In the *nix world Postfix and procmail are often used for filtering out spam. Your ISP could have a file that was a table of your valid email addresses and only permit those addresses through. See http://www.securityfocus.com/infocus/1598 especially the section on "Recipient restrictions". Your ISP may already be running postfix, there's one way to find out.
Good luck -- be - MOS No guts, no glory. > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On > Behalf Of Bob Morris > Sent: Monday, June 05, 2006 4:30 AM > To: Exchange Discussions > Subject: Directory Harvesting > > I work in a country where Internet bandwidth is very > expensive. Our company is plagued with directory harvesting > spam which occupies a very considerable proportion of that > bandwidth. By directory harvesting spam I mean large numbers > of messages sent to <random-fictitious-user>@<real_domain>. > > It would seem to me that it would be possible to install some > kind of Active Directory aware filter at the ISP end of our > link which would simply drop such messages down a hole and > forward only those with genuine mailbox adresses. We have > internal anti-spam software which can handle the "genuine > spam" adequately. > > Looking through the literature it would seem that maybe using > C# code to hook into the MS SMTP categorizer sink would do > the trick but it seems to me that someone must have tackled > this problem already. Also in view of the known proclivities > of the ISP a Unix family solution would be useful. > > Any suggesions will be most welcome. > > Bob > > _________________________________________________________________ > List posting FAQ: http://www.swinc.com/resource/exch_faq.htm > Web Interface: http://intm-dl.sparklist.com/read/?forum=exchange > To subscribe: http://e-newsletters.internet.com/discussionlists.html/ > To unsubscribe send a blank email to > [EMAIL PROTECTED] > Exchange List admin: [EMAIL PROTECTED] > To unsubscribe via postal mail, please contact us at: > Jupitermedia Corp. > Attn: Discussion List Management > 475 Park Avenue South > New York, NY 10016 > > Please include the email address which you have been contacted with. > > _________________________________________________________________ List posting FAQ: http://www.swinc.com/resource/exch_faq.htm Web Interface: http://intm-dl.sparklist.com/read/?forum=exchange To subscribe: http://e-newsletters.internet.com/discussionlists.html/ To unsubscribe send a blank email to [EMAIL PROTECTED] Exchange List admin: [EMAIL PROTECTED] To unsubscribe via postal mail, please contact us at: Jupitermedia Corp. Attn: Discussion List Management 475 Park Avenue South New York, NY 10016 Please include the email address which you have been contacted with.
