Re: [Exim] random bounces

> We always use a local caching nameserver in our configurations - actually
> we have two main nameservers, one which "faces inwards" [which knows
> authorative answers for all our domains plus local bits we don't want the
> internet at large to see] and one which faces outwards and does real
> resolving.
>
> The mail hosts talk to the inner nameserver which forwards requests to
> the external one, the inner nameserver has a config in the form:

Note that this can lead to trouble if domains are moving to you or
away from you. Caching name servers are indeed _very_ helpful for
performance, but if your inner server feels authorative for a zone that
moved to a different provider, mail may be sent to the wrong host.

Michael