sendmail Performance Tuning

2.3. Creating a .cf file

When the sendmail program starts, it reads a configuration file called send-mail.cf, which is usually stored in the /etc/mail directory. The sendmail.cf file is a strange beast filled with arcane rules and bizarre variables. Following the flow of the sendmail rulesets can prove difficult even for someone who really understands them. For someone without deep sendmail experience, this file can seem daunting, to say the least.

In the “old days,” before sendmail version 8, sendmail.cf files had to be written and maintained by hand. Typically, the sysadmin found one that worked for a given configuration or at another site and modified it to suit another purpose. Tweaking a sendmail.cf file was generally considered to require ...