sendmail, 4th Edition

FEATURE(use_ct_file)

Use /etc/mail/trusted-users for a list of trusted users V8.7 and later

V6 sendmail removed the concept of trusted users (Security Features on page 173). V8.7 reintroduced trusted users, but in a form different from that used by V5 sendmail. Now, trusted users are those who can rebuild the aliases database, and who can run sendmail with the -f switch (-f on page 241) without generating an authentication warning (X-Authentication-Warning: on page 1167):

X-Authentication-Warning: host:  user  set sender to other using -f

To prevent this warning, the user should be added to a list of trusted users. Simply use this FEATURE(use_ct_file) and add user to the file /etc/mail/trusted-users (V8.10 and later) or /etc/mail/sendmail.ct (V8.9 and earlier). You declare FEATURE(use_ct_file) like this:

FEATURE(`use_ct_file')

If you want to locate the /etc/mail/trusted-users in a different place or give it a different name, you can do so with this declaration:

define(`confCT_FILE', `/etc/mail/trusted.list')

Note that the file must exist before sendmail is started, or it will complain:

fileclass: cannot open /etc/mail/trusted.list: No such file or directory

If you want the file to optionally exist, you can add a -o (The F Class Command on page 857) to the conf-CT_FILE definition:

define(`confCT_FILE', `-o /etc/mail/trusted_users')

Here, we retain the file’s default name and location, but add the -o to make the file’s presence optional.

You can also add trusted users directly in your mc configuration ...