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
-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. This requires Berkeley
IPC.
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.
-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
refuses to run as root if an alternate configuration file is specified.
-dX
Set debugging value to
X.
-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.
-Ooption=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]
Processed 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,
`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.
If
time
is specified,
sendmail
will run in the background.
This option can be used safely with
-bd.
-qIsubstr
Limit processed jobs to those containing
substr
as a substring of the queue id.
-qRsubstr
Limit processed jobs to those containing
substr
as a substring of one of the recipients.
-qSsubstr
Limit processed jobs to those containing
substr
as a substring of the sender.
-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
Initial (user) submission. This should
always
be set when called from a user agent such as
Mail
or
exmh
and
never
be set when called by a network delivery agent such as
rmail.
-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.
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:
