I did played GT4 online by the x-link.
http://www.teamxlink.co.uk/?go=quickstart
Some while ago I wrote a small desription how to start.
You will need:
-1 ethernet cable
-PS2slim or the old one but then you will need an adapter which can placed in the back of the PS2.
-Router
-Also make sure the fire wall will regornise the x-link or else just shut it down.
First register at the X-link and download the x-link kai evolution 7
:Go to all programs on your pc.
-klik on xlink kai evolution 7
you'll see
-start kai
-start kai configuration tool
klik on start kai conf. tool
Go to
-UI------->default
-networkadapter------------>auto detect and lock
-default xtag------------>your username
-default password------------->your pass
- V for auto connection
-chose engine after----------->loss of UI
-accept UI connections from------------->any IP address
This is done.
Now the PS2
-Go to options
-go to Lan connection
put autoconnection on NO
-go to lan play
Machine name:Take your name(when you race your name will appear to other racers)
Host-No
style-play
no. of players-(your no host so doesn't matter)
replay target-(mine says player 1,I think not important)
No. of monitors-0
monitor position-centre
monitor type-normal
network traffic-light
SAVE
Go to multilan race
If yo press "create new network configuration"you'll see-->
-hardware sce\ethernet
-operation mode--->autodetect
(Perhaps the machine will ask if you want to make a new newwork,press OK)
Press OK
name-what ever,it is just important you fill something in.
authentication-NO
user ID-nothing
password-nothing
use DHCP-yes
ip address-all 0
netmask-all 0
default router-all 0
use auto DNS-yes
primary DNS-all 0
secondary DNS-all 0
press Ok---->auto saving
Set up the hardware;
Connect your router with the ethernetcable to the PS2.
-Go to programs on your pc and press x-link kai evo 7,select start Kai.
-You will see a half image,look at the right in the midle and select the little arrow.The image will full screen now.
-Then select the small globe pic on top of the page.
-select Playstation 2
-select GT4
-select the "Glass that makes large"
-Go to your playstation>multilanrace>connect
If all went well a line will show with "your playstation has been succesfully configured" on your pc screen.
Now it is possible to race others in your region.
(NTSC USA,Europe Pal,Aus Pal)
Distance between racers will influence the "ping",the lower the better.
Advice :take the time to find things out.
Also this link can help
https://www.gtplanet.net/forum/showthread.php?t=65171 but can make things very confused.