Port Scanner for Open Proxies on Registration

[beano33]

Anyone with a good sized board knows what a nuisance proxies can be in the hands of disgruntled users and revolutionary wannabes. The only hacks to deal with this use http forwarding, which doesn't detect anonymous proxies, so they're very limited in value. Just about anyone that's going to go through the trouble of using a proxy to evade a ban is going to use an anonymous one.

The only way I can think of to deal with it is to do port scanning at registration, similar to what is done on IRC servers. I know it's server intensive, but I'm wondering if it would be that bad if it were only used to scan registration applications?

The features/options I'd like to see:

1) port scan: ports 80, 81, 3128, 8000, and 8080. I think these are the most common, someone can correct me on that if I'm wrong. Chances are one of these will be open even if the user is connected to a less common one.

2) automatically reject the registration: with a message for the user. It could be integrated into email verification. I assume anyone that has need for a proxy scanner is already doing email verification.

3) automatically ban the IP using vBulletin's IP ban to the 2nd depth: example- if the IP is 219.202.64.47 the hack would write 219.202.64. to your IP ban list. Eventually with all those open proxies being auto-banned, the malcontents would give up. This way would also easily allow you to manually remove a ban as there's bound to be glitches and special circumstances. Ideally this would be an option that could be turned on and off, but I know I'm asking for too much already.
:nervous:

4) Create a log of rejected registrations due to open open proxies. vBulletin owners could share these and speed up the process.

This looks like it would be a major hack, so anyone with the ambition to do it is bound to become famous.