SSH
Changing the default ssh listening port
By default secure shell (ssh) listens on tcp port 22. If you want to obfuscate it by changing the listening port from port 22 to something else like port 31337, you can do so in /etc/ssh/sshd_config.
You can use your favorite text editor (e.g., vi, gedit, nano, emacs) to edit /etc/ssh/sshd_config, but for the purpose of this example vi will be used.
sudo vi /etc/ssh/sshd_config
Change the Port setting from 22 to 31337. Then restart the ssh daemon so that it will now start listening on port 31337:
sudo killall -HUP sshd
Verify that ssh is listening on the new port:
netstat -nltp | grep sshd
Allow the new ssh port in the firewall:
sudo ufw allow 31337/tcp