How do I limit the amount of guests viewing my forum?

[dagummit]

Okay, I have a relatively small forum (around 50 members on at one time) and yesterday for whatever reason (DDoS?) I had over 200 guests accessing the site... I had a lot of lag because of that.

I have searched around and see that there is a way to limit the number of guests or a ratio of guests to member thingy on vB, but can't seem to find out where to set this at in vB...

Can someone direct me to the place to change this setting?

[tobybird]

Sorry, I know this doesn't answer your question, but you sure they weren't spiders? The Slurpies tend to come in in pretty big waves. At least that's how they are on my site...

eta: Oh and if they were spiders you can simply block or limit them with a robots.txt file. http://www.robotstxt.org/wc/exclusion-admin.html