Redundant Mail System Suggestions

Randal, Phil prandal at
Wed Nov 28 10:06:37 GMT 2007

Use two mx servers at the same priority.

Otherwise you'll get most of your ham going to the first box, and most
of the spam to the second.

In that case, Bayes will be terrible on the second box because it will
be starved of ham.


Phil Randal
Network Engineer
Herefordshire Council
Hereford, UK  

> -----Original Message-----
> From: mailscanner-bounces at 
> [mailto:mailscanner-bounces at] On Behalf 
> Of Johnny Stork
> Sent: 27 November 2007 18:20
> To: mailscanner at
> Subject: Redundant Mail System Suggestions
> I am working with a client seeking redundant mail and dns services so 
> have been trying to come up with some suggested architectures.
> client has dual internet connections. So my first thought was 
> create two 
> identical MS/MW (mailscanner/mailwatch) systems, and assign each a 
> different MX record with one being higher priority than the 
> other. The 
> machine running MS/MW would also be a DNS server so what would be the 
> best way to setup some redundancy for both DNS and incoming mail?
> Primary MX Record (Internet connection 1)
> Secondary MX Record (Internet connection 2)
> What are the benefits/differences between creating a  single A record 
> with the same hostname, but the two different IP's above, versus 
> multiple MX records but all with the same/different priority? 
> Or, just 
> list the machines as seperate MX records with the same priority?
> The next step is how to I ensure that the MS/MW systems on 
> both servers 
> remain synchronized? I can easily point them to a common 
> Mysql database 
> which will be running internally and will be redundant by way 
> of a RH HA 
> Cluster, but what about the mail user accounts? The client will be 
> running an internal groupware solution, possibly Scalix, so all mail 
> coming in to the gateway MS/MW servers will simple get 
> forwarded with a 
> mailertable entry so is there any need to synchronise anything else 
> between the two gateway MW/MS servers?
> If anyone has any other suggestions/ideas for setting up such an 
> environment I would be greatful.
> -- 
> *Johnny Stork*
> Business & Technology Consultant
> stork at
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