204,006 attempted registrations in one day
 

We've developed a spam bot problem, it seems. Today alone, we had 204,006 attempted registrations. Thankfully we have a very good registration process and none have actually been able to get through, but it's still slowing down the server.

Is there a plugin that would consult a spammer blacklist or something and block these clowns? I'd appreciate any help,or just a point in the right directions.

Sounds like a DDoS attack to me.

If you can determine something unique in the user agent string being used, you can block it with Simon Lloyd's "Ban spider by user agent" Mod.