Banning Hostnames during registration

[angelo]

I read somewhere that vbulletin doesnt have the ability to ban hostnames in the banning options because it would be too server intensive going through every hostname to match if it has been banned, but could someone make it so that administrators can disallow a certain hostname from registering...this would be really helpful, and it probably wouldnt be server intensive because it would only run a db query when someone tries to register. im not sure as to how difficult this would be, but it would help out A LOT of people that run forums.

thx