The original message was received at Wed, 31 Jan 2007 10:48:32 +0100 from [200.199.41.184] ----- The following addresses had permanent fatal errors ----- <redhat-cz na linux.cz> ----- Transcript of the session follows ----- ... while talking to 38.156.175.18: 550 5.1.2 <redhat-cz na linux.cz>... Host unknown (Name server: host not found)