MX costs for Mail Servers.

[Kevin Darcy]

Manjunath H N wrote:

>Hi,
> 
>What is the best method to deploy MX cost on our DNS servers ??
> 
>Currently we have 3 MX records, two with the same cost(10), each is from
>a different ISP in the same geography & another MX record with cost (20)
>in a different geographical location. I feel this is a good
>configuration.
> 
>Is it better to have all the three servers with different costs or the
>current configuration is pretty robust if not what is the best practice
>for such a scenario.
>
Fundamentally, this isn't really a DNS question, it's a question of how 
to implement a robust SMTP mail infrastructure.

What you described should result in load-balancing between the two 
10-cost SMTP servers, with failover occurring to the 20-cost SMTP server 
only if the other two are unavailable. If that is consistent with your 
disaster-recovery strategy, the service levels you have promised to your 
customers, etc. then that's fine. Otherwise you may want to consider 
other options, such as having them all at different costs (failover 
follwed by failover), or all at the same cost (load-balancing across all 
three servers).

                                                                         
                                                            - Kevin