[Centos] *very* raw script for a new email server

Wed Dec 8 19:47:41 UTC 2004
Ajay Sharma <ssharma at revsharecorp.com>

Eric Sorenson wrote:

> If you have two physical machines, the old one and the new one, you should
> take your time and set up the new one by hand (rather than by script), and
> maybe plug it in side-by-side with the old one, without the public IP
> address that the world is talking to. When you're ready to cut over,
> 'ifdown' the old one, 'ifup' the new one, and run your tests. If your
> tests fail, depending on how bad the failure is, you can decide to roll
> back to the old server by reversing the process or fix things "live".

I can second this notion.  If you have the extra hardware doing the 
network IP switch is the best way to go.  I try to have every machine 
with two IP addresses.  One for the physical machine and one for the 
"service".  So is the physical mail server but 
is the "mail.domain.com" address.  That way I can setup a new server, 
configure/test it.  Then when it comes time to switching over, I just 
turn off the alias on the old server, and turn it on on the new server.

Our company went from a sendmail server to a postfix/clam/spamassassin 
setup over night using this method.  The only difference to the staff 
was all their spam was filtered.