How do you stop outgoing spam?

Mon Sep 9 10:49:52 UTC 2002

On Mon, 9 Sep 2002, Hank Nussbacher wrote:

> The spamming is usually done (but not only) from an Internet cafe where the
> spammer inserts a "spammer CD" and blasts away at open mail relays.  When
> SMTP is blocked for that IP, they switch to HTTP and send the spam via MSN,
> Yahoo, Hotmail, Kukamail, Outblaze, Safe-mail, etc. to name just a
> few.  Blocking port 80 is harder since it requires maintaining an ever
> larger list of free public web based mail systems or just block port 80
> entirely.

You could traffic shape or rate limit the traffic towards port 80 to a few
kbps for each IP address that might be used for spamming. If you allow
small bursts (10 - 50k) this should be just fine for regular web access,
since for that outgoing traffic is minimal: just the HTTP requests and
ACKs. However, it will slow down spamming to at most a couple dozen spams
per minute after the first few that fill up the configured burst size. I
imagine this will make the spammers move on to greener pastures.