I have a linksys router and I noticed lots of connection problems for a while when I first started playing FF11. I upgraded the firmware because I hadn't done that in a while. In the first week I think my router crapped out once. Then I'd say in about the last month it did it once again, then again I think it was my ISP downing their networks without telling anyone, as usual. So umm, moral of the story is keep your firmware up to date on your router.
Also, on most routers they have something called "DMZ host". If you put the IP of your computer in there, it will forward all ports to your computer, effectively placing you outside of the network, on the internet side. It's a little more dangerous than static forwarding because none of the ports will be blocked by the router, but I was finding with all the forwarding I was having to do for games etc. it was becoming a major pain in the rear end.
Edited, Thu Jan 29 16:17:59 2004 by heavymettle