Tomasz Iwanowski: > Hi All, > > I manage a local intranet mail server which collects mails from our local > users > and sends them all via our public mail hub server. > > Everything was fine until few weeks ago. Some small part of our emails (about > 10%) hangs > in mail's server queue with error: timeout exceeded (in reply to end of DATA > command)). > Some emails stay in queue untill timeout expires (3 days) and returns to a > sender with error. > There are emails which stay in queue for a few hours (with the same error) > but after serveral retries finally leave our server and reach recepients. > > Noticed following facts: > - every timeout error is: (in reply to end of DATA command), there are no > other errors > - problem does not depend on email size (there were delayed emails with size > range from 1kb to 5mb) > > Turned off: tcp window scalling, tcp ecn, smtp_connection_cache_on_demand - > without success. > > In my opinion problem is on the mail hub server but I have no proofs. > Talking with mail hub server's administrator but he said, that no others have > problems with mails > and that must be a problem with my email server. > Now I stuck with my undelivered emails.
Try collecting a tcpdump recording. http://www.postfix.org/DEBUG_README.html#sniffer Command: # tcpdump -s 0 -w /file/name host server-ip-address and port 25 After some time, "kill -INT" the tcpdump process. Look in the logfile for a session that breaks, and find that session in the tcpdump recording. # tcpdump -nr /file/name | less Note the client tcp port, then extract that session: # tcpdump -nr /file/name -w file/name2 port xxx Then, contact Victor or me off-list. Wietse
