Author: Chris Huff Date: To: exim-users Subject: RE: [Exim] dual redundant server setup
thanks for the advice everyone. I think Ill just go behind our load balancer until I have time to read more on exim. The reason I didnt want to go behind it before was b/c it was a single point of failure but I guess thats the network guys problem ;)
.. I wish I could set something up with pf, love that firewall!
Lee W wrote:
> I want to install a more redundant exim setup at work. Im not sure about one
> thing though. If I want dual email servers running at the same time behind
> firewall or just on the internet, do I have to make the MX record for both of
> them weighted the same?
We use a single MX record which points to an appliance load balancer.
This load balancer rotates the SMTP connections between three "border"
MXes, which do UCE filtering and virus scanning. These MXes then
forward the mail to a single internal mail server (also running Exim)
for local delivery. This internal mail server was built on
highly-redundant hardware. The idea behind this arrangement is that we
put a lot of mail machines out front so that incoming mail reliability
is high. Once mail makes it to these servers, it doesn't matter much if
our internal (behind the border servers) T-1 line goes down or if the
internal mail server goes down because the border servers will queue the
mail.
We use an Alteon AceDirector 4 for the load balancing but there are many
good load-balancing solutions available now that utilize commodity
hardware running OSes like FreeBSD and OpenBSD.
