For what it is worth, I have found that the STUN protocol is also an option for discovering this sort of information. There are lists of public stun servers out

For what it is worth, I have found that the STUN protocol is also an option for discovering this sort of information. There are lists of public stun servers out there [0]. Finding a client is a little more difficult than just using curl, I grant, but not impossible. [0]: https://gist.github.com/mondain/b0ec1cf5f60ae726202e https://gist.github.com/mondain/b0ec1cf5f60ae726202e