How to disable sendmail listening on port 25

Posted May 21, 2014

I only use my LAMP based setup to send outbound mail and have another mail server to handle inbound mail.

I wanted to understand (for security reasons) how I could disable sendmail listening on port 25.

I’m running the LAMP image: Ubuntu Sendmail 8.14

jason.chancellor

Submit an answer

You can type!ref in this text area to quickly search our full set of tutorials, documentation & marketplace offerings and insert the link!

These answers are provided by our Community. If you find them useful, show some love by clicking the heart. If you run into issues leave a comment, or add your own answer to help others.

jason.chancellor • May 21, 2014

This is exactly what I needed. Thank you!

Andrew SB • May 21, 2014

Hey Jason, You could setup default firewall rules that allow outgoing connections, but not incoming ones. Assuming you need ports 22 and 80 open, it’s as simple as: <pre> ufw default deny incoming ufw default allow outgoing ufw allow ssh ufw allow http ufw enable </pre> Check out this article for more info on using ufw to setup firewall rules: https://www.digitalocean.com/community/articles/how-to-setup-a-firewall-with-ufw-on-an-ubuntu-and-debian-cloud-server