How to open a port with CSF in WHM

Warning: Way to the Web Ltd. (the company behind ConfigServer) announced it has closed permanently as of August 31, 2025; however, their free scripts will remain available under the GPLv3 license. 
cPanel now provides a fork of CSF:

cPanel will provide its own fork of CSF starting Feb 25th, 2026

Question

How do you open a port with CSF in WHM?

Answer

1. Log in to WHM as root
2. Navigate to Home / Plugins / ConfigServer Security & Firewall.
3. In the csf -ConfigServer Firewall section, click the Firewall Configuration button.
4. Scroll down to Allow incoming TCP ports.
5. Enter the incoming TCP port to open in the TCP_IN textbox.
6. Scroll down to Allow outgoing TCP ports.
7. Enter the outgoing TCP port to open in the TCP_OUT textbox.
8. Scroll down to Allow incoming UDP ports.
9. Enter the incoming UDP port to open in the UDP_IN textbox.
10. Scroll down to Allow outgoing UDP ports.
11. Enter the outgoing UDP port to open in the UDP_OUT textbox.
12. Scroll to the bottom of the page and click the Change button.
13. Click the Firewall Restart button.