Jabber Clients on a LAN

When you use a XMPP client from a node on a LAN, where the node is NOT directly connected to the Internet; it is likely that the client would give up half way with a strange "Disconnected" message. This is because, the XMPP server at Dreamhost is not able to do a "hand-shake" back with your node, as you are located within the LAN and therefore you would have only a private IP address (Usually something like 192.168...) -- Private LAN IP addresses are not visible to outside sources.

This is how I overcame the problem:

I had a ADSL broadband ADSL modem that was connected to a switch. I configured the ADSL to accept the IP address of the Switch as a DMZ (Demilitarized Zone) and I switched off all the firewall in the Switch into the rest of the LAN. Now things are fine. But this could be a dangerous move as switching off firewall etc. would bring in viruses, etc.

I am no geek, but I understand some aspects of this and there maybe someone there who can refine my suggestions better. I think the same thing can be achieved by using NAT (Network Address Translation) but I do not know exactly how