mark anderson lssdiscerningcom everything cool cgi domain1org sends email pvosgprdomain1org everything mostly cool also domain2org sometimes email rejected destination messages like 554 554 relaying denied ip name lookup failed ip1 ip1 actual ip address destination doesnt like fact seeing email domain2org sent ip address domain1org evidence recipient domain requires would stupid rule post log lines showing guilty party exact reject message actual cause likely something else may need contact postmaster recipient domain find requirements go nothing changed except local part destination domain solidarityforafricaorg 6485161177 postfix binding different ip host 6485161176 assume rrcom liking feb 14 134848 b02s01mr postfixqmgr27946 f1757930065 size515 nrcpt1 queue active feb 14 134849 b02s01mr postfixsmtp13874 f1757930065 host hrndvasmtpin01mailrrcom717456243 refused talk 554hrndvamxlbmailrrcom 554 554 relaying denied ip name lookup failed 6485161176 feb 14 134849 b02s01mr postfixsmtp13874 f1757930065 relayhrndvasmtpin02mailrrcom71745624425 delay54985 delays54983001140 dsn400 statusdeferred host hrndvasmtpin02mailrrcom717456244 refused talk 554hrndvamxlbmailrrcom 554 554 relaying denied ip name lookup failed 6485161176 tue 05 aug 2008 180052 0800 arrange outgoing email sent correct outgoing ip