The original message was received at Thu, 17 Jul 2014 10:29:58 +0530 from 73.28.108.230 ----- The following addresses had permanent fatal errors ----- <dev at openvswitch.org> ----- Transcript of session follows ----- ... while talking to 217.137.70.153: 550 5.1.2 <dev at openvswitch.org>... Host unknown (Name server: host not found)