View Source: sendmail(8) - Waikato Linux Users Group

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!!NAME
sendmail - an electronic mail transport agent

!!SYNOPSIS
__sendmail__ [[ ''flags'' ] [[ ''address ...'' ]
__newaliases__
__mailq__ [[ __-v__ ]
__hoststat__
__purgestat__
__smtpd__

!!DESCRIPTION
__Sendmail__ sends a message to one or more ''recipients,'' routing the message over whatever networks  are necessary. __Sendmail__ does internetwork forwarding as necessary  to deliver the message to the correct place.

__Sendmail__ is not intended as a user interface routine;  other programs provide user-friendly  front ends; __sendmail__ is used only to deliver pre-formatted messages.

With no flags, __sendmail__ reads its standard input  up to an end-of-file  or a line consisting only of a single dot  and sends a copy of the message found there to all of the addresses listed.   It determines the network(s) to use  based on the syntax and contents of the addresses.

Local addresses are looked up in a file  and aliased appropriately. Aliasing can be prevented by preceding the address  with a backslash. Beginning with 8.10, the sender is included in any alias  expansions, e.g.,  if `john' sends to `group',  and `group' includes `john' in the expansion,  then the letter will also be delivered to `john'.

!Parameters

;__-Ac__ : Use submit.cf even if the operation mode does not indicate an initial mail submission.
;__-Am__ : Use sendmail.cf even if the operation mode indicates an initial mail submission.
;__-B__ ''type'' : Set the body type to ''type'' . Current legal values are  7BIT  or   8BITMIME.
;__-ba__ : Go into  ARPANET  mode.  All input lines must end with a CR-LF,  and all messages will be generated with a CR-LF at the end.   Also,  the "From:" and "Sender:"  fields are examined for the name of the sender.
;__-bd__ : Run as a daemon. __Sendmail__ will fork and run in background  listening on socket 25 for incoming SMTP  connections.   This is normally run from  /etc/rc.
;__-bD__ : Same as __-bd__ except runs in foreground.
;__-bh__ : Print the persistent host status database.
;__-bH__ : Purge expired entries from the persistent host status database.
;__-bi__ : Initialize the alias database.
;__-bm__ : Deliver mail in the usual way (default).
;__-bp__ : Print a listing of the queue(s).
;__-bP__ : Print number of entries in the queue(s); only available with shared memory support.
;__-bs__ : Use the  SMTP  protocol as described in  RFC821  on standard input and output.   This flag implies all the operations of the __-ba__ flag that are compatible with  SMTP.
;__-bt__ : Run in address test mode.   This mode reads addresses and shows the steps in parsing;  it is used for debugging configuration tables.
;__-bv__ : Verify names only - do not try to collect or deliver a message. Verify mode is normally used for validating  users or mailing lists.
;__-C__ ''file'' : Use alternate configuration file. __Sendmail__ refuses to run as root if an alternate configuration file is specified.
;__-d__ ''X'' : Set debugging value to ''X'' . 1i
;__-F__ ''fullname'' : Set the full name of the sender.
;__-f__ ''name'' : Sets the name of the "from" person  (i.e., the envelope sender of the mail). This address may also be used in the From: header if that header is missing during initial submission. The envelope sender address is used as the recipient for delivery status notifications and may also appear in a Return-Path: header. __-f__ should only be used  by "trusted" users  (normally ''root'' ,  ''daemon'' , and ''network'' ) or if the person you are trying to become  is the same as the person you are. Otherwise, an X-Authentication-Warning header will be added to the message.
;__-G__ : Relay (gateway) submission of a message, e.g., when __rmail__ calls __sendmail .__
;__-h__ ''N'' : Set the hop count to ''N'' . The hop count is incremented every time the mail is  processed. When it reaches a limit,  the mail is returned with an error message, the victim of an aliasing loop.   If not specified,  ``Received:" lines in the message are counted.
;__-i__ : Ignore dots alone on lines by themselves in incoming messages. This should be set if you are reading data from a file.
;__-L __ ''tag'' : Set the identifier used in syslog messages to the supplied ''tag'' .
;__-N __ ''dsn'' : Set delivery status notification conditions to ''dsn'' , which can be  `never'  for no notifications  or a comma separated list of the values  `failure'  to be notified if delivery failed,  `delay' to be notified if delivery is delayed, and  `success'  to be notified when the message is successfully delivered.
;__-n__ : Don't do aliasing.
;__-O__ ''option''=''value''  : Set option ''option'' to the specified ''value'' . This form uses long names.  See below for more details.
;__-o__ ''x value'' : Set option ''x'' to the specified ''value'' . This form uses single character names only.   The short names are not described in this manual page;  see the ''Sendmail Installation and Operation Guide'' for details.
;__-p__ ''protocol'' : Set the name of the protocol used to receive the message.   This can be a simple protocol name such as "UUCP"  or a protocol and hostname, such as "UUCP:ucbvax".
;__-q__[[''time'']  : Process saved messages in the queue at given intervals.   If ''time'' is omitted, process the queue once. ''Time'' is given as a tagged number,  with  `s'  being seconds,  `m'  being minutes (default),  `h'  being hours,  `d'  being days,  and  `w'  being weeks. For example,  `-q1h30m'  or  `-q90m'  would both set the timeout to one hour thirty minutes. By default, __sendmail__ will run in the background. This option can be used safely with __-bd__ .
;__-qp__[[''time'']  : Similar to __-q''time''__, except that instead of periodically forking a child to process the queue, sendmail forks a single persistent child for each queue that alternates between processing the queue and sleeping. The sleep time is given as the argument; it defaults to 1 second. The process will always sleep at least 5 seconds if the queue was empty in the previous queue run.
;__-q__f : Process saved messages in the queue once and do not fork(), but run in the foreground.
;__-q__G name : Process jobs in queue group called ''name'' only.
;__-q__[[''!'']I substr : Limit processed jobs to those containing ''substr'' as a substring of the queue id or not when ''!'' is specified.
;__-q__[[''!'']R substr : Limit processed jobs to those containing ''substr'' as a substring of one of the recipients or not when ''!'' is specified.
;__-q__[[''!'']S substr : Limit processed jobs to those containing ''substr'' as a substring of the sender or not when ''!'' is specified.
;__-R __ ''return'' : Set the amount of the message to be returned  if the message bounces. The ''return'' parameter can be  `full'  to return the entire message or  `hdrs'  to return only the headers.   In the latter case also local bounces return only the headers.
;__-r__ ''name'' : An alternate and obsolete form of the __-f__ flag.
;__-t__ : Read message for recipients.   To:, Cc:, and Bcc: lines will be scanned for recipient addresses.   The Bcc: line will be deleted before transmission.
;__-V __ ''envid'' : Set the original envelope id.   This is propagated across SMTP to servers that support DSNs  and is returned in DSN-compliant error messages.
;__-v__ : Go into verbose mode.   Alias expansions will be announced, etc.
;__-X __ ''logfile'' : Log all traffic in and out of mailers in the indicated log file. This should only be used as a last resort  for debugging mailer bugs.   It will log a lot of data very quickly.
;__-Â __ : Stop processing command flags and use the rest of the arguments as addresses.

