sendmail Performance Tuning

6.1. Configuration

This section explicitly focuses on the options available within the sendmail.cf file to see how modification of various parameters can improve throughput in different situations. I’ve waited until this point to discuss these issues because tuning the system’s file I/O is almost always more effective in speeding email server throughput, but some configuration options can result in significant changes.

6.1.1. Timeouts

One set of configuration parameters that can lead to performance speedups involves changes to sendmail’s timeouts, although altering some parameters in this area can prove perilous. RFC 2821 specifies some minimum timeouts for MTAs at different phases of an SMTP protocol exchange. While sendmail will allow timeout ...