Sendmail includes a robust (and complex!) configuration file called "sendmail.cf," which is located in the /etc/mail directory. The Sendmail configuration is beyond the scope of this document, and in most cases, customizing this configuration file is unnecessary.
Whenever you make changes to this or the other Sendmail configuration files discussed in the Email Services chapter, you must restart the Sendmail daemon as described in the previous section.
Support Boundary:
When using our provided Sendmail application, technical assistance is given for matters discussed in this user guide on the basics of mail delivery and configuration of the following files:
/etc/mail/aliases
/etc/mail/virtusertable
/etc/mail/catchall
/etc/mail/access
/etc/mail/local-host-names
No technical assistance is provided for customizing the /etc/mail/sendmail.cf file. A customer who has modified this file from its default configuration assumes responsibility for Sendmail related issues.