1. Port numbers 1 - 1024 are reserved for system services, so they're best left alone. Choose any port number >1024.

2. Allow the port through the firewall.

   $ sudo ufw allow <port>/tcp

3. Add the port to the ssh config file.

   $ sudo vim /etc/ssh/sshd_config

   In Vim, type /Port 22, which should find the same commented out. Below it, add your port number:

   #Port 22
   Port 1492       # Added by seandavidreed
   #AddressFamily any
   #ListenAddress 0.0.0.0
   #ListenAddress ::

4. Restart ssh.

   $ sudo systemctl restart sshd

5. Check that the port has been changed.

   $ sudo systemctl status ssh

Troubleshooting a problem on Ubuntu 24.04.1 LTS

6. On Ubuntu 24.04.1 LTS, I had trouble getting the default port to actually change using steps 4 and 5. Consulting an answer on Ask Ubuntu (shared above), I got the default port to change.

   $ sudo systemctl daemon-reload
   $ sudo systemctl restart ssh.socket
   $ sudo systemctl restart ssh.service

7. Check that it worked.

   $ sudo systemctl status ssh

Resources Used

• How to Change the SSH Port in Linux - Linuxize
• sshd - SSH default port not changing (Ubuntu 22.10 and later) - Ask Ubuntu