Do you use a VPN to connect to Internet and increase your privacy? If you are one of the many you would be sure that the VPN you are paying is really working properly.
You can always use, via browser, one of those dedicated websites that check your Ip and, in some cases, test the real effectiveness of VPN and/or use Terminal.
But, for my experience, if you prefer to test your public IP without using the Terminal, the best tutorial for this specific task has been published by http://www.tecadmin.net.
Get Public IP using Linux Terminal
Recommended!… if you are looking for an extra test that you can manage directly from Terminal.