This was posted via an anonymous proxy. It should be possible to detect and block them, however you have to maintain a list of proxies, which may well be constantly changing.

Code here for one way of coping with the problem.

But there's not much you could do about dial-ups I don't think.

In case anyone thinks anonymous proxies might let you look for illegal material on the web, consider that you're much safer in the hands of the CID/FBI than the mafia.....