Prior to installing Messaging Server, you should disable the sendmail daemon if it is running. The Dispatcher, under which the Messaging Server SMTP server runs, needs to bind to port 25. If the sendmail daemon is running (on port 25), the Dispatcher will not be able to bind to port 25.
Change to the /etc/init.d directory.
Stop the sendmail daemon if it is running.
Modify /etc/default/sendmail by adding MODE="".
If the sendmail file does not exist, create the file and then add MODE="".
If a user accidentally runs sendmail start, or if a patch restarts sendmail, then adding this modification prevents sendmail from starting up in daemon mode.
In some cases (especially on Solaris 10), even after you run the /etc/init.d/sendmail stop command, sendmail is autorestarted. In this case, use the following command to stop the sendmail process:
svcadmin disable network/smtp:sendmail