Re: [exim] Strange log entry about backup MX

Chris Wilson, 2010-06-16 13:48:

>> relays was blocked on my mailserver because it connected to the second
>> MX without trying the first one before...
> For the reasons that Heiko and Graeme gave, I would strongly recommend
> against blocking anyone on this basis. (i.e. there could have been a
> temporary problem when they tried to contact your primary, so you might
> not have knowm that they tried).

The things said about such a setup do not apply here. As I wrote, the
two MXs resolve to IPs ending up on the same host. They are even
connected via the same physical network. Even in the very unlike case
that there is a transient problem at the time of the connection attempt
to the first address, which does not exist at the time of second
attempt, the delivery will be retried again, multiple times.