Stunning: Determining Your Public IP

Programmatically fetching your public IP address (aka, internet visible IP) can be tough. Most often, I’ve done something silly like fetching whatismyip.com and then parsing the page. That introduces a pretty bad dependency.

Fortunately, there’s actually a protocol for asking for your internet visible IP called Session Traversal Utilities for NAT (or STUN). It’s used by services that require peer-to-peer connection negotiation (like Skype, Google hangouts, etc).

Here’s an example Ruby script that will hit up a few public STUN servers (starting with Google’s) and return your found IP: