This works.
I was told by 'Square-Enix' that you need a Static IP on your PS2 with Port Forwarding enabled for the Ports listed on their website FFXI uses under the Platforms > Windows tab.
http://www.playonline.com/ff11us/envi/win/win01.html?pageID=win
The ports are:
TCP 25, 80, 110, 443 or 50000 - 65535,
UDP 50000 - 65535,
...and maybe UDP 53.
Here are a couple links to guide you through it.
http://boardsus.playstation.com/playstation/board/message?board.id=ffxi&message.id=231333
http://www.jlsnet.co.uk/index.php?page=cc_playstation2
This has additional information concerning the Network Adapter, if you need it.
http://www.dslreports.com/faq/onlinegaming/1._PS2_Network_Adaptor_-_Broadband
Edited, Mar 13th 2007 10:43pm by Pikko