Board Thread:Support Requests - Community Management/@comment-26367235-20140506123922/@comment-5454372-20140506135614

This link might help a bit. From what I'm seeing, blocking "59.101.0.0/16" looks like it'll do the trick for you, but that looks like a rather large range at a glance (it knocks out everything from 59.101.0.0 to 59.101.255.255 -- potentially up to 256^2 IPs, I think).

If you're going to try an IP block, might be an idea to make it temporary -- or better yet, set it as an infinite block, and then remove it at your own discretion at some unspecified point (that way, the vandal in question doesn't know how long he'd have to wait until it comes down).