/etc/sendmail.mc to rebuild /etc/sendmail.cf from
that file, i.e., m4 /etc/mail/sendmail.mc >
/etc/mail/sendmail.cf. E.g., see
Configuring Sendmail to
Use a Smart Host, but that is no longer needed with CentOS 7 and,
though I went from CentOS 5 to 7, may have gone away as a needed step
in CentOS 6. Now, if you modify /etc/sendmail.mc, when
you restart sendmail, e.g., with service sendmail restart,
the sendmail.cf file is automatically rebuilt.
If you issue the command service sendmail restart, you will
see Redirecting to /bin/systemctl restart sendmail.service.
# service sendmail restart Redirecting to /bin/systemctl restart sendmail.service #
If you examine /usr/lib/systemd/system/sendmail.service, you
will see that the
make command, i.e.,
/etc/mail/make, is run.
# locate sendmail.service /etc/systemd/system/multi-user.target.wants/sendmail.service /usr/lib/systemd/system/sendmail.service # cat /usr/lib/systemd/system/sendmail.service [Unit] Description=Sendmail Mail Transport Agent After=syslog.target network.target Conflicts=postfix.service exim.service Wants=sm-client.service [Service] Type=forking PIDFile=/run/sendmail.pid Environment=SENDMAIL_OPTS=-q1h EnvironmentFile=-/etc/sysconfig/sendmail ExecStartPre=-/etc/mail/make ExecStartPre=-/etc/mail/make aliases ExecStart=/usr/sbin/sendmail -bd $SENDMAIL_OPTS $SENDMAIL_OPTARG [Install] WantedBy=multi-user.target Also=sm-client.service #
You can also verify that sendmail.cf is recreated when you
restart Sendmail by modifying sendmail.mc and then restarting
Sendmail as shown below:
# ls -l /etc/mail/sendmail.?? -rw-r--r--. 1 root root 61060 Sep 2 19:44 /etc/mail/sendmail.cf -rw-r--r--. 1 root root 8226 Sep 2 20:03 /etc/mail/sendmail.mc [root@moonpoint bin]# service sendmail restart Redirecting to /bin/systemctl restart sendmail.service [root@moonpoint bin]# ls -l /etc/mail/sendmail.?? -rw-r--r--. 1 root root 60494 Sep 2 20:03 /etc/mail/sendmail.cf -rw-r--r--. 1 root root 8226 Sep 2 20:03 /etc/mail/sendmail.mc #