How do I check if my network card has been detected and is working?

Question

Hello I am using Ubuntu 10, and am having problems with getting connected to wired internet. Normally when I connect a cable to my computer, the port would have a green and yellow light flashing. But now I only have the green on flashing once in a while. So I actually want to know if my network card has been detected.

eth0      Link encap:Ethernet  HWaddr 18:a9:05:22:cd:f9  
          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 (0.0 B)
          Interrupt:28 Base address:0xe000
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:4 errors:0 dropped:0 overruns:0 frame:0
          TX packets:4 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:240 (240.0 B)  TX bytes:240 (240.0 B)
wlan0     Link encap:Ethernet  HWaddr 00:26:82:3c:ac:27

          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 (0.0 B)
wmaster0  Link encap:UNSPEC  HWaddr 00-26-82-3C-AC-27-00-00-00-00-00-00-00-00-00-00

          UP RUNNING  MTU:0  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 (0.0 B)

This is what is displayed when I do ifconfig, but it isn't giving me any address.

Chris · Accepted Answer · 2010-08-27T15:28:49.773

Check if you can get out onto the net: ping google.com

If this fail's a few things could be happening.

As other's have said though, ifconfig will get you device details.

ifconfig

This should display something like:

eth0      Link encap:Ethernet  HWaddr AA:22:DD:CC:EE:FE
      inet addr:121.121.128.120  Bcast:128.146.128.255  Mask:255.255.255.0
      UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
      RX packets:28834210 errors:0 dropped:0 overruns:0 frame:0
      TX packets:34965403 errors:0 dropped:0 overruns:0 carrier:0
      collisions:0 txqueuelen:1000 
      RX bytes:17051041467 (15.8 GiB)  TX bytes:4435012315 (4.1 GiB)
      Memory:fc200000-fc220000 

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:6450 errors:0 dropped:0 overruns:0 frame:0
      TX packets:6450 errors:0 dropped:0 overruns:0 carrier:0
      collisions:0 txqueuelen:0 
      RX bytes:2266926 (2.1 MiB)  TX bytes:2266926 (2.1 MiB)

Notice how I have an inet addr defined. If you do not have an IP address then something is wrong.

If this is the case... most likely it would be a DHCP problem. Are you using network manager or anything to "manage" your network?

Can you ping 192.168.1.1 or ping 10.0.0.1? (Most likely your router's LAN ip is one of those)

If you can ping one of those, then you can see your router and you are not getting a IP from the router. This could be either your router DHCP not configured/setup or your system not requesting an IP from the router.

That is if you have a router.

Last thing to do:

ifdown eth0
ifup eth0

score 0 · Answer 2 · answered Aug 26 '10 at 18:14

0

Open a terminal window and type ifconfig. You should see an entry for eth0 which is your (first) hardwired Ethernet port. If it is working, (and DHCP is enabled) it should have an IP address assigned and you will see RX/TX packet activity.

answered Aug 26 '10 at 18:14

tcrosley

453

score 0 · Answer 3 · answered Aug 27 '10 at 18:57

If the failure immediately followed a re-install, the likely place to look is in the new installation's network setup. A quick test to confirm that would be to try connecting to a known-working router, and try connecting to your switch from another, known-working computer. Either of those tests whether the failure in your OS or upstream of it.

score 0 · Answer 4 · answered Aug 30 '10 at 17:20

Your question is a little unclear, but you can check to see if your hardware has been detected with the command "lspci". If is isn't already installed, its available in the "pciutils" package.

If you see something like this:

00:12.0 Ethernet controller: VIA Technologies, Inc. VT6102 [Rhine-II] (rev 7c)

Then your hardware has been detected.

The check for link detection, I use ethtool.

root@pro-38-gl:/home/albertlash# ethtool eth0
Settings for eth0:
Supported ports: [ TP MII ]
Supported link modes:   10baseT/Half 10baseT/Full 
                        100baseT/Half 100baseT/Full 
Supports auto-negotiation: Yes
Advertised link modes:  10baseT/Half 10baseT/Full 
                        100baseT/Half 100baseT/Full 
Advertised auto-negotiation: Yes
Speed: 100Mb/s
Duplex: Full
Port: MII
PHYAD: 1
Transceiver: internal
Auto-negotiation: on
Supports Wake-on: pumbg
Wake-on: d
Current message level: 0x00000001 (1)
Link detected: yes

Though mii-tool will work as well.

How do I check if my network card has been detected and is working?

4 Answers4