SENDMAIL(8) FreeBSD System Manager's Manual SENDMAIL(8)
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.
-Btype 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 CRLF, and
all messages will be generated with a CRLF at the end. Also, the
``From:'' and ``Sender:'' fields are examined for the name of the
sender.
-bC Check the configuration file.
-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.
-Cfile Use alternate configuration file. Sendmail gives up any enhanced
(set-user-ID or set-group-ID) privileges if an alternate
configuration file is specified.
-D logfile
Send debugging output to the indicated log file instead of stdout.
-dcategory.level...
Set the debugging flag for category to level. Category is either
an integer or a name specifying the topic, and level an integer
specifying the level of debugging output desired. Higher levels
generally mean more output. More than one flag can be specified
by separating them with commas. A list of numeric debugging
categories can be found in the TRACEFLAGS file in the sendmail
source distribution.
The option -d0.1 prints the version of sendmail and the options it
was compiled with.
Most other categories are only useful with, and documented in,
sendmail's source code.
-Ffullname
Set the full name of the sender.
-fname 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 .
-hN 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 Do not strip a leading dot from lines in incoming messages, and do
not treat a dot on a line by itself as the end of an incoming
message. 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.
-ox 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.
-pprotocol
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 -qtime, 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.
-qf Process saved messages in the queue once and do not fork(), but
run in the foreground.
-qGname
Process jobs in queue group called name only.
-q[!]Isubstr
Limit processed jobs to those containing substr as a substring of
the queue id or not when ! is specified.
-q[!]Qsubstr
Limit processed jobs to quarantined jobs containing substr as a
substring of the quarantine reason or not when ! is specified.
-q[!]Rsubstr
Limit processed jobs to those containing substr as a substring of
one of the recipients or not when ! is specified.
-q[!]Ssubstr
Limit processed jobs to those containing substr as a substring of
the sender or not when ! is specified.
-Q[reason]
Quarantine a normal queue items with the given reason or
unquarantine quarantined queue items if no reason is given. This
should only be used with some sort of item matching using as
described above.
-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.
-rname 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.
-U If a mail submission via the command line requires the use of the
SMTPUTF8 argument for the MAIL command, e.g., because a header
uses UTF-8 encoding, but the addresses on the command line are all
ASCII, then this option must be used. Only available if EAI
support is enabled, and the SMTPUTF8 option is set.
-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.
-- 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.
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.
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 the Sendmail Installation and Operation Guide
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/mail/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), syslog(3), aliases(5), mailaddr(7), mail.local(8), rc(8),
rmail(8)
DARPA Internet Request For Comments RFC819, RFC821, RFC822. Sendmail
Installation and Operation Guide, No. 8, SMM.
http://www.sendmail.org/
US Patent Numbers 6865671, 6986037.
HISTORY
The sendmail command appeared in 4.2BSD.
$Date: 2013-11-22 20:51:56 $ SENDMAIL(8)