Preventing new registrations from an IP range while preserving current users?
 

Hi all,

Does anyone know if there is a mod which would enable me to prevent new users registering accounts from an IP address range while allowing already registered users who use that range to continue to log in and use the forum?

Here's the scenario:

I have an IP range which is used by spammers and was blocked. Unfortunately I also have a valuable forum user who is in that range on a non static IP, so when they log in to the boards their IP will always be somewhere in that IP range.

What I'd like to do is prevent new users from creating accounts in that range, without limiting the access of the current user.

Any suggestions greatly appreciated!