On firewalls, for reasons of additional security, it is often
desirable to run sendmail as a user other than
root. Beginning with V8.8
sendmail, you can accomplish this by using the
O RunAsUser=user: group ← configuration file (V8.8 and later) -ORunAsUser=user: group ← command line (V8.8 and later) define(`confRUN_AS_USER', `user: group')← mc configuration (V8.8 and later)
user is either the
uid number of the identity you want
sendmail to run under, or a symbolic name for
that identity. If a symbolic name is specified and if that name
cannot be looked up in the passwd(5) file,
sendmail prints the following error:
readcf: option RunAsUser: unknown user bad symbolic name here
If the symbolic name is found in the passwd(5) file, the uid and gid that sendmail will run under are set from that file.
:, if it is present, signals to
sendmail that you also intend to specify a group
group is either the numeric
gid that you want sendmail
to run as, or a symbolic name for a group. If it is a symbolic name,
that name is looked up in the group(5) file. If
it is not found in that file, the following error is printed:
readcf: option RunAsUser: unknown group bad group name here
If the symbolic name is in that file, sendmail will run under the gid found there.
The sendmail program assumes the identity specified just after the configuration file is read for all but the daemon mode. As a daemon, sendmail remains root to listen for incoming ...