Wietse Venema put forth on 5/28/2010 9:37 AM: > Ioannis Tsouvalas: >>> >>> Ioannis Tsouvalas: >>>> 451 Requested action aborted: local error in processing >>>> 451 Temporary local problem - please try later > > These you can do nothing about, except perhaps retry when the remote > system is under less stress. > >>>> 421 4.4.1 Connection timed out (in reply to end of DATA command) >>>> 421 4.4.2 mxfront39.mail.yandex.net Error: timeout exceeded (in >>>> reply to end of DATA command) > > These could be a network-level problem such as broken IP path MTU > discovery, or TCP options that are mis-implemented by an and system > or by an intermediate system (such as a cheap firewall).
IIRC from his initial post, Ioannis has 3 virtual machines atop ESXi: one a dedicated Ubuntu Shorewall instance, one running Ubuntu Shorewall (again) and Postfix, one running Microsoft SBS plus Exchange. A basic network diagram would be helpful at this point, although out of the scope of Postfix. At first glance this network setup seems an unnecessary mess of "geek toys", wrought with unneeded complexity for the sake of "neato!" complexity. Tandem packet firewalls across VMware guests? Ioannis, disable all the firewalls but for basic SPI NAT/PAT (if you're using NAT) on the dedicated Shorewall guest. Route TCP 25 inbound via a PAT rule to the Postfix guest. See if that eliminates the timeout and related TCP errors. -- Stan
