OT: Backup MX

Dennis Willson taz at taz-mania.com
Wed Sep 13 19:02:24 IST 2006

Actually running a backup MX is a good thing. You can multi-home the 
backup MX (I refer to this as a mail hub), This hub is setup as a 
lower priority MX, then it would be setup to forward all email for 
your domain(s) to the real server via the second interface. The hub 
should not have to know anything about users.

I have a setup where I have two hubs that forward to the end user mail 
server. The end user mail server never directly receives email from 
the internet. All Spam filtering is done out at the hubs so the server 
the users deal with has all its CPU power to handle users requests and 
they see good response times from the server regardless of how much 
load the hubs are under due to Spam scanning/filtering.

While a lot of people know this.... remember the DSL line will need a 
static IP address.

On Wed, 13 Sep 2006 09:33:19 -0400
  "Green, Rodney" <rgreen at trayerproducts.com> wrote:
>Green, Rodney wrote:
>>Green, Rodney wrote:
>>>We recently had a day of downtime for our Internet connection. We 
>>>don't have a backup MX to queue mail while our  mail server is 
>>>My question is this. If I were to get a DSL connection setup and 
>>>connect a backup DNS server and backup MX server, would there be a 
>>>for users to access incoming mail that is queued on the backup MX? 
>>>How is something like this normally handled? We rely on e-mail here 
>>>need some sort of backup plan if our main connection goes down.
>>>Thanks for any suggestions.
>>Just to add a little more information.. I'm using postfix as our MTA 
>>and of course MailScanner.
>Replying to my own post yet again. :-)
>I think my answer is in how DNS and MX records work. I guess I was 
>confused by the term "backup mx." It looks like I would need to setup 
>a duplicate mail server on the DSL connection, with a different FQDN, 
>of course, and set it up as a final destination for mail. Then in DNS 
>I would set up that new server with a lower priority than the normal 
>server. If the primary server is down mail should then be delivered 
>to the server on the DSL connection and be accessible to the users 
>with a simple configuration change. Does this sound correct?
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Dennis Willson

taz at taz-mania.com

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