!Options
There are also a number of processing options that may be set. Normally these will only be used by a system administrator.   Options may be set either on the command line  using the __-o__ flag (for short names), the __-O__ flag (for long names),  or in the configuration file.   This is a partial list limited to those options that are likely to be useful on the command line  and only shows the long names;  for a complete list (and details), consult the ''Sendmail Installation and Operation Guide'' . The options are:
;!AliasFile= ''file'' : Use alternate alias file.
;!HoldExpensive  : On mailers that are considered "expensive" to connect to,  don't initiate immediate connection.   This requires queueing.
;!CheckpointInterval= ''N'' : Checkpoint the queue file after every ''N'' successful deliveries (default 10).   This avoids excessive duplicate deliveries  when sending to long mailing lists  interrupted by system crashes. 1i
;!DeliveryMode= ''x'' : Set the delivery mode to ''x'' . Delivery modes are  `i'  for interactive (synchronous) delivery,  `b' for background (asynchronous) delivery,  `q'  for queue only - i.e., actual delivery is done the next time the queue is run, and  `d' for deferred - the same as  `q'  except that database lookups for maps which have set the -D option (default for the host map) are avoided.
;!ErrorMode= ''x'' : Set error processing to mode ''x'' . Valid modes are  `m'  to mail back the error message,  `w'  to "write" back the error message  (or mail it back if the sender is not logged in),  `p'  to print the errors on the terminal  (default),  `q'  to throw away error messages  (only exit status is returned),  and  `e' to do special processing for the !BerkNet.   If the text of the message is not mailed back  by  modes `m' or `w' and if the sender is local to this machine,  a copy of the message is appended to the file ''dead.letter'' in the sender's home directory.
;!SaveFromLine : Save UNIX-style From lines at the front of messages.
;!MaxHopCount= ''N'' : The maximum number of times a message is allowed to "hop"  before we decide it is in a loop.
;!IgnoreDots : Do not take dots on a line by themselves  as a message terminator.
;!SendMimeErrors : Send error messages in MIME format.   If not set, the DSN (Delivery Status Notification) SMTP extension  is disabled.
;!ConnectionCacheTimeout= ''timeout'' : Set connection cache timeout.
;!ConnectionCacheSize= ''N'' : Set connection cache size.
;!LogLevel= ''n'' : The log level.
;!MeToo= ''False'' : Don't send to "me" (the sender) if I am in an alias expansion.
;!CheckAliases : Validate the right hand side of aliases during a newaliases(1) command.
;!OldStyleHeaders : If set, this message may have  old style headers.   If not set,  this message is guaranteed to have new style headers  (i.e., commas instead of spaces between addresses).   If set, an adaptive algorithm is used that will correctly  determine the header format in most cases.
;!QueueDirectory= ''queuedir'' : Select the directory in which to queue messages.
;!StatusFile= ''file'' : Save statistics in the named file.
;Timeout.queuereturn= ''time'' : Set the timeout on undelivered messages in the queue to the specified time.   After delivery has failed  (e.g., because of a host being down)  for this amount of time,  failed messages will be returned to the sender.   The default is five days.
;!UserDatabaseSpec= ''userdatabase'' : If set, a user database is consulted to get forwarding information. You can consider this an adjunct to the aliasing mechanism,  except that the database is intended to be distributed;  aliases are local to a particular host.   This may not be available if your sendmail does not have the USERDB option compiled in.
;!ForkEachJob : Fork each job during queue runs.   May be convenient on memory-poor machines.
;!SevenBitInput : Strip incoming messages to seven bits.
;!EightBitMode= ''mode'' : Set the handling of eight bit input to seven bit destinations to ''mode'' : m (mimefy) will convert to seven-bit MIME format, p (pass) will pass it as eight bits (but violates protocols),  and s (strict) will bounce the message.
;!MinQueueAge= ''timeout'' : Sets how long a job must ferment in the queue between attempts to send it.
;!DefaultCharSet= ''charset'' : Sets the default character set used to label 8-bit data  that is not otherwise labelled.
;!DialDelay= ''sleeptime'' : If opening a connection fails,  sleep for ''sleeptime'' seconds and try again.   Useful on dial-on-demand sites.
;!NoRecipientAction= ''action'' : Set the behaviour when there are no recipient headers (To:, Cc: or Bcc:) in the message to ''action'' : none leaves the message unchanged, add-to adds a To: header with the envelope recipients, add-apparently-to adds an Apparently-To: header with the envelope recipients, add-bcc adds an empty Bcc: header, and add-to-undisclosed adds a header reading `To: undisclosed-recipients:;'.
;!MaxDaemonChildren= ''N'' : Sets the maximum number of children that an incoming SMTP daemon will allow to spawn at any time to ''N'' .
;!ConnectionRateThrottle= ''N'' : Sets the maximum number of connections per second to the SMTP port to ''N'' .

