Re: [TCLUG:19654] Qmail and Sendmail

[mjn <mjn@umn.edu>]

On Mon, 17 Jul 2000, Adam Maloney wrote:

> 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.
> 

Seems like alot of work.  Couldn't you just add a lighter weight MX for
box1 to box2 and then shutdown box1?  From what i remember of DNS/BIND and
sendmail the secondary mailserver(box2) should receive and hold all mail
for box1 for a definible period of time or until box1 comes back
online...I could be wrong but this seems a little easier, if that is how
its going to work.

Of course this depends on how long you have qmail set to attempt delivery,
I think the default for most MTAs is 5 hours or so, but if it is just a
short maintenence it shouldn't be a problem.  

Or, if Qmail has a queuing mode, you could set up the MX and start qmail
in that queuing mode and, once box1 is back up, restart qmail normally
which should result in delivery of all the queued mail.

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

`sendmail -q' is very handy.

Later...

____________________________
Mike Neuharth
ADCS Technology Specialist
http://www.umn.edu/adcs

E-Mail		: mjn@umn.edu
Page Mail	: 6126486512@page.metrocall.com
http://nifty.dsl.visi.com/
____________________________