Hi,
Could also be a routing issue (no route to host).
From you DMZ linux machine, I suggest you try the following
-check your network setup (/sbin/route -n), in particular that the IP of your gateway is properly configured
-check if the IP (I mean ipaddress, not nework name) of the remote machine is visible. Try goold old ping, if the firewall does not block ICMP, or try checking the port at the same time, try one of the following:
telnet ipaddress 3300
dig ipaddress
nmap ipaddress
If all fails, it is likely that either your gateway is not properly configured, or that an intermediate firewall filters packets going to port 3300 (would be my bet). Also does the connection use UDP or TCP packets? -check that the firewall does not block the one needed.
bruno