Re: [TCLUG:19654] Qmail and Sendmail

[Adam Maloney <adamm@sihope.com>]

I think you could give box2 box1's IP when you take it down, but don't put
the domain name in the W class (usually sendmail.cw or grep "^CW"
/etc/sendmail.cf).  But Box2 may see the MX for box1 as pointing to itself
and return undeliverable messages, so you may want to do some DNS trickery
to fix the problem.

Say the MX is box1.domain.com, which points to 192.168.1.1.  Add an entry
to /etc/hosts for box1.domain.com to an invalid IP (like 10.0.0.1,
something that you can't route to) so that Box2 doesn't give an error like
"Mail loops back to me, MX problem?".  Box2 will receive mail for
domain.com, domain.com isn't in it's cW, so it'll try to deliver it.  The
MX points to box1.domain.com and it's defined with an unreachable IP in
/etc/hosts, so it /should/ queue the message.

When Box1 is ready, switch the IP's back, then from Box1:

telnet box2 25
220 Sendmail ...
ETRN domain.com

will send all the mail.

Or you can sendmail -q to process the queue once.

Adam Maloney
Systems Administrator
Sihope Communications

On Mon, 17 Jul 2000, Jonathan Kline wrote:

> Heres the deal: I have an email server which has an internet IP and a valid
> domain name.  I also have a second box on the same network with a domain
> name and a real IP.  The first box is teh email server for the school.  The
> second box is my private play toy... it acts as my email server and play
> server.  Generally I test everything on box 2 before I go and put it on box
> 1. We need to bring box 1 down tomarrow for some maitence, and we have no
> secondary mail server defined..... Small problem? Maybe.  Box 1 is running
> Sendmail and my box, box 2 is running Qmail.  Is there anyway to have my
> box, box 2, Accept all Mail for box 1, queue, don't try to deliver it, then
> have me manually enter a command to transfer all mail recieved by box 2 back
> to box 1?  Therefore there would only be about 2 minutes of downtime vs
> about 2 hours?  Is this to complex? I plan on changing the ip of box2 to
> match that of box if this possible!
> 
> Thanks for the input and advice.
> 
> ____________________________________________________________________________
> _________________
>   Jonathan A. Kline, A+  <jonathankl@ism-sabis.net>
>               Asst. System Administrator, International School of MN
> 
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