On Thu, 30 Aug 2007 at 10:29:40PM +0100, Wayne Lee wrote:
> Hello All
>
> We have recently taken over another company and all their servers, the
> main mail server which is running sendmail is being hammered.
>
> We are using RBL lists, greet pause and have max children set at 300
> which is constantly being reached. I have also blocked a lot of /16's in
> the firewall but we are still struggling. I have tried to use hermes for
> greylisting but this has proved to be unstable and pisses off the users.
> The problem has been getting worse all week.
>
> I'm in the process of installing postfix on Etch and will migrate but
> will this help?
I can't comment on the Sendmail/postfix end of the equations as I use
Debian's Exim default, but a friend found that filtering before via
the firewall is quite effective - you may have to get more aggressive
that you currently do to make it work.
A good *BSD solution is to throttle all SMTP requests originating on a
Windows systems, the OpenBSD firewall can do traffic shaping based on
the OS sending the packets, I don't think ipfilter/iptables can yet.
A friend also rejects almost all email sent to his primary MX address,
and only accepts email at his secondary. Most spammers don't fall back
to the secondary
--
Adam Trickett
Overton, HANTS, UK
A people that values its privileges above
its principles soon loses both.
-- Dwight D. Eisenhower
