed;
324 aliases are local to a particular host. This may not be avail‐
325 able if your sendmail does not have the USERDB option compiled
326 in.
327 ForkEachJob
329 Fork each job during queue runs. May be convenient on memory-
330 poor machines.
331 SevenBitInput
333 Strip incoming messages to seven bits.
334 EightBitMode=mode
336 Set the handling of eight bit input to seven bit destinations to
337 mode: m (mimefy) will convert to seven-bit MIME format, p (pass)
338 will pass it as eight bits (but violates protocols), and s
339 (strict) will bounce the message.
340 MinQueueAge=timeout
342 Sets how long a job must ferment in the queue between attempts
343 to send it.
344 DefaultCharSet=charset
346 Sets the default character set used to label 8-bit data that is
347 not otherwise labelled.
348 DialDelay=sleeptime
350 If opening a connection fails, sleep for sleeptime seconds and
351 try again. Useful on dial-on-demand sites.
352 NoRecipientAction=action
354 Set the behaviour when there are no recipient headers (To:, Cc:
355 or Bcc:) in the message to action: none leaves the message
356 unchanged, add-to adds a To: header with the envelope recipi‐
357 ents, add-apparently-to adds an Apparently-To: header with the
358 envelope recipients, add-bcc adds an empty Bcc: header, and add-
359 to-undisclosed adds a header reading `To: undisclosed-recipi‐
360 ents:;'.
361 MaxDaemonChildren=N
363 Sets the maximum number of children that an incoming SMTP daemon
364 will allow to spawn at any time to N.
365 ConnectionRateThrottle=N
367 Sets the maximum number of connections per second to the SMTP
368 port to N.
369 In aliases, the first character of a name may be a vertical bar to
371 cause interpretation of the rest of the name as a command to pipe the
372 mail to. It may be necessary to quote the name to keep sendmail from
373 suppressing the blanks from between arguments. For example, a common
374 alias is:
375 msgs: "|/usr/bin/msgs -s"
377 Aliases may also have the syntax ``:include:filename'' to ask sendmail
379 to read the named file for a list of recipients. For example, an alias
380 such as:
381 poets: ":include:/usr/local/lib/poets.list"
383 would read /usr/local/lib/poets.list for the list of addresses making
385 up the group.
386 Sendmail returns an exit status describing what it did. The codes are
388 defined in <sysexits.h>:
389 EX_OK Successful completion on all addresses.
391 EX_NOUSER
393 User name not recognized.
394 EX_UNAVAILABLE
396 Catchall meaning necessary resources were not available.
397 EX_SYNTAX
399 Syntax error in address.
400 EX_SOFTWARE
402 Internal software error, including bad arguments.
403 EX_OSERR
405 Temporary operating system error, such as ``cannot fork''.
406 EX_NOHOST
408 Host name not recognized.
409 EX_TEMPFAIL
411 Message could not be sent immediately, but was queued.
412 If invoked as newaliases, sendmail will rebuild the alias database. If
414 invoked as mailq, sendmail will print the contents of the mail queue.
415 If invoked as hoststat, sendmail will print the persistent host status
416 database. If invoked as purgestat, sendmail will purge expired entries
417 from the persistent host status database. If invoked as smtpd, send‐
418 mail will act as a daemon, as if the -bd option were specified.
419
421 sendmail often gets blamed for many problems that are actually the
422 result of other problems, such as overly permissive modes on directo‐
423 ries. For this reason, sendmail checks the modes on system directories
424 and files to determine if they can be trusted. Although these checks
425 can be turned off and your system security reduced by setting the Dont‐
426 BlameSendmail option, the permission problems should be fixed. For
427 more information, see:
428 http://www.sendmail.org/tips/DontBlameSendmail.html
430
432 Except for the file /etc/mail/sendmail.cf itself the following path‐
433 names are all specified in /etc/mail/sendmail.cf. Thus, these values
434 are only approximations.
435 /etc/aliases
437 raw data for alias names
438 /etc/aliases.db
440 data base of alias names
441 /etc/mail/sendmail.cf
443 configuration file
444 /etc/mail/helpfile
446 help file
447 /var/log/mail/statistics
449 collected statistics
450 /var/spool/mqueue/*
452 temp files
453
455 mail(1), rmail(1), syslog(3), aliases(5), mailaddr(7),
456 DARPA Internet Request For Comments RFC819, RFC821, RFC822. Sendmail
458 Installation and Operation Guide, No. 8, SMM.
459 http://www.sendmail.org/
461 US Patent Numbers 6865671, 6986037.
463
465 The sendmail command appeared in 4.2BSD.
466 $Date: 2013-11-22 20:51:56 $ SENDMAIL(8)