Using IP addresses to block people is only good for keeping honest people out. If you want to block people properly, then demand people to be logged in with their user accounts, or moderate the anonymous forum and do not allow anonymous posts to be published until they are approved by a moderator.
You can block all my safe access points to the site, but I am not your problem Matthew.
Is there really a need on cathinfo to have a free-for-all posting feature which, if anything, could lead to the site being taken down?