Re: Which backup mx method?

Ian Chilton:
> Hi,
>
> There seems to be 3 main ways of doing backup mx but I can't find any
> comparison between them - what do people here use or recommend?
>
> 1) Add permit_mx_backup to smtpd_recipient_restrictions to allow backup
> mx for any domains that have MX records added for our host.

This is for lazy sites and turns the MTA into a backscatterer.

> 2) Add the domain to relay_domains and let dns work out where to send
> it on to.

As documented this is for SECONDARY MX hosts.

> 3) Add the domain to relay_domains and add an entry to transport so the
> backup mx always sends it to a certain server.

As documented this is for PRIMARY MX hosts.
>
> (and i've been told that you should always use relay_recipient_maps as
> well as the above).
>
>
> Thanks
>
> --ian
>
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