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 Do not strip a leading dot from lines in incoming messages, and
126 do not treat a dot on a line by itself as the end of an incoming
127 message. This should be set if you are reading data from a
128 file.
129 -L tag Set the identifier used in syslog messages to the supplied tag.
131 -N dsn Set delivery status notification conditions to dsn, which can be
133 `never' for no notifications or a comma separated list of the
134 values `failure' to be notified if delivery failed, `delay' to
135 be notified if delivery is delayed, and `success' to be notified
136 when the message is successfully delivered.
137 -n Don't do aliasing.
139 -O option=value
141 Set option option to the specified value. This form uses long
142 names. See below for more details.
143 -ox value
145 Set option x to the specified value. This form uses single
146 character names only. The short names are not described in this
147 manual page; see the Sendmail Installation and Operation Guide
148 for details.
149 -pprotocol
151 Set the name of the protocol used to receive the message. This
152 can be a simple protocol name such as ``UUCP'' or a protocol and
153 hostname, such as ``UUCP:ucbvax''.
154 -q[time]
156 Process saved messages in the queue at given intervals. If time
157 is omitted, process the queue once. Time is given as a tagged
158 number, with `s' being seconds, `m' being minutes (default), `h'
159 being hours, `d' being days, and `w' being weeks. For example,
160 `-q1h30m' or `-q90m' would both set the timeout to one hour
161 thirty minutes. By default, sendmail will run in the back‐
162 ground. This option can be used safely with -bd.
163 -qp[time]
165 Similar to -qtime, except that instead of periodically forking a
166 child to process the queue, sendmail forks a single persistent
167 child for each queue that alternates between processing the
168 queue and sleeping. The sleep time is given as the argument; it
169 defaults to 1 second. The process will always sleep at least 5
170 seconds if the queue was empty in the previous queue run.
171 -qf Process saved messages in the queue once and do not fork(), but
173 run in the foreground.
174 -qGname
176 Process jobs in queue group called name only.
177 -q[!]Isubstr
179 Limit processed jobs to those containing substr as a substring
180 of the queue id or not when ! is specified.
181 -q[!]Qsubstr
183 Limit processed jobs to quarantined jobs containing substr as a
184 substring of the quarantine reason or not when ! is specified.
185 -q[!]Rsubstr
187 Limit processed jobs to those containing substr as a substring
188 of one of the recipients or not when ! is specified.
189 -q[!]Ssubstr
191 Limit processed jobs to those containing substr as a substring
192 of the sender or not when ! is specified.
193 -Q[reason]
195 Quarantine a normal queue items with the given reason or unquar‐
196 antine quarantined queue items if no reason is given. This
197 should only be used with some sort of item matching using as
198 described above.
199 -R return
201 Set the amount of the message to be returned if the message
202 bounces. The return parameter can be `full' to return the
203 entire message or `hdrs' to return only the headers. In the
204 latter case also local bounces return only the headers.
205 -rname An alternate and obsolete form of the -f flag.
207 -t Read message for recipients. To:, Cc:, and Bcc: lines will be
209 scanned for recipient addresses. The Bcc: line will be deleted
210 before transmission.
211 -V envid
213 Set the original envelope id. This is propagated across SMTP to
214 servers that support DSNs and is returned in DSN-compliant error
215 messages.
216 -v Go into verbose mode. Alias expansions will be announced, etc.
218 -X logfile
220 Log all traffic in and out of mailers in the indicated log file.
221 This should only be used as a last resort for debugging mailer
222 bugs. It will log a lot of data very quickly.
223 -- Stop processing command flags and use the rest of the arguments
225 as addresses.
226 Options
228 There are also a number of processing options that may be set. Nor‐
229 mally these will only be used by a system administrator. Options may
230 be set either on the command line using the -o flag (for short names),
231 the -O flag (for long names), or in the configuration file. This is a
232 partial list limited to those options that are likely to be useful on
233 the command line and only shows the long names; for a complete list
234 (and details), consult the Sendmail Installation and Operation Guide.
