sshd.md

Update your firewall rules to allow the new port. If you're using UFW:

ufw allow <new_port_number>/tcp
ufw reload

1. Run the following command to edit the SSH socket unit file:

EDITOR=vim systemctl edit ssh.socket

2. This will open an editor with an empty file. Add the following lines:

[Socket]
ListenStream=
ListenStream=<new_port_number>

The line ListenStream= is required that port 22 is no longer used. Without this line, the SSH server would then be accessible via port 22 (default) and <new_port_number>.

3. Save the file and exit the editor.

4. Reload the systemd manager configuration

systemctl daemon-reload

5. Restart the SSH socket

systemctl restart ssh.socket

6. Verify that the new port is being used:

ss -tlnp | grep ssh