Since the the games own servers have shutdown here is a good third-party server. its by a guy called Snipe.
To use his servers is quite simple. Follow these directions to use servers -
[HOW TO GET ONLINE]
THPS4 / THUG
On THPS4 and THUG, you can simply go into the manual settings and turn off Auto-Obtain DNS Servers? and put in the IP, as in these instructions:
On the main menu go to Options
Click Network Options
Click on Settings
Click on Connection Settings
Turn Auto-Obtain DNS Servers? Off
set: Primary DNS IP to: 66.232.112.179 and
Secondary IP to: 208.67.222.222
Now you will run off snipes servers and can now get back on all of your THPS games.
THUG2 / THAW You can use almost any online game (the Tony Hawk games do not have this feature) to make this network configuration. Go to the online section of the game and then look for a button that says, "Create/Edit Network Configuration". Click that and then follow the instructions on screen. From there you should be able to create the network configuration.
When asked if you would like to set the DNS server address automatically,
Select Manual.
Under Primary DNS Address put this in: 66.232.112.179 If you do not have a Secondary DNS Address from your ISP, put this in: 208.67.222.222 Note: If you have configured your PlayStation 2 with a static IP address, when asked if you would like to set the IP address automatically, select "Manual" and enter your static IP network configuration.
Note: You can also set this network configuration into your PlayStation 2 with the Network Start-Up Disc, by selecting "Manual Settings", as in the pictures.
Creating New Network Configuration Profile/Power Cycle If you are having trouble connecting to the master server or authenticating DNAS, try deleting your PlayStation 2's network configuration and then creating a new network configuration profile. There are a few different things you may want to try to establish a connection:
Turn off your cable modem, any network equipment (such as a router), and your PlayStation 2 system and unplug the power cables from the electrical outlet for a minimum of 2 minutes.
While your system is turned off and unplugged, check all cables for damage, and make sure they are plugged in securely.
Turn on the modem, router (if you have one), PlayStation 2, etc., starting at the cable modem and working back toward the PlayStation 2 system.
Using a Network Start-Up Disc or online enabled game, create a new network configuration profile.
Direct Connecting If you are having trouble connecting to the master server, authenticating DNAS, or hosting a game online, try to connect directly from the modem to the ethernet port on your PlayStation 2 system or network adaptor.
this tutorial is made using info taken form following websites.
thlive.net,thps.it.cx
PLEASE come ONLINE on THPS 4! I AM ALONE IN WHOLE WORLD!! TO BE PLAYING IT!!