[CentOS] Slow domain resolution problem

On Mon, Aug 23, 2010 at 11:08 AM, Gabriel Tabares
<gabriel.tabares at roboreus.com>

> One more thing, if this is the case, why does the nslookup respond
> straight away? Is the destination server trying to somehow validate the
> host where the connection came from?

It's entirely possible (and probable) that the mail server is
attempting to do a reverse looking up the originating host. When the
lookup times out, the connection goes through.

If the command

ping my-mail02.mydomain.com

returns immediately with data, that would support that theory.

M