So, recently I’ve been made aware, by checking my web stats and staring at web server log files for far too long, that there are certain enterprising spammers (bots?) that use anonymous proxy servers to do their dirty work.
The use of anonymous proxy servers in this way is rarely allowed by the proxy owner and tends to deplete bandwidth and processor resources rarely with any return on the proxy owner’s investment. Spammers typically use automated methods to use these resources.
Because of this, I will be implementing a CAPTCHA type system to verify the “humanness” of my proxy users. Don’t get me wrong, I know that CAPTCHA systems are not perfect but I doubt that spammers in general are going to build software into their automated spamming systems to defeat my human test. You can see an example of this type of system on this anonymous proxy site.