User new to Ubuntu with Networking Problems

[ctm54]

Hey guys. Let me preface this by telling you where I'm at in general. The machine I'm having trouble with is my first computer build, and this is my first foray into Ubuntu. I'm at a power user level on Mac, so I sort of understand syntax and a few basic commands in Unix. But when I've looked at other threads for similar problems, the discussion has been a tiny bit over my head. So forgive me if I have to ask for clarification on what you say. With all of that out of the way...

The short version is I can't connect to the internet via ethernet cable.

The cable is plugged in to the ethernet port on my motherboard. When I tell Ubuntu to connect automatically with DHCP, it spins for a while and then fails to connect. When I give it a manual address (and set up the appropriate routing instructions on my router) it says it's connected, but I cannot access the internet or even ping the router.

Since this is my first computer build, I'm not ruling out that it's a hardware or driver issue, but it seems unlikely since the OS clearly recognizes that there is an ethernet port.

Here's what I'm working with:

-ASROCK N68C-GS FX Motherboard (connecting the router directly to the ethernet port on the motherboard)
-Ubuntu Desktop 12.04 LTS
-Asus RT-N12 router

Any guidance would be greatly appreciated. Thanks!

[snip3r8]

First off you will not be able to connect to the internet though your router with a static ip so that option is out . maybe try creating a new connection by clicking the networking icon in the top right corner of the screen and selecting edit connections, from here you should be able to create a new DHCP connection.

[Lars Noodén]

The wired networking has always been something that has worked out of the box for me. What happens when you try to manually get a DHCP lease?

sudo dhclient eth0

[ctm54]

snip3r8 - when I try to connect automatically with DHCP the connection icon spins for a while and then fails to connect.

Lars - when I enter that code in terminal, I get the same results as above.

Also, why won't I be able to connect with a static IP? I'm planning on using this machine as a media server so I static IP would be ideal.

[coffeecat]

Thread moved to Networking & Wireless.

@ctm54, I've moved your thread from the Apple subforum because that is for people running Ubuntu on Apple hardware. I've also removed the "Mac" from the thread title since your problem is not with a Mac.

[Cheesehead]

Paste the result of the following commands here:

dmesg | grep eth
ifconfig -a eth

[steeldriver]

... also this one please

lspci -vnn | grep -A2 -e "\[0200\]" -e "\[0280\]"

[ctm54]

Cheesehead - results of the gmesg one are:

http://pastebin.com/867Zh7Fj

results of the ifconfig are:

http://pastebin.com/uKNsTFVH

steeldriver - when I entered the command you suggested terminal just returned another entry line and didn't print anything out.

[Cheesehead]

What kernel are you running?
The command uname -r will tell you. Please paste the result here.

I ask because this seems very much like a bug in the forcedeth module back from 2007-2008, long since fixed. If you happen to be running a 2.6.2x kernel, an upgrade would be the first thing to try.

If you're running a current 3.x.x version kernel, then it's probably not that long-fixed bug. I know this sounds silly, but I recomment testing your hardware - the cable and both NIC ports. While you may indeed have discoved a regression bug, it's more likely that you're trying to communicate through a bad cable or port.

[ctm54]

3.2.0-23-generic-pae

According to my limited research that's consistent with my running 12.04.

For testing, I'm gonna plug the same cable from the same port on my router into my MBP and see if I can connect that way. If that works, is it safe to assume the ethernet port on my motherboard is no good. Should I exchange it for another one or should I just buy another PCI ethernet card.