Not allowing certain email domains to register

[AntonyF]

Originally Posted by Bilderback

There is an option in the vBulletin Options -> User Banning Options
which allow current users to keep their banned registered emails.
So you can set no new registrations using gmail and allow current members to get bypassed.

I did see that, but was confused... I thought it'd allow a banned member to keep it so didn't understand. Will give that a go, thanks for the replies.