On Thu, 10 Aug 2006, Ken Simpson wrote:
I've had a a situation in the past that required this same application. I ended up using amavisd-new with custom views for incoming and outgoing mail. For spam originating from inside, it was dropped completely, for spam originating from the outside, subject was rewritten.
Can you elaborate on the situation off-list? It seems to me that stopping outbound webmail spam is something that would not be profitable for an ISP. I am wondering what the ISP's motivation is to solve this problem.
I'll answer on-list since this answer can benefit others. The primary reason that the ISP wants to block outbound webmail spam is because the 100s of BLs on the Internet end up blocking large segments of the IP space due to spam reporting by end users. The spammer can end up "burning" quite a few IPs before the feedback loop of user->spam report->BL->ISP->block is completed. Therefore the ISP wants to be proactive and shut off the spam before it even starts. Even if it means losing revenue. Hank Nussbacher http://www.interall.co.il
Regards, Ken
Hope this helps. -Michael
-- Michael Nicks Network Engineer KanREN e: mtnicks@kanren.net o: +1-785-856-9800 x221 m: +1-913-378-6516
Hank Nussbacher wrote:
Back in 2002 I asked if anyone had a solution to block or rate limit outgoing web based spam. Nothing came about from that thread. I have an ISP that *wants* to stop the outgoing spam on an automatic basis and be a good netizen. I would have hoped that 4 years later there would be some technical solution from some hungry startup. Perhaps I have missed it. What I have found so far is:
Detecting Outgoing Spam and Mail Bombing http://www.brettglass.com/spam/paper.html SMTP based mitigation - thing on HTTP/HTTPS
Stopping Outgoing Spam http://research.microsoft.com/~joshuago/outgoingspam-final-submit.pdf Research paper - nothing practical
Throttling Outgoing SPAM for Webmail Services http://www.ceas.cc/papers-2005/164.pdf Research paper - nothing practical
ISPs look inward to stop spam - Network World http://www.networkworld.com/news/2004/071204carrispspam.html Bottom line - no solution
So I am trying once again. Hopefully someone has some magic dust this time around.
Thanks, Hank Nussbacher http://www.interall.co.il
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