On 7/25/2012 3:55 PM, John R Pierce wrote: > 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 ? > good question but unlikely... all the servers are in the same dmz and sit on the same switch. -- Steve