TCP/IP connectivity via DataSnap

Question

I wrote a multi-tier application suite in Delphi XE, using DataSnap (VCL application).

This will be used internally, in my company, mostly to replace the outdated fax communication.

Everything works fine, but I came across an unpleasant situation: The server machine is behind a router, so it has an internal network IP. I forwarded (in the router) all incoming connections on port 211(DataSnap default) to the server's internal IP and about 8 times out of ten all the clients connect to the server without any problems.

The problem is that for the rest 2 times I get all sort of connection errors (mostly connection timed out). When it does this I have to close and reopen either the server application either (some of) the clients, and then it works.

Right now I'm still in the design phase, so it's only a bother, but when I do release it I don't want either to tell everyone NOT to EVER close the application (once it works, it works, no more problems), either close and reopen the applications each time there is a connection problem.

How can I eliminate this problem?

I had (only) a look at NetCat and SoCat, but (to me) it seems overkill for this situation. Is there another way to solve this?

Answer 1

The solution was switching off router's internal firewall.