[CentOS] DNS lookup delay with centos & postfix

Wed Jul 25 21:55:16 UTC 2012
John R Pierce <pierce at hogranch.com>

On 07/25/12 1:57 PM, Steve Lindemann wrote:
> Anyone have any ideas for why nagios would have trouble testing smtp on
> the email server when the primary dns goes offline?  I'm not even sure
> where to look or who else would make sense to ask the question of on
> this one.  I'd appreciate any insight anyone out there has on this.

DNS lookups default to using 53/udp, and only use 53/tcp for zone 
transfers.  could it be 53/udp is being lost/blocked between this host 
and your ns1 ?

john r pierce                            N 37, W 122
santa cruz ca                         mid-left coast