Situational FFXI-4001/2 Follow

Hello. Let me explain the situation. We have two computers which are connected to the same internet connection, Computer A and Computer B. Computer A often disconnects from FFXI and receives the FFXI-4002 or FFXI-4001 error code. The internet connection is otherwise fine and can browse as normal. Computer B, however does not disconnect with these errors. It did originally, until used a DMZ on Computer B, now it no longer disconnects. But unfortunately I cannot DMZ both computers. I tried to do Port Forwarding to Computer A, but this does not seem to work. Any body have any thoughts about this?

I pretty sure it's router related. Is there anyway I can configure the router to allow both computers to not receive this error instead of just one? We have a Belkin F5D9230-4. If more information is needed, I'll provide it. Thanks!

Thanks for the reply. I did try port forward the correct ports by using the guides at portforward.com. The exact guide I used was at http://www.portforward.com/english/routers/port_forwarding/Belkin/F5D9230-4/Final_Fantasy_XI_-_PC.htm . However, as you may imagine, it will only let me forward the required ports for FFXI to one of my computers. Even when I forwarded the ports to one of my computers without the DMZ, both computers would get the 4001/4001 errors at the same time. So it seems as if the portforwarding is not doing what it's supposed to as done by this guide.

I tried this portforwarding both with the Upnp enabled and disabled from the POL settings, but both did not result in any difference in disconnections and FFXI-4001/2 errors. It's quite frustrating!

Ideally I'd like to know if that guide for portwarding is wrong (but I honestly don't believe it is), so that I don't have to use a DMZ. And I'd like to get both computers to not disconnect.

Yes. I did setup the static IP for each computer as described in the guide. This router is fairly new, and the one I used previously did not have the same problems. Which is another indication that the router is the problem. However it seems to me like there should be some configuration loophole for the router. I've seen many people with these same errors using different routers (mainly Linksys and some Belkin). If only I were more savvy with this stuff!