Re: [cobalt-users] MX Records and failover servers

[Chris Bell <chris@xxxxxxxxxxxxxxx>]

At 05:49 AM 23/05/2002 -0400, Gerald Waugh wrote:
> The explanation is for a RaQ.
> You just have the secondary mail server relay for the domain.
> Thus when the primary is not available the secondary will queue messages for
> the primary.
> The primary needs two MX records one for primary and one for secondary.
> Incoming mail will be sent to the secondary when the primary is offline.
> When the primary comes back online the secondary will send all the queued
> mail


This doesn't quite work for me...

I set it up as follows:

- where domain.com is the default domain on my server; and
- mail.vdomain.com is a hostname pointing to the third party mail server;

I set up my DNS as such

vdomain.com IN A IP.IP.IP.IP (IP address of Raq server)
     IN MX mail.vdomain.com priority=5
     IN MX domain.com priority=10

If i lose a route from my local SMTP to mail.vdomain.com (which is quite 
common in Australia), it will get sent to domain.com which will then 
forward it to mail.vdomain.com, as long as it can see it. If it can't see 
it (e.g. because mail.vdomain.com is actually down as opposed to my 
connection to it), the mail bounces with an "MX loops back to me" error.

My understanding of this is that the Raq is trying to deliver it ab initio 
- it first tries to deliver it to mail.vdomain.com, when that fails it 
tries to deliver it to the lower priority domain.com, realises that this is 
a reference to itself and that it's not set up to receive mail for the 
domain, so it generates an error.

One thing I read about this type of configuration is that the MX record 
pointing to the lower priority mail server should be pointing to the 
hostname that the server refers to itself as - i.e. instead of configuring 
the secondary MX as domain.com, maybe I should have configured it as 
www.domain.com....?

I didn't find sendmail.org very helpful at all   : (


Regards

Chris Bell
BlueSkyHost.com
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