Rolf E. Sonneveld:
> On 02/11/2013 11:36 PM, Wietse Venema wrote:
> > Rolf E. Sonneveld:
> >> In general, Postfix is running fine and this Postfix instance is also
> >> running fine. However, there is one SMTP client (of which we are not in
> >> control), that sends messages with long lines to this server running
> >> Postfix. There is a problem with the communication between this client
> >> and the server: whenever the clients sends a message which includes one
> >> long line (377 characters, excluding the CRLF), the client seems to
> >> 'hang' after character # 256 of this long line is transmitted. Then,
> >> after some time the connection times out.
> > A tcpdump recording will reveal if the client stops sending or if
> > the server stops reading (it's revealed by TCP receive window size).
> > Once this is known the search can be focused. It could be somethinh
> > as stupid as poorly-implemented anti-virus software.
> > http://www.postfix.org/DEBUG_README.html#sniffer
> thanks for your answer. I did a tcpdump for the session but when
> analysing it, I could not find a clear cause.
Based on the bits on the wire it is 100% clear whether the client
stops sending or whether the receiver stops receiving. Just look
at the TCP window.
> At the end of the day, it
> appeared to have been a cli/tty related limitation (of Solaris?). See
> for a discussion
> https://forums.oracle.com/forums/thread.jspa?messageID=8292168). When
> sending the same data using a perl script it worked without a problem.