It looks like some folks are hosting proxies on Google's AppEngine.

I noticed when I caught it doing naughty things to one of my web sites. Unfortunately, I cannot easily IP block it because it's IP is within Google's IP address space. It attacked from, which is part of Google's range.

I found a good writeup on Labnol about how to do this, Setup your own Proxy Server in 5 Minutes for Free.

What do you think?