I dont know how to explain it. :(
Something that can read my ip and list the ids used on that ip?
Wait, what?
I thought you ment: When somebody joins a server, their ip gets written in a file along with their blid, and maybe you could query the file and get all blid's with the same ip.
Right now you're implying that you just want something to get your ip, and automatically know what blid's have been used on it.
Which, save for Badspot, is impossible.