The following three databases are disk files used to load sendmail.cf
class variables:
- trusted-users file
- The default path of this file is /etc/mail/trusted-users. It
adds usernames, to the list of users that are trusted to send mail
under another user's name, to the class variable t in the configuration
file. By default, the class variable t contains the names daemon,
root, and uucp.
- relay-domains file
- Sendmail copies data written in this file to the class variable
R. This enables relaying in the domains of the /etc/mail/relay-domains
file.
- local-host-names file
- This file is used when systems use the sendmail server as a
mailbox server to hold their mail. By using class variable w in the
configuration file, the mail to the system listed in /etc/mail/local-host-names
will be accepted as a local delivery.