A group of "nice" people are paralyzing my forums by refreshing the pages for a long long period of time.

I wounder if there is a hack or a tag or any way to prevent refreshing pages for ever

As far as I know there isn't one now.

I can't see this being particularly easy to implement without using something with the apache config files I'm afraid.

Even if there was a hack it wouldn't help you...

Page Requests are handled by Apache and even if vBulletin denies the page it would have to return something to Apache which would still eventually use your bandwidth.

You will have to use something like Apache's mod_rewrite to forbid those IP's from having access.

p.s. a SYN attack is usually characterized has having your machine overwhelmed with large amounts of very large UDP packets. These packets usually contain garbage.