ShowIP created around 1998 was a popular app between the years of 2000-2012. It’s still (8+ years after being abandoned) listed on several download sites where one of them is Softpedia. Link below.
I’m developing this app again from scratch. Although I’m not aware of any need of such an app nowadays to be honest, because now we have websites doing the same job (https://www.whatsmyip.org/) but I’m doing it anyway. Some might prefer a tiny little app sitting in the SysTray where you have immediate access to the information.
Next I’m planning to make a Tweaking app for Windows 10 (Tweak’n Win) for tweaking OS settings.