REQUEST: Network Interface Failover and multi-DNS resolution

[Roland McGrath]

> OK. Maybe so. But I think this is a valid bug based on my observations of the
> same phenomena. If a machine has ns1 & ns2 listed, ns1 cannot get out to the
> internet temporarily and returns an error, the whole mail system comes to a
> stop...even though ns2 is working perfect.

That is how resolv.conf is supposed to work.  It lists nameservers, and you
get the first one that is available, i.e. answers at all.  If you want more
complicated logic, that does not belong in the resolver used by applications.
Use a local caching nameserver that implements the fancy policy you want.