Hi, >> said: 421 smtp01.example.com Error: timeout exceeded (in reply to end >> of DATA command)) > > Unfortunately, you deleted lots of useful information from the > logging, including the break-down of handshake delays and of > transmission delays.
I wasn't sure that I should post the whole queued message here. > When the receiver times out receiving data, the problem is more > likely to be at the TCP level, so no amount of verbose Postfix > logging is going to help. Ah, makes sense. > - Broken TCP window scaling support in firewall or end-host. Postfix > 2.6 and later have a main.cf:tcp_windowsize parameter. Setting > this to some value under 65536 will work around this, otherwise > you'd have to poke the kernel with sysctl or whatever. Many of the messages themselves are less than 65k. Does this make a difference? Why would it only be broken handling some messages and not others? Or is that what only tcpdump would be able to tell us? > debug_peer_list can turn on logging for specific sites, not messages. It's really more of a mail router, so only handles mail for a single domain :-( Thanks again, Alex
