[CentOS] Centos 6 Sendmail backup MX Config

[Always Learning]

On Fri, 2015-02-13 at 11:04 -0600, Les Mikesell wrote:

> I'd recommend not having a secondary MX at all unless it is equipped
> to reject invalid users and spam in all the same ways as your primary.
>   Otherwise it accept junk that your primary rejects and then you are
> obligated to send a bounce message which is always a bad thing - you
> want the authoritative receiver to reject at the smtp level instead of
> accepting at all.  There's a whole category of spam where the real
> target is the apparent sender where a bounce will go.  Also anything
> sending valid mail should be prepared to queue and retry on temporary
> failures just as well as your own secondary would.

On some domains I have 3 MXs - primary, secondary and tertiary - all
share exactly the same coding, configuration and reporting. Absolutely
no sense is weakening security for any MX although some spammers think
the highest numbered MX is the weakest !


-- 
Regards,

Paul.
England, EU.      Je suis Charlie.