18.3. Overview of Configuration Files

Traditionally, sendmail was set up through a system configuration file (typically called /etc/mail/sendmail.cf, or in older distributions, /etc/sendmail.cf, or even /usr/lib/sendmail.cf ) that is not anything close to any language you've seen before. Editing the sendmail.cf file to provide customized behavior can be a humbling experience.

Today sendmail makes all configuration options macro driven with an easy-to-understand syntax. The macro method generates configurations to cover most installations, but you always have the option of tuning the resultant sendmail.cf manually to work in a more complex environment.