Arguments to sendmail

Arguments to sendmail are listed and described in detail in "Command-Line Arguments to sendmail". Some of the important arguments are described in this section.

Queue Interval

The q flag defines how often sendmail runs the queue. If you run in mode i or b (the default), this time can be relatively long, because it is only relevant when a host that was down restarts. If, however, you run in q mode, the time should be relatively short, as the flag defines the maximum amount of time that a message may sit in the queue. Typical queue time is set to between 15 minutes (q15m) and 1 hour (q1h).

Daemon Mode

If you allow incoming mail over a TCP connection, you should have a daemon running. Set the bd flag in your /etc/rc3.d/S88sendmail file.

You can combine the bd flag and the q flag in one call:

# /usr/lib/sendmail -bd -q30m

Debugging

sendmail has many debug flags, which you set using the d option. Each debug flag has a number and a level, where higher levels mean "print more information." The convention is that you do not need to set levels greater than 9 unless you are debugging that particular piece of code. Table 3-1 shows some examples of debugging flags.

If you have source code, you can refer to the list of debug flags in the code.

Trying a Different Configuration File

You can specify an alternative configuration file by using the C flag; for example, the command

# /usr/lib/sendmail -Ctest.cf

uses the configuration file test.cf instead of the default /etc/mail/sendmail.cf. If you do not define a value for the C flag, it uses the sendmail.cf file in the current directory.