Pulled this off Playstion.com forums. Works for me and I have 2 ps2 and 1 xbox. Setup the ps2 that plays FFXI as DMZ and the other ps2/xbox I open all the ports(1-65534) for their "fixed" IP address. No more d/c's.
Your "firewall" feature could be blocking you. I have this problem on my own router. When other player's connect to me, my router thinks they are "IP spoofing" and cuts them off. I have to move my PS2 outside my firewall or just not be a 'host' for any game.
You can check this. Goto your router's administrative web page (For US Robotics, the default is http://192.168.123.254)
Check the "Status" page.
There's a log window. Do you have any message in the log indicating that it detected any attacsk, etc. ?
You can try disabling the firewall if you want. Goto the firewall page. It's under "Setup" -> "Advanced Settings" -> Firewall. You can simply click the "disable" button and save your changes.
It's possible if you're using a dynamic IP address ("automatic" configuration method for PS2) that your IP address changed and that would make your DMZ host settings wrong. It's best to use a static IP address.
Access your router's configuration screen (goto http://192.168.123.254)
Goto the "Status" screen.
Under the "Internet" heading, write down the current "DNS" and "secondary DNS" IP addresses.
Under the "Gateway" heading, write down the current IP address & network mask.
Go into the "Setup" -> "LAN" page.
What is the start & end IP? It's best not to let the router use the whole address range of the subnet. Constrain it to maybe just 50 addresses such as
Start = 192.168.123.100
End = 192.168.123.150
Now assign your PS2 to a static IP address which is NOT in that range (you'll have to re-run the NA setup utility on the PS2).
IP = 192.168.123.010
Subnet mask (netmask) = 255.255.255.000 (or whatever the network mask was which you wrote down above -- it was almost certainly 255.255.255.0)
Default router (gateway) = 192.168.123.254 (or whatever the gateway IP address which you wrote down above -- the default is 192.168.123.254)
DNS (primary and secondary) = whatever the "DNS" and "secondary DNS" addresses were that you wrote down above (from the router's status page "Internet" heading).
Now... since you picked a manual (static) IP address, it will never change. You can now go back to the DMZ screen and update the IP address (192.168.123.10 -- or whatever you used above, I used the ".10" address in my example).
Edited, Sat Apr 23 12:19:01 2005 by dubisbeast
Edited, Sat Apr 23 12:27:35 2005 by dubisbeast