The trouble with NAT

There was a forum topic earlier this week on Edugeek (a very good site, recommended) concerning a user who was at college and he had lost access to some online forums. This was because his college uses NAT to allow the many PC's on their private LAN to access the Internet simultaneously. The forum admins had banned the IP of the problem user but because all the users at the college appear as coming from one IP the forum admins had effectively banned the entire college from their site. Naturally he had contacted the admins to re-establish access. They apparently declined.

I personally have seen the same problem on Wikipedia. IP bans are quite common for 'anonymous' editors who vandalise and blank pages. In fact I raised this issue not long ago with our LEA because the proxy servers the schools used were blocked from editing. There is little that they can do of course. Happily with Wikipedia it's possible to get round the editing ban by creating a user account. Any edits will then be attributed to the account and not the IP even the IP is blocked from editing.

I suspect NAT will be with us for a long time to come and this is one of many unfortunate side effects. Of course it has it's advantages for sharing the Internet and providing security for machines behind the NAT gateway. But it really isn't the way the Internet is supposed to work. A lot of software (Video conferencing, Instant Messaging, VoIP, P2P apps like Bit torrent for example) assumes end to end compatibility which has to be hacked around to work with NAT.

Roll on IPv6!