sendmail(1M)
sendmail, smtpd --
an electronic mail transport agent
Synopsis
sendmail flags address ...
smtpd
Description
sendmail sends a message to one or more recipients, routing
the message over whatever networks are necessary. It 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. For example,
if ``john'' sends to ``group'', and ``group'' includes ``john'' in
in the expansion, then the letter will also be delivered to ``john''.
Flags
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
Carriage return-Linefeed (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 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.
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.
F fullname-
Set the full name of the sender.
f name-
Sets the name of the ``from'' person (that is, the envelope
sender of the mail). This address can 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 can 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.
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-
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
success-
to be notified when the message is successfully delivered
n-
Do not do aliasing.
O option=value-
Set option to the specified value. This form uses
long names. See
``Options''
for more details.
o xvalue-
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
UNRESOLVED XREF-0
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]-
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.
qI substr-
Limit processed jobs to those containing substr as a
substring of the queue ID.
qR substr-
Limit processed jobs to those containing substr as a
substring of one of the recipients.
qS substr-
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
hdrs-
to 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. Any addresses
in the argument list will be suppressed, that is, they will not
receive copies even if listed in the message header.
U-
Initial (user) submission. This should always be set when called from
a user agent such as
mail(1)
or exmh and never be set when called by a network delivery
agent such as
rmail(1M).
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, and so on.
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
UNRESOLVED XREF-0.
The options are as follows:
AliasFile=file-
Use alternate alias file.
HoldExpensive-
On mailers that are considered ``expensive'' to connect to, do not
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-
interactive (synchronous) delivery
b-
background (asynchronous) delivery
q-
queue only; that is, actual delivery is done the next time the queue
is run
d-
deferred; the same as q except that database lookups
(notably DNS and NIS lookups) are avoided
ErrorMode=x-
Set error processing to mode x. Valid modes are:
m-
mail back the error message
w-
``write'' back the error message (or mail it back if the sender is
not logged in)
p-
print the errors on the terminal (default)
q-
throw away error messages (only exit status is returned),
e-
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-
Send to ``me'' (the sender) also if I am in an alias expansion.
CheckAliases-
Validate the right hand side of aliases during a
newaliases(1M)
command.
OldStyleHeaders-
If set, this message may have old style headers. If not set, this
message is guaranteed to have new style headers (that is, 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 (for examle, 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)
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
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:
-literal -offset indent -compact
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.
Exit codes
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(1M),
sendmail will rebuild the alias database. If invoked as
mailq(1),
sendmail will print the contents of the mail queue.
If invoked as
hoststat(1M),
sendmail will print the persistent host status database.
If invoked as
purgestat(1M),
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 is sometimes implicated in
problems that are actually the result of such things as
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 web site.
Files
Except for the file /etc/sendmail.cf itself
and the daemon process ID file,
the following
pathnames are all specified in /etc/sendmail.cf.
/etc/mail/aliases-
raw data for alias names
/etc/mail/aliases.db-
data base of alias names
/etc/sendmail.cf-
configuration file
/etc/mail/sendmail.hf-
help file
/etc/mail/sendmail.st-
collected statistics
/var/spool/mqueue/*-
temp files
/etc/sendmail.pid-
The process ID of the daemon
References
aliases(4),
mailaddr(1M),
mailx(1),
rmail(1M),
syslog(3G)
RFC819, RFC821, RFC822
Notices
For a non-networked system, the
sendmail(1M)
startup script
/etc/mail/sendmailrc (which is linked to
/etc/rc2.d/S81sendmail,
/etc/rc1.d/K68sendmail,
and /etc/rc0.d/K68sendmail) automatically
edits the file /etc/service.switch
to contain an entry which directs
sendmail to only look up host names in
/etc/hosts, effectively disabling DNS lookups.
The sendmailrc script
only attempts this auto-configuration if the
/etc/service.switch file exists,
and contains the following comment at the top of the file:
# AUTO=YES
If the /etc/service.switch file does not exist, it is not created;
if this file exists, but does not contain the # AUTO=YES
comment,
the file is not altered.
By default, auto-configuration is enabled.
Therefore, if you want to include your own customizations,
you must change the comment in the service.switch
file to:
# AUTO=NO
See
UNRESOLVED XREF-0
for more information.
If you have added or removed a networking card from your hardware
configuration using the Network Configuration Manager,
you must stop and re-start
sendmail(1M)
in the case where the manager does
not ask you to reboot the system. You may do so by executing the following
commands:
/etc/mail/sendmailrc stop
/etc/mail/sendmailrc start
© 2004 The SCO Group, Inc. All rights reserved.
UnixWare 7 Release 7.1.4 - 25 April 2004