In Internet-speak, a proxy is a server that takes your request, sends it to a destination server as if it were coming from the proxy itself, and then sends the response back to you. It acts as a proxy in much the same way that you can use a lawyer as an intermediary or designate someone else to cast your vote at a stockholder meeting. Internet proxies can be used for a variety of purposes, one of which is anonymous browsing.
An anonymous proxy keeps no permanent record of which users have connected to which websites. And since the page request comes from the proxy itself, there is no easy way to track who is actually making the request. (In reality the use of multiple, chained proxies is recommended.) This anonymity is quite beneficial for whistle blowers and victims of political oppression, as well as the privacy- and security-conscious. But it also works for organized crime, terrorists, and other criminals.
Another popular use of proxies (not necessarily anonymous ones) is to circumvent corporate/government filters. The destination website may be blocked, but the proxy server is not—thus allowing the user to view prohibited websites.
Here are additional resources:
- Anonymouse.org and the associated Firefox add-on
- Anonymous Internet Surfing HOWTO
- Public CGI (Web, PHP) anonymous proxy free list
- Tor (warning: Tor is not secure, and don’t even think about hosting a Tor node)
Thanks to Josh for this topic and the links.