sendmail(8)

NAME

sendmail − send mail over the Internet

SYNTAX

/usr/lib/sendmail [ options ] [ address ... ]

newaliases

mailq

DESCRIPTION

The sendmail daemon sends a message to one or more people, routing the message over whatever networks are necessary. The sendmail daemon does internetwork forwarding as necessary to deliver the message to the correct place.

The sendmail daemon
is not intended as a user interface routine. Other programs provide user-friendly front ends. The sendmail daemon
is used only to deliver preformatted messages.

With no options, sendmail reads its standard input up to a CTRL/D or a line with a single dot and sends a copy of the letter found there to all of the addresses listed. It determines which network 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. Normally the sender is not included in any alias expansions. For example, if John sends to group, and group includes john in the expansion, then the letter will not be delivered to john. If invoked as newaliases, sendmail will rebuild the alias data base.

For proper locking, the mode of /usr/spool/mail must be 777 with the sticky bit set. The sticky bit prevents one person from removing the mailbox of another.

The mailq command prints the contents of the mail queue.

OPTIONS

−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.

−bi
Initialize the alias data base.

−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. This flag implies all the operations of the ba flag that are compatible with SMTP. 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.

−bz
Create the configuration freeze file.

−Cfile
Use alternate configuration file.

−dX
Set debugging value to X.

−Ffullname
Set the full name of the sender.

−fname
Sets the name of the “from” person (that is, the sender of the mail). The −f option can only be used by the special users root, daemon, and network, or if the person you are trying to become is the same as the person you are.

−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.

−nDo not do aliasing.

−ox
Set option x to the specified value. Options are described below.

−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, “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.

−rname
An alternate and obsolete form of the −f flag.

−tRead message for recipients. To:, Cc:, and Bcc: lines will be scanned for people to send to. The Bcc: line will be deleted before transmission. Any addresses in the argument list will be suppressed.

−vGo into verbose mode. Alias expansions will be announced, and so forth.

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 or in the configuration file. The options are:

Afile
Use alternate alias file.

cOn mailers that are considered “expensive” to connect to, do not initiate immediate connection. This requires queueing.

dxSet the delivery mode to x. Delivery modes are “i” for interactive (synchronous) delivery, “b” for background (asynchronous) delivery, and “q” for queue only; for example, actual delivery is done the next time the queue is run.

DTry to automatically rebuild the alias data base if necessary.

exSet 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.

Fmode
The mode to use when creating temporary files.

fSave UNIX-style From lines at the front of messages.

gNThe default group ID to use when calling mailers.

Hfile
The SMTP help file.

iDo not take dots on a line by themselves as a message terminator.

LnThe log level.

mSend to “me” (the sender) also if I am in an alias expansion.

oIf 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.

Qqueuedir
Select the directory in which to queue messages.

rtimeout
The timeout on reads; if none is set, sendmail will wait forever for a mailer.

Sfile
Save statistics in the named file.

sAlways instantiate the queue file, even under circumstances where it is not strictly necessary.

Ttime
Set the timeout on messages in the queue to the specified time. After sitting in the queue for this amount of time, they will be returned to the sender. The default is three days.

tstz,dtz
Set the name of the time zone.

uNSet the default user ID for mailers.

If the first character of the user name is a vertical bar, the rest of the user name is used as the name of a program to pipe the mail to. It may be necessary to quote the name of the user to keep sendmail from suppressing the blanks from between arguments.

RETURN VALUE

The sendmail daemon returns an exit status describing what it did. The codes are defined in <sysexits.h>

EX_OKSuccessful completion on all addresses.

EX_NOUSERUser name not recognized.

EX_UNAVAILABLENecessary resources were not available.

EX_SYNTAXSyntax error in address.

EX_SOFTWAREInternal software error, including bad arguments.

EX_OSERRTemporary operating system error, such as “cannot fork”.

EX_NOHOSTHost name not recognized.

EX_TEMPFAILMessage could not be sent immediately, but was queued.

Installing Sendmail for Networks

After installing the ULTRIX software, you can install sendmail. For DECnet-ULTRIX, DARPA (Department of Defense Advanced Research Projects Agency), or uucp networks, use the sendmail configuration file, exampleether.cf. This file is in the directory, /usr/src/usr.lib/sendmail/cf. This is the only sendmail prototype configuration file supplied with ULTRIX.

To install sendmail for networks, follow these steps:

1.Execute a makefile that creates all the binary files needed.

2.Copy the appropriate prototype file to a file named for your system. Use the form systemname.cf in the same directory. The systemname is the name for the system that you are installing.

3.Copy the file you created, systemname.cf, to /usr/lib/sendmail.cf.

System Load Configuration

There are two sendmail configuration options that you can adjust for system load configurations. These are the load average at which sendmail queues messages for later delivery (the lowercase x option) and the load average at which sendmail refuses further connections (the uppercase X option). Change the values for these options in the file, /usr/lib/sendmail.cf, depending on the type of system you have and its peak load averages.

The internal default for the load average at which sendmail queues messages for later delivery is 8, as shown in the following example:

0x8

Large systems (8800 class) can set this value to about 20 to 25. The general rule for small systems (MicroVAX) is about 4. The exact setting depends on processor speed, swap space, memory size, and normal load average.

To set the load average for sendmail on your system, check the load average of your system during a normal work period and set the x option a few degrees higher. Too low a value causes mail to be unnecessarily delayed, while too high a value can increase the load on the machine during transient peaks.

The default load average at which sendmail refuses further connections is 12, as shown in this example:

0X12

Large systems can set the X option at approximately 25 to 30, depending on processor speed, swap space, memory size and normal load average. Small systems with limited swap space should set X at about 5 or 6.

Enter changes to the sendmail options in the /usr/lib/sendmail.cf file after the options heading and before the messages precedences heading. After changing sendmail.cf, kill the sendmail daemon, refreeze the configuration file, then restart the sendmail daemon.

RESTRICTIONS

The sendmail command converts blanks in addresses to dots. This is incorrect according to the old ARPANET mail protocol RFC 733 (NIC 41952), but is consistent with the new protocols (RFC 822).

The debug flag, -dX is undefined. Any references to this flag will not produce the output described in the ULTRIX-32 Supplementary Documents.

FILES

Except for /usr/lib/sendmail.cf, these pathnames are all specified in /usr/lib/sendmail.cf. Thus, these values are only approximations.

/usr/lib/aliasesRaw data for alias names
/usr/lib/aliases.pag
/usr/lib/aliases.dirData base of alias names
/usr/lib/sendmail.cfConfiguration file
/usr/lib/sendmail.fcFrozen configuration
/usr/lib/sendmail.hfHelp file
/usr/lib/sendmail.stCollected statistics
/usr/bin/uuxDeliver uucp mail
/usr/net/bin/v6mailDeliver local mail
/usr/net/bin/sendberkmailDeliver Berknet mail
/usr/lib/mailers/arpaDeliver ARPANET mail
/usr/spool/mqueue/*Temp files

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