Troll trouble.. help needed!

[doomhammer]

Wasn't sure where to post this..

There is a forum I visit and periodically its visited by a user who just sends dirty pms to all the female members and then posts porn links on the site and just causes general disturbance to everyone.

My friend on the admin team told me they are unable to ban him/her because the party uses proxy servers everytime they do it so they dont know what to do. She told me all they do is ban that username.

The troll person returns with a new username and does it all over again.

So you guys got any suggestions as to how this person can be stopped?

[infamouskid]

yeah dont let proxy ip block ranges login.
you can allow proxy ip ranges to register. just dont let them login. which you should not anyways because that goes against the site terms and conditions of use agreement anyways. all users should be logged and monitored anyways to prevent this type of abuse or potential security probing risks as well. obviously this user is exploiting a security hole you guys missed.

[GroceryBagHead]

number of proxies, number of ip bans. only one is a finite resource.

[woof]

Couldn't they pre-screen new users and verify their email addresses? They would have to ban hotmail/gmail/yahoo type addresses and insist users use their real ISP address when registering.