235 The options are:
236 AliasFile=file
238 Use alternate alias file.
239 HoldExpensive
241 On mailers that are considered ``expensive'' to connect to,
242 don't initiate immediate connection. This requires queueing.
243 CheckpointInterval=N
245 Checkpoint the queue file after every N successful deliveries
246 (default 10). This avoids excessive duplicate deliveries when
247 sending to long mailing lists interrupted by system crashes.
248 DeliveryMode=x
250 Set the delivery mode to x. Delivery modes are `i' for interac‐
251 tive (synchronous) delivery, `b' for background (asynchronous)
252 delivery, `q' for queue only - i.e., actual delivery is done the
253 next time the queue is run, and `d' for deferred - the same as
254 `q' except that database lookups for maps which have set the -D
255 option (default for the host map) are avoided.
256 ErrorMode=x
258 Set error processing to mode x. Valid modes are `m' to mail
259 back the error message, `w' to ``write'' back the error message
260 (or mail it back if the sender is not logged in), `p' to print
261 the errors on the terminal (default), `q' to throw away error
262 messages (only exit status is returned), and `e' to do special
263 processing for the BerkNet. If the text of the message is not
264 mailed back by modes `m' or `w' and if the sender is local to
265 this machine, a copy of the message is appended to the file
266 dead.letter in the sender's home directory.
267 SaveFromLine
269 Save UNIX-style From lines at the front of messages.
270 MaxHopCount=N
272 The maximum number of times a message is allowed to ``hop''
273 before we decide it is in a loop.
274 IgnoreDots
276 Do not take dots on a line by themselves as a message termina‐
277 tor.
278 SendMimeErrors
280 Send error messages in MIME format. If not set, the DSN (Deliv‐
281 ery Status Notification) SMTP extension is disabled.
282 ConnectionCacheTimeout=timeout
284 Set connection cache timeout.
285 ConnectionCacheSize=N
287 Set connection cache size.
288 LogLevel=n
290 The log level.
291 MeToo=False
293 Don't send to ``me'' (the sender) if I am in an alias expansion.
294 CheckAliases
296 Validate the right hand side of aliases during a newaliases(1)
297 command.
298 OldStyleHeaders
300 If set, this message may have old style headers. If not set,
301 this message is guaranteed to have new style headers (i.e., com‐
302 mas instead of spaces between addresses). If set, an adaptive
303 algorithm is used that will correctly determine the header for‐
304 mat in most cases.
305 QueueDirectory=queuedir
307 Select the directory in which to queue messages.
308 StatusFile=file
310 Save statistics in the named file.
311 Timeout.queuereturn=time
313 Set the timeout on undelivered messages in the queue to the
314 specified time. After delivery has failed (e.g., because of a
315 host being down) for this amount of time, failed messages will
316 be returned to the sender. The default is five days.
317 UserDatabaseSpec=userdatabase
319 If set, a user database is consulted to get forwarding informa‐
320 tion. You can consider this an adjunct to the aliasing mecha‐
321 nism, except that the database is intended to be distributed;
322 aliases are local to a particular host. This may not be avail‐
323 able if your sendmail does not have the USERDB option compiled
324 in.
325 ForkEachJob
327 Fork each job during queue runs. May be convenient on memory-
328 poor machines.
329 SevenBitInput
331 Strip incoming messages to seven bits.
332 EightBitMode=mode
334 Set the handling of eight bit input to seven bit destinations to
335 mode: m (mimefy) will convert to seven-bit MIME format, p (pass)
336 will pass it as eight bits (but violates protocols), and s
337 (strict) will bounce the message.
338 MinQueueAge=timeout
340 Sets how long a job must ferment in the queue between attempts
341 to send it.
342 DefaultCharSet=charset
344 Sets the default character set used to label 8-bit data that is
345 not otherwise labelled.
