Network misery...

Giganews Newsgroups
Subject: Network misery...
Posted by:  Martin James (
Date: Fri, 16 Mar 2007

I've got this customer with a couple apps runnning.  One app is a TCP client
and the other a server.  These apps talk to each other fine in the lab and
at many other customer sites - there is nothing special about them
comms-wise, it's just a plain, low-bandwidth, TCP connection between a
couple of Delphi apps using ICS.

At this particular site, the client connects to the server OK but can then
not exchange data with it.  The client and server logs shows the successful
connection from the client.

One aspect of the connection is that the client sends 'echo' requests to the
server every five seconds, (using our protocol on top of the TCP).  The
client does not get the echo and so disconnects from the server and attempts
to reconnect - which is again successful, only to disconenct again after
five seconds.  The result is continual connect/5-sec wait/disconnect.

It appears as though the TCP connect handshake works fine but the subsequent
data exchange attempt over the 'accepted' socket-pair does not work at

The network admin is *adamant* that all firewalls/routers have been
configured appropriately.  Am I the only one who does not believe this?

Can anyone suggest anything else that might be wrong?

I am not on-site to debug this - dialogue has to be done via a 3rd-party
distributor :(.

If I cannot sort this quickly, I can feel an goat-class air ticket and
fleapit-motel coming on :((((