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 -bd Run as a daemon. Sendmail will fork and run in background lis‐
52 tening on socket 25 for incoming SMTP connections. This is nor‐
53 mally run from /etc/rc.
54 -bD Same as -bd except runs in foreground.
56 -bh Print the persistent host status database.
58 -bH Purge expired entries from the persistent host status database.
60 -bi Initialize the alias database.
62 -bm Deliver mail in the usual way (default).
64 -bp Print a listing of the queue(s).
66 -bP Print number of entries in the queue(s); only available with
68 shared memory support.
69 -bs Use the SMTP protocol as described in RFC821 on standard input
71 and output. This flag implies all the operations of the -ba
72 flag that are compatible with SMTP.
73 -bt Run in address test mode. This mode reads addresses and shows
75 the steps in parsing; it is used for debugging configuration
76 tables.
77 -bv Verify names only - do not try to collect or deliver a message.
79 Verify mode is normally used for validating users or mailing
80 lists.
81 -Cfile Use alternate configuration file. Sendmail gives up any
83 enhanced (set-user-ID or set-group-ID) privileges if an alter‐
84 nate configuration file is specified.
85 -D logfile
87 Send debugging output to the indicated log file instead of std‐
88 out.
89 -dcategory.level...
91 Set the debugging flag for category to level. Category is
92 either an integer or a name specifying the topic, and level an
93 integer specifying the level of debugging output desired.
94 Higher levels generally mean more output. More than one flag
95 can be specified by separating them with commas. A list of
96 numeric debugging categories can be found in the TRACEFLAGS file
97 in the sendmail source distribution.
98 The option -d0.1 prints the version of sendmail and the options
99 it was compiled with.
100 Most other categories are only useful with, and documented in,
101 sendmail's source code.
102 -Ffullname
104 Set the full name of the sender.
105 -fname Sets the name of the ``from'' person (i.e., the envelope sender
107 of the mail). This address may also be used in the From: header
108 if that header is missing during initial submission. The enve‐
109 lope sender address is used as the recipient for delivery status
110 notifications and may also appear in a Return-Path: header. -f
111 should only be used by ``trusted'' users (normally root, daemon,
112 and network) or if the person you are trying to become is the
113 same as the person you are. Otherwise, an X-Authentication-
114 Warning header will be added to the message.
115 -G Relay (gateway) submission of a message, e.g., when rmail calls
117 sendmail .
118 -hN Set the hop count to N. The hop count is incremented every time
120 the mail is processed. When it reaches a limit, the mail is
121 returned with an error message, the victim of an aliasing loop.
122 If not specified, ``Received:'' lines in the message are
123 counted.
124 -i Ignore dots alone on lines by themselves in incoming messages.
126 This should be set if you are reading data from a file.
127 -L tag Set the identifier used in syslog messages to the supplied tag.
129 -N dsn Set delivery status notification conditions to dsn, which can be
131 `never' for no notifications or a comma separated list of the
132 values `failure' to be notified if delivery failed, `delay' to
133 be notified if delivery is delayed, and `success' to be notified
134 when the message is successfully delivered.
135 -n Don't do aliasing.
137 -O option=value
139 Set option option to the specified value. This form uses long
140 names. See below for more details.
141 -ox value
143 Set option x to the specified value. This form uses single
144 character names only. The short names are not described in this
145 manual page; see the Sendmail Installation and Operation Guide
146 for details.
147 -pprotocol
149 Set the name of the protocol used to receive the message. This
150 can be a simple protocol name such as ``UUCP'' or a protocol and
151 hostname, such as ``UUCP:ucbvax''.
152 -q[time]
154 Process saved messages in the queue at given intervals. If time
155 is omitted, process the queue once. Time is given as a tagged
156 number, with `s' being seconds, `m' being minutes (default), `h'
157 being hours, `d' being days, and `w' being weeks. For example,
158 `-q1h30m' or `-q90m' would both set the timeout to one hour
159 thirty minutes. By default, sendmail will run in the back‐
160 ground. This option can be used safely with -bd.
161 -qp[time]
163 Similar to -qtime, except that instead of periodically forking a
164 child to process the queue, sendmail forks a single persistent
165 child for each queue that alternates between processing the
166 queue and sleeping. The sleep time is given as the argument; it
167 defaults to 1 second. The process will always sleep at least 5
168 seconds if the queue was empty in the previous queue run.
169 -qf Process saved messages in the queue once and do not fork(), but
171 run in the foreground.
172 -qG name
174 Process jobs in queue group called name only.
175 -q[!]Isubstr
177 Limit processed jobs to those containing substr as a substring
178 of the queue id or not when ! is specified.
179 -q[!]Qsubstr
181 Limit processed jobs to quarantined jobs containing substr as a
182 substring of the quarantine reason or not when ! is specified.
