sendmail - an electronic mail transport agent
sendmail [flags] [address ...] [-v]
hoststat
purgestat
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 [Toc] [Back]
-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 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
the background
listening on socket 25 for incoming SMTP
connections.
By default, Sendmail will also listen on socket
587 for RFC
2476 message submission. 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 RFC 821 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.
The category
is either an integer or a name specifying the
topic; the
level is an integer specifying the level of debugging output
desired. Higher levels generally mean more output. More
than one flag may be specified by separating
flags 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 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.
-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.
-qG name 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.
-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 [Toc] [Back]
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(8) 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.
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
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/sendmail.hf help file
/var/log/sendmail.st collected statistics
/var/spool/mqueue/* temp files
mail(1), syslog(3), aliases(5), mailer.conf(5), mailaddr(7),
mail.local(8), mailq(8), newaliases(8), rc(8), rmail(8)
DARPA Internet Request For Comments RFC 819, RFC 821, RFC
822.
"Sendmail Installation and Operation Guide",
/usr/share/doc/smm/08.sendmailop/.
"Sendmail - An Internetwork Mail Router",
/usr/share/doc/smm/09.sendmail/.
"Filtering Mail with Sendmail",
/usr/share/doc/html/milter/index.html.
http://www.sendmail.org/
The sendmail command appeared in 4.2BSD.
OpenBSD 3.6 December 1, 2003
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