firewalls and GPRS

Hi Guys,

This may be a bit off-topic, but I need the help off the best firewall
experts I can get ;-)

I want a process-computer, somewhere in the field, to communicate with
a central computer. They use a dedicated protocol, now packed in TCP
or UDP messages.

The process computer is connected via a GPRS-modem with build in IP
stack. The only thing I can do is setting up an the connection (TCP or
UDP) an get my data via the RS-232 port. Because off cost issues I
want to communicate only is necessary. The initiative of this
communication is sometimes with the central, sometimes with remote
device. The initiative for the connection is always with the remote
evice, because of the dynamic IP addresses for GPRS.

Now my problem. At the central site a hardware firewall is used. This
drops the connection at certain time. Both for UDP and TCP. Is there
any way to keep this connection open? Or is this normal firewall
behavior without any solution. Is it because this kind of
communication differs from normal web serving behavior?

In short, ant tip and trick is welcome!
I'm counting you experts... :-)
Received on Mon May 1 00:54:08 2006