Software Development:
Individual Programming

Symptom

The mail server cannot be reached from your local computer or mails can be transmitted to the mail server but are not forwarded to their final recipients.

Cause

Maybe the Sendmail Mail Transport Agent or the authentication service of the mail server have failed.

Solution

Check in the process list of your server, whether the Sendmail Daemon exists. Log in to your Linux console by SSH and switch to superuser mode. Enter: ps –aux, then press Enter. The server will display a list of all running processes. The process list must contain two entries that look similar to this:

root 31843 0.0 0.1 7668 2468 ? Ss 09:56 0:02 sendmail: accepting connections
smmsp 31852 0.0 0.1 6628 1616 ? Ss 09:56 0:00 sendmail: Queue runner@01:00:00 for ...

If one or both of these entries is missing, Sendmail is not ready.

Alternatively you can restart Sendmail. This is a recommended procedure, because even while Sendmail processes are running, the authentication service „saslauthd“ could have failed. In that case logins are impossible and mails may not be forwarded. Restarting Sendmail will most likely solve all issues that exist during an offline state.

To restart Sendmail, enter: restart_sendmail and press Enter. The server will display a result similar to this:

FreeBSD:
sendmail mta stopped
sendmail submission daemon stopped
SMTP authentication daemon stopped
sendmail mta started
sendmail submission daemon started
SMTP authentication daemon started

Linux:
Shutting down sm-client: [ OK ]
Shutting down sendmail: [ OK ]
Starting sendmail: [ OK ]
Starting sm-client: [ OK ]
Stopping saslauthd: [ OK ]
Starting saslauthd: [ OK ]

When the „Shutting down“, respectively „Stopping“ lines show a [Failed], you know that Sendmail was not ready. After a restart however, the „Starting“ lines must show an [OK].

Overview of frequently asked questions