If you want to relay your Sendmail at your ISP mail relay server which need SMTP authentication, you may follow the steps below: -
1. Find the DS in /etc/mail/sendmail.cf and change it as below: -
DSmail.example.com
2. Put the following line in /etc/mail/access file in one line: -
AuthInfo:mail.example.com "U:user@example.com" "I:user@example.com" "P:password" "R:example.com" "M:LOGIN PLAIN"
3. Then, restart your Sendmail service as below: -
service sendmail restart
4. Finally, you can monitor your maillog using the command below: -
tail -f /var/log/maillog
Note: The above was tested on Sendmail 8.13.5-3 in Fedora Core 5













