Spam filtering usin proxy server.
I've been messing around with spam filtering with varying degree's of success now for a few weeks. out of the 200 spam emails I get a day, 190 are caught and about 10 get through to my mail box. considering the amount that get's caught I consider it to be reasonably successful.
However I would hoped, although rather niavely that the level of spame emails would have started to drop but it seems to be remaining constant at about 200 a day.
I believe that a lot of spammers use transparent gifs so they know the email is valid. I have setup a proxy server for all my http connections and a firewall. I was wondering if a list of domain names or url's exist of the urls used for this so I can get my proxy to block it or redirect it to a 404 page.
I've tried searching with google but the second you stick the words proxy and spam in there you get loads of results but nothing which can point me in the right direction.
Thanks for any help