This post is to help those who seem to be having some problems with some aspects of online play.

It should help those who cannot see games on the online board and possibly fix some of the in game voice chat that some experience.

What you need to know.
1] On your PS3 XMB,go to Network settings
2] Go to internet connection test and run it.

After it has run you will find at the very bottom something called NAT.
There are three types of NAT,funnily enough called NAT1,NAT2 and NAT3.

If you have NAT1 or NAT2 you probably won't be reading this post,as all should be working for you.
If on the other hand you have NAT3...well you have a problem.

You are behind a router/firewall. While your PS3 may be able to connect to the PSN and perform downloads/updates other functions may not work as intended.

That and another problem could be that your PS3 doesn't have a static ip address.

You can change your NAT3 to NAT2 and fix your router so that your PS3 has a static ip if you follow the instructions from the link below.which explains the process far better than I could.

http://www.ps3forums.com/showthread.php?t=74303

While I find the "how to" from this link a great help, it doesn't really explain in any great deal how to resolve static ip addresses problems,otherwise known as Port Forwarding.

So here is another link that not only explains what you are doing and how,also helps you get into your routers settings and change them.

http://portforward.com/

Hope this information helps.

Happy racing.