It's an opensource project, and quite official. You can see it here:
http://www.mangosproject.org/forum/i...?showtopic=542
"you are not allowed to use MaNGOS for hosting MaNGOS servers for public usage."
That's why the IP is only told to friends. because It'd be illegal if I would post it somewhere in public. It's perfectly fine for Privat useage, wich includes freinds.