Tomasz K. Jarzynka:
> Finally, I ran a tcpdump on our origin mail server, our firewall
> and the destinantion mail server (thanks to the help of its
> administrator) but the output is inconclusive to me. On our side,
> It looks like transmission stalls after a couple hundred bytes +
> subsequent retransmissions eventually leading to a timeout. On
> the destination side, it looks like the connection is ended
> immediately after the start of transmission.
Google for
1 - IP path MTU discovery.
2 - TCP window scaling.
Wietse
