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