A configuration file controls the way that sendmail performs its functions. The configuration file determines the choice of delivery agents, address rewriting rules, and the format of the mail header. The sendmail program uses the information from the /etc/mail/sendmail.cf file to perform its functions.
The Solaris operating system provides two default configuration files in the /etc/mail directory.
submit.cf, a configuration file that is used to run sendmail in mail-submission program mode, instead of daemon mode. For more information, refer to submit.cf Configuration File From Version 8.12 of sendmail.
To set up a mail host or mail gateway, you need to set the relay mailer and relay host parameters that are needed for your mail configuration. For task information, refer to Setting Up Mail Services (Task Map) or Changing the sendmail Configuration in Chapter 13, Mail Services (Tasks). Note that with sendmail version 8.13, you no longer need the main.cf file.
The following list describes some configuration parameters that you can change, depending on the requirements of your site.
Time values, which specify the following information.
Length of time a message remains undelivered in the queue before the message is returned to the sender. Refer to Additional Queue Features From Version 8.12 of sendmail. For a task map, refer to Administering the Queue Directories (Task Map).
Delivery modes, which specify how quickly mail is delivered.
Load limits, which increase efficiency during busy periods. These parameters prevent sendmail from attempting to deliver large messages, messages to many recipients, and messages to sites that have been down for a long time.