Ubuntu 10 and 11.04 issue connecting to internet via Ethernet

To elaborate a bit, hardware light is on the back of the box. Modem is working fine and I have an airport extreme that I can reconnect to the modem and have access to the internet like normal on all my other devices.

Also tried multiple ethernet cords with the same result.

Hi Jonas,

Did you already setup the IP address of your ethernet?
Is your modem running DHCP Server?
Would you mind give me the output of this command from your terminal program (Application > Accessories > Terminal or press ALT+F2 then type "gnome-terminal" without quotes)?
ifconfig -a ; cat /etc/network/interfaces

Copy all the output then paste here. When you run that command, make sure that ethernet cable is plugged in to modem.
Looking forward for your information...

-Luky-

Its easier to type the message via my iphone on 3g network than to copy paste from machine that has no network so here goes:

auto lo
iface lo inet loopback

eth0    Link encap:Ethernet  HWaddr 00:13:20:1f:be:7e
            UP BROADCAST MULTICAST MTU:1500 Metric:1
            RX packets:0 errors:0 dropped:0 overruns:0 frame:0
            TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
            collisions:0 txqueuelen:1000
            RX bytes:0 (0.0 B)  TX bytes: (0.0 B)

eth1    Link encap:Ethernet HWaddr 00:14:bf:5e:82:46
            inet6 addr: fe80::214:bfff:fe5e:8246/64 Scope:Link
            UP BROADCAST MULTICAST MTU:1500 Metric:1
            RX packets:0 errors:0 dropped:0 overruns:0 frame:0
            TX packets:0 errors:12 dropped:0 overruns:0 carrier:24
            collisions:0 txqueuelen:1000
            RX bytes:0 (0.0 B)  TX bytes: (0.0 B)
            Interrupt:22 Base address:0x1000

lo         Link encap:Local Loopback
            inet addr:127.0.0.1 Mask:255.0.0.0
            inet6 addr:  ::1/128 Scope:Host
            UP LOOPBACK RUNNING MTU:16436 Metric:1
            RX packets:104 errors:0 dropped:0 overruns:0 frame:0
            TX packets:104 errors:12 dropped:0 overruns:0 carrier:24
            collisions:0 txqueuelen:0
            RX bytes:8064 (8.0 KB)  TX bytes:8064 (8.0 KB)

auto lo
iface lo inet loopback

Here's what I get after connecting directly to the modem, bypassing the router.

auto lo
iface lo inet loopback

eth0    Link encap:Ethernet  HWaddr 00:13:20:1f:be:7e
            inet6 addr: fe80::213:20ff:fe1f:be7e/64 Scope:Link
            UP BROADCAST MULTICAST MTU:1500 Metric:1
            RX packets:42976 errors:0 dropped:0 overruns:0 frame:0
            TX packets:29 errors:0 dropped:0 overruns:0 carrier:0
            collisions:0 txqueuelen:1000
            RX bytes:2626752 (2.6 MB)  TX bytes:7056 (7.0 KB)

eth1    Link encap:Ethernet HWaddr 00:14:bf:5e:82:46
            inet6 addr: fe80::214:bfff:fe5e:8246/64 Scope:Link
            UP BROADCAST MULTICAST MTU:1500 Metric:1
            RX packets:0 errors:0 dropped:0 overruns:0 frame:0
            TX packets:0 errors:12 dropped:0 overruns:0 carrier:24
            collisions:0 txqueuelen:1000
            RX bytes:0 (0.0 B)  TX bytes: (0.0 B)
            Interrupt:22 Base address:0x1000

auto lo
iface lo inet loopback

lo         Link encap:Local Loopback
            inet addr:127.0.0.1 Mask:255.0.0.0
            inet6 addr:  ::1/128 Scope:Host
            UP LOOPBACK RUNNING MTU:16436 Metric:1
            RX packets:216 errors:0 dropped:0 overruns:0 frame:0
            TX packets:216 errors:0 dropped:0 overruns:0 carrier:0
            collisions:0 txqueuelen:0
            RX bytes:16896 (16.8 KB)  TX bytes:16896 (16.8 KB)

auto lo
iface lo inet loopback

Are you using ipv6 on your network, Jonas?

oh is that what inet6 is? i'm using ipv4 on other windows computers.

One of the ethernet ports is working while the other isn't. This is a computer that was given to me so i don't know what works and what doesn't. The port that works is actually a pci card which kinda leads me to believe that it is a replacement for faulty default hardware. Does this seem logical? I forgot there was another port on the thing until I did the test you prescribed so thanks!

I guess the issue is resolved.
Thanks for the help.