183 -q[!]Rsubstr
185 Limit processed jobs to those containing substr as a substring
186 of one of the recipients or not when ! is specified.
187 -q[!]Ssubstr
189 Limit processed jobs to those containing substr as a substring
190 of the sender or not when ! is specified.
191 -Q[reason]
193 Quarantine a normal queue items with the given reason or unquar‐
194 antine quarantined queue items if no reason is given. This
195 should only be used with some sort of item matching using as
196 described above.
197 -R return
199 Set the amount of the message to be returned if the message
200 bounces. The return parameter can be `full' to return the
201 entire message or `hdrs' to return only the headers. In the
202 latter case also local bounces return only the headers.
203 -rname An alternate and obsolete form of the -f flag.
205 -t Read message for recipients. To:, Cc:, and Bcc: lines will be
207 scanned for recipient addresses. The Bcc: line will be deleted
208 before transmission.
209 -V envid
211 Set the original envelope id. This is propagated across SMTP to
212 servers that support DSNs and is returned in DSN-compliant error
213 messages.
214 -v Go into verbose mode. Alias expansions will be announced, etc.
216 -X logfile
218 Log all traffic in and out of mailers in the indicated log file.
219 This should only be used as a last resort for debugging mailer
220 bugs. It will log a lot of data very quickly.
221 -- Stop processing command flags and use the rest of the arguments
223 as addresses.
224 Options
226 There are also a number of processing options that may be set. Nor‐
227 mally these will only be used by a system administrator. Options may
228 be set either on the command line using the -o flag (for short names),
229 the -O flag (for long names), or in the configuration file. This is a
230 partial list limited to those options that are likely to be useful on
231 the command line and only shows the long names; for a complete list
232 (and details), consult the Sendmail Installation and Operation Guide.
233 The options are:
234 AliasFile=file
236 Use alternate alias file.
237 HoldExpensive
239 On mailers that are considered ``expensive'' to connect to,
240 don't initiate immediate connection. This requires queueing.
241 CheckpointInterval=N
243 Checkpoint the queue file after every N successful deliveries
244 (default 10). This avoids excessive duplicate deliveries when
245 sending to long mailing lists interrupted by system crashes.
246 DeliveryMode=x
248 Set the delivery mode to x. Delivery modes are `i' for interac‐
249 tive (synchronous) delivery, `b' for background (asynchronous)
250 delivery, `q' for queue only - i.e., actual delivery is done the
251 next time the queue is run, and `d' for deferred - the same as
252 `q' except that database lookups for maps which have set the -D
253 option (default for the host map) are avoided.
254 ErrorMode=x
256 Set error processing to mode x. Valid modes are `m' to mail
257 back the error message, `w' to ``write'' back the error message
258 (or mail it back if the sender is not logged in), `p' to print
259 the errors on the terminal (default), `q' to throw away error
260 messages (only exit status is returned), and `e' to do special
261 processing for the BerkNet. If the text of the message is not
262 mailed back by modes `m' or `w' and if the sender is local to
263 this machine, a copy of the message is appended to the file
264 dead.letter in the sender's home directory.
265 SaveFromLine
267 Save UNIX-style From lines at the front of messages.
268 MaxHopCount=N
270 The maximum number of times a message is allowed to ``hop''
271 before we decide it is in a loop.
272 IgnoreDots
274 Do not take dots on a line by themselves as a message termina‐
275 tor.
276 SendMimeErrors
278 Send error messages in MIME format. If not set, the DSN (Deliv‐
279 ery Status Notification) SMTP extension is disabled.
280 ConnectionCacheTimeout=timeout
282 Set connection cache timeout.
283 ConnectionCacheSize=N
285 Set connection cache size.
286 LogLevel=n
288 The log level.
289 MeToo=False
291 Don't send to ``me'' (the sender) if I am in an alias expansion.
292 CheckAliases
294 Validate the right hand side of aliases during a newaliases(1)
295 command.
296 OldStyleHeaders
298 If set, this message may have old style headers. If not set,
299 this message is guaranteed to have new style headers (i.e., com‐
300 mas instead of spaces between addresses). If set, an adaptive
301 algorithm is used that will correctly determine the header for‐
302 mat in most cases.
303 QueueDirectory=queuedir
305 Select the directory in which to queue messages.
306 StatusFile=file
308 Save statistics in the named file.
309 Timeout.queuereturn=time
311 Set the timeout on undelivered messages in the queue to the
312 specified time. After delivery has failed (e.g., because of a
313 host being down) for this amount of time, failed messages will
314 be returned to the sender. The default is five days.
