Sending
a great deal of email really fast is a very complex configuration
problem. In addition to the topics covered in this chapter, learn
everything you can about building the sendmail
binary (Chapter 3), all the
sendmail options (Chapter 24),
and all the available mc configuration features
(Section 4.8 in Chapter 4). It is
only through a full understanding and judicious use of these that you
can maximize delivery speed.
Never use the techniques in this chapter to send unsolicited (spam)
email even accidently. When testing a new setup, it is very easy to
forget that you are connected to the real Internet. Avoid, for
example, the temptation to maintain two configuration files, one with
the ConnectOnlyTo option defined to send test
email to a blackhole machine, and another with that option undefined,
to send real email to the Internet. With such a setup, it is easy to
accidentally send test email to the Internet using the wrong
configuration file.
When using V8.12 and above sendmail, avoid
moving queue files around yourself. The qf file,
for example, internally stores the full pathname of the
df file's directory, so you need
to edit that line as part of a move. Also,
sendmail can split messages at message
submission time into multiple qf files, possibly
in different queues, all sharing a df file with
hard or symbolic links to it. This complexity makes queue file moves
a complex undertaking.
