[Greylist-users] What timeouts should be used with greylisting

[David F. Skoll]

On Wed, 25 Jun 2003, DJ Delorie wrote:

> What I do is add a 60 second delay before sending them the error code.

That's fine on a small mail server.  It's horrendous on a busy mail
server.  You'd see sendmail (or exim or qmail or whatever) processes
backing up like crazy, chewing up your virtual memory.

Believe me, I know that adding delays to responses on a busy server
hurts. :-(

> It's not the bandwidth that's important, it's the number of emails per
> hour they send that is.

Multi-threaded spam engines on commodity hardware can easily run
thousands of parallel SMTP sessions simultaneously and probably
saturate a 100Mb/s Ethernet.  Adding delays on your end will have an
infinitessimal effect on hard-core spamware.

--
David.