ReverseDOS Spam Filter Installed

Just because I disabled trackbacks on my site doesn’t mean the traffic hasn’t continued to pour in and sap my bandwidth.  So after some hunting around I found this nifty tool which in essence tricks would be spammers into thinking your site is overloaded, and hopefully they’ll disconnect.  From the website:

ReverseDOS is a very simple HttpModule that checks various parts of incoming requests against a list of crap that you don't want pushed on to your site. If ReverseDOS detects a match, it attempts to stall the requesting client for a number of seconds (specified in a .config file). During this loop, which uses virtually no server resources - and only a tiny smidgen of bandwidth, ReverseDOS checks every .3 seconds to see if the client is still connected. If the spammer disconnects, good riddance. If the spammer sticks around, they're finally rewarded with the Response Headers - containing an HTTP 403 - Access Denied Response Code.

In addition to the binary download, the author also has a full source download.  Already within the couple of hours I’ve had it installed I’ve seen a decrease in the amount of bogus requests, so obviously it really works.  This is a great solution because it stops spam at the source (packet level) which frees up bandwidth, CPU cycles, etc as the message never even reaches the machine (assuming the spammer disconnects, which they usually will when faced with a repeated number of 403 errors).  It’s actually quite elegant when you think about it (and certainly much simpler than building a blacklist in your database or whatnot), so a job well done award to Michael Campbell for this fantastic tool.  Hopefully I can re-enable trackbacks soon after a few days of monitoring.