How to get my ip address to work on my ps3?

I am trying to hook up on line, but all I have is one ethernet port in my modem so what I do is disconnect the ethernet from my modem to my tower and connect from my ps3 to my modem. I think I did all the settings right but it keeps coming up " IP...

address: failed" how do I get this thing to work?!!! I tried a wireless router but I kept losing connection. I am at wits end with this thing and am about to give up completely. I have had my cable guy come out and my phone guy come out and neither of them could help. could someone please help before I go insane!!!

* power off the modem and the ps3 for a few minutes.

* power on the modem 1st wait a few seconds then power on the ps3.

anytime you change the device connected to your modem you'll have to restart it.

Adding a router to your setup would fix this issue.

good luck

-thepope

its the same with me my connection to the wireless router is fine to be precise 97% and I've filled the settings in correctly but all of a sudden I turned my ps3 on and it tells me to go to settings network settings and when I do go on that I run a internet connection test and it keeps failing to obtain my ip adress I NEED HELP!!!