[TriLUG] seeking advice for a bullet-proof mail server

[Joseph Tate]

On Fri, 5 Nov 2004 09:38:17 -0500, Ryan Leathers
<ryan.leathers at globalknowledge.com> wrote:
> Does anyone have a good suggestion for me to create some redundancy using
> only two hosts?  FYI the hosts themselves are solid hardware with mirrored
> disks.  I also have LVS directors in place so that option is definitely on
> the table in addition to MX record tricks if I can just determine how to get
> the same data on both hosts.  I'm also open to suggestions other than qmail
> if there is a good redundancy story specific to some other solution.

The SMTP protocol supplies the necessary redundancy.  A secondary MX
is usually one that is contacted only if the primary MX cannot be for
any reason.  In that case the secondary queues mail and forwards it
when the primary comes back on line.  No need to synchronize content. 
I have this set up for my home operated mail server, and used it at my
last job using a 500 MHz PIII throwaway PC as the secondary MX.  Now,
if you want redundancy on the POP/IMAP end, that's a different story,
but you weren't clear on that, and in fact, in talking about MX
records you are implicitly talking about SMTP.  AFAIK the only
protocol that takes advantage of MX records is SMTP.

-- 
Joseph Tate
Personal e-mail: jtate AT dragonstrider DOT com
Web: http://www.dragonstrider.com