346 DialDelay=sleeptime
348 If opening a connection fails, sleep for sleeptime seconds and
349 try again. Useful on dial-on-demand sites.
350 NoRecipientAction=action
352 Set the behaviour when there are no recipient headers (To:, Cc:
353 or Bcc:) in the message to action: none leaves the message
354 unchanged, add-to adds a To: header with the envelope recipi‐
355 ents, add-apparently-to adds an Apparently-To: header with the
356 envelope recipients, add-bcc adds an empty Bcc: header, and add-
357 to-undisclosed adds a header reading `To: undisclosed-recipi‐
358 ents:;'.
359 MaxDaemonChildren=N
361 Sets the maximum number of children that an incoming SMTP daemon
362 will allow to spawn at any time to N.
363 ConnectionRateThrottle=N
365 Sets the maximum number of connections per second to the SMTP
366 port to N.
367 In aliases, the first character of a name may be a vertical bar to
369 cause interpretation of the rest of the name as a command to pipe the
370 mail to. It may be necessary to quote the name to keep sendmail from
371 suppressing the blanks from between arguments. For example, a common
372 alias is:
373 msgs: "|/usr/bin/msgs -s"
375 Aliases may also have the syntax ``:include:filename'' to ask sendmail
377 to read the named file for a list of recipients. For example, an alias
378 such as:
379 poets: ":include:/usr/local/lib/poets.list"
381 would read /usr/local/lib/poets.list for the list of addresses making
383 up the group.
384 Sendmail returns an exit status describing what it did. The codes are
386 defined in <sysexits.h>:
387 EX_OK Successful completion on all addresses.
389 EX_NOUSER
391 User name not recognized.
392 EX_UNAVAILABLE
394 Catchall meaning necessary resources were not available.
395 EX_SYNTAX
397 Syntax error in address.
398 EX_SOFTWARE
400 Internal software error, including bad arguments.
401 EX_OSERR
403 Temporary operating system error, such as ``cannot fork''.
404 EX_NOHOST
406 Host name not recognized.
407 EX_TEMPFAIL
409 Message could not be sent immediately, but was queued.
410 If invoked as newaliases, sendmail will rebuild the alias database. If
412 invoked as mailq, sendmail will print the contents of the mail queue.
413 If invoked as hoststat, sendmail will print the persistent host status
414 database. If invoked as purgestat, sendmail will purge expired entries
415 from the persistent host status database. If invoked as smtpd, send‐
416 mail will act as a daemon, as if the -bd option were specified.
417
419 sendmail often gets blamed for many problems that are actually the
420 result of other problems, such as overly permissive modes on directo‐
421 ries. For this reason, sendmail checks the modes on system directories
422 and files to determine if they can be trusted. Although these checks
423 can be turned off and your system security reduced by setting the Dont‐
424 BlameSendmail option, the permission problems should be fixed. For
425 more information, see:
426 http://www.sendmail.org/tips/DontBlameSendmail.html
428
430 Except for the file /etc/mail/sendmail.cf itself the following path‐
431 names are all specified in /etc/mail/sendmail.cf. Thus, these values
432 are only approximations.
433 /etc/aliases
435 raw data for alias names
436 /etc/aliases.db
438 data base of alias names
439 /etc/mail/sendmail.cf
441 configuration file
442 /etc/mail/helpfile
444 help file
445 /var/log/mail/statistics
447 collected statistics
448 /var/spool/mqueue/*
450 temp files
451
453 mail(1), rmail(1), syslog(3), aliases(5), mailaddr(7),
454 DARPA Internet Request For Comments RFC819, RFC821, RFC822. Sendmail
456 Installation and Operation Guide, No. 8, SMM.
457 http://www.sendmail.org/
459 US Patent Numbers 6865671, 6986037.
461
463 The sendmail command appeared in 4.2BSD.
464 $Date: 2011/03/07 23:44:48 $ SENDMAIL(8)