315 UserDatabaseSpec=userdatabase
317 If set, a user database is consulted to get forwarding informa‐
318 tion. You can consider this an adjunct to the aliasing mecha‐
319 nism, except that the database is intended to be distributed;
320 aliases are local to a particular host. This may not be avail‐
321 able if your sendmail does not have the USERDB option compiled
322 in.
323 ForkEachJob
325 Fork each job during queue runs. May be convenient on memory-
326 poor machines.
327 SevenBitInput
329 Strip incoming messages to seven bits.
330 EightBitMode=mode
332 Set the handling of eight bit input to seven bit destinations to
333 mode: m (mimefy) will convert to seven-bit MIME format, p (pass)
334 will pass it as eight bits (but violates protocols), and s
335 (strict) will bounce the message.
336 MinQueueAge=timeout
338 Sets how long a job must ferment in the queue between attempts
339 to send it.
340 DefaultCharSet=charset
342 Sets the default character set used to label 8-bit data that is
343 not otherwise labelled.
344 DialDelay=sleeptime
346 If opening a connection fails, sleep for sleeptime seconds and
347 try again. Useful on dial-on-demand sites.
348 NoRecipientAction=action
350 Set the behaviour when there are no recipient headers (To:, Cc:
351 or Bcc:) in the message to action: none leaves the message
352 unchanged, add-to adds a To: header with the envelope recipi‐
353 ents, add-apparently-to adds an Apparently-To: header with the
354 envelope recipients, add-bcc adds an empty Bcc: header, and add-
355 to-undisclosed adds a header reading `To: undisclosed-recipi‐
356 ents:;'.
357 MaxDaemonChildren=N
359 Sets the maximum number of children that an incoming SMTP daemon
360 will allow to spawn at any time to N.
361 ConnectionRateThrottle=N
363 Sets the maximum number of connections per second to the SMTP
364 port to N.
365 In aliases, the first character of a name may be a vertical bar to
367 cause interpretation of the rest of the name as a command to pipe the
368 mail to. It may be necessary to quote the name to keep sendmail from
369 suppressing the blanks from between arguments. For example, a common
370 alias is:
371 msgs: "|/usr/bin/msgs -s"
373 Aliases may also have the syntax ``:include:filename'' to ask sendmail
375 to read the named file for a list of recipients. For example, an alias
376 such as:
377 poets: ":include:/usr/local/lib/poets.list"
379 would read /usr/local/lib/poets.list for the list of addresses making
381 up the group.
382 Sendmail returns an exit status describing what it did. The codes are
384 defined in <sysexits.h>:
385 EX_OK Successful completion on all addresses.
387 EX_NOUSER
389 User name not recognized.
390 EX_UNAVAILABLE
392 Catchall meaning necessary resources were not available.
393 EX_SYNTAX
395 Syntax error in address.
396 EX_SOFTWARE
398 Internal software error, including bad arguments.
399 EX_OSERR
401 Temporary operating system error, such as ``cannot fork''.
402 EX_NOHOST
404 Host name not recognized.
405 EX_TEMPFAIL
407 Message could not be sent immediately, but was queued.
408 If invoked as newaliases, sendmail will rebuild the alias database. If
410 invoked as mailq, sendmail will print the contents of the mail queue.
411 If invoked as hoststat, sendmail will print the persistent host status
412 database. If invoked as purgestat, sendmail will purge expired entries
413 from the persistent host status database. If invoked as smtpd, send‐
414 mail will act as a daemon, as if the -bd option were specified.
415
417 sendmail often gets blamed for many problems that are actually the
418 result of other problems, such as overly permissive modes on directo‐
419 ries. For this reason, sendmail checks the modes on system directories
420 and files to determine if they can be trusted. Although these checks
421 can be turned off and your system security reduced by setting the Dont‐
422 BlameSendmail option, the permission problems should be fixed. For
423 more information, see:
424 http://www.sendmail.org/tips/DontBlameSendmail.html
426
428 Except for the file /etc/mail/sendmail.cf itself the following path‐
429 names are all specified in /etc/mail/sendmail.cf. Thus, these values
430 are only approximations.
431 /etc/aliases
433 raw data for alias names
434 /etc/mail/aliases.db
436 data base of alias names
437 /etc/mail/sendmail.cf
439 configuration file
440 /etc/mail/helpfile
442 help file
443 /var/log/mail/statistics
445 collected statistics
446 /var/spool/mqueue/*
448 temp files
449
451 mail(1), rmail(1), syslog(3), aliases(5), mailaddr(7),
452 DARPA Internet Request For Comments RFC819, RFC821, RFC822. Sendmail
454 Installation and Operation Guide, No. 8, SMM.
455 http://www.sendmail.org/
457
459 The sendmail command appeared in 4.2BSD.
460 $Date: 2003/12/01 17:02:41 $ SENDMAIL(8)