In aliases,  the first character of a name may be  a vertical bar to cause interpretation of  the rest of the name as a command  to pipe the mail to.   It may be necessary to quote the name  to keep __sendmail__ from suppressing the blanks from between arguments.  For example, a common alias is:
;: msgs: "|/usr/bin/msgs -s"

Aliases may also have the syntax :include: filename  to ask __sendmail__ to read the named file for a list of recipients.   For example, an alias such as:
;: poets: ":include:/usr/local/lib/poets.list"

would read ''/usr/local/lib/poets.list'' for the list of addresses making up the group.

__Sendmail__ returns an exit status  describing what it did.   The codes are defined in < ''sysexits.h'' >:
;EX_OK : Successful completion on all addresses.
;EX_NOUSER : User name not recognized.
;EX_UNAVAILABLE : Catchall meaning necessary resources  were not available.
;EX_SYNTAX : Syntax error in address.
;EX_SOFTWARE : Internal software error,  including bad arguments.
;EX_OSERR : Temporary operating system error,  such as ``cannot fork".
;EX_NOHOST : Host name not recognized.
;EX_TEMPFAIL : Message could not be sent immediately,  but was queued.

If invoked as __newaliases__ , __sendmail__ will rebuild the alias database.  If invoked as __mailq__ , __sendmail__ will print the contents of the mail queue. If invoked as __hoststat__ , __sendmail__ will print the persistent host status database. If invoked as __purgestat__ , __sendmail__ will purge expired entries from the persistent host status database. If invoked as __smtpd__ , __sendmail__ will act as a daemon, as if the __-bd__ option were specified.

!!NOTES
__sendmail__ often gets blamed for many problems that are actually the result of other problems, such as overly permissive modes on directories. For this reason, __sendmail__ checks the modes on system directories and files to determine if they can be trusted. Although these checks can be turned off and your system security reduced by setting the __!DontBlameSendmail__ option, the permission problems should be fixed. For more information, see: ''http://www.sendmail.org/tips/!DontBlameSendmail.html''

!!FILES
Except for the file ''/etc/mail/sendmail.cf'' itself the following pathnames are all specified in ''/etc/mail/sendmail.cf'' . Thus,  these values are only approximations.

; /etc/aliases : raw data for alias names
; /etc/mail/aliases.db : data base of alias names
; /etc/mail/sendmail.cf : configuration file
; /etc/mail/helpfile : help file
; /etc/mail/statistics : collected statistics
; /var/spool/mqueue/* : temp files

!!SEE ALSO
mail(1), rmail(1), syslog(3), aliases(5), mailaddr(7),

DARPA  Internet Request For Comments ''RFC819'' , ''RFC821'' , ''RFC822'' . ''Sendmail Installation and Operation Guide'' , No. 8, SMM.

http://www.sendmail.org/

!!HISTORY
The __sendmail__ command appeared in 4.2BSD.
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Last edited on Monday, November 24, 2003 6:17:52 pm by CraigBox
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