> > if you can connect to port 3050 with telnet, this means:
> > 0.) your TCP/IP are working properly
> > 1.) The port is open in you firewall
> > 2.) There is an app listening on that port
> > 3.) The App accepts the connection made by Telnet.
>

I had two systems in the past with similar issues. In my case the
first one had an old gds32.dll installed that for some reason would
not get updated. What client do you specify in IBExpert?

The second system was also Xp system that had something wrong with the
TCP/IP stack. OS reinstall fixed it :-)