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Old 11-23-2007, 07:21 AM   #1
humbletech99
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Registered: Jun 2005
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eth1 not detecting link, despite NIC link light


I have a linux firewall which has a network card, eth1 that insists the link is down, despite having a link light on the card itself. I have used ethtool to check and the result is as follows:
Code:
# ./ethtool eth1
Settings for eth1:
        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: 10Mb/s
        Duplex: Half
        Port: MII
        PHYAD: 1
        Transceiver: internal
        Auto-negotiation: on
        Current message level: 0x000020c1 (8385)
        Link detected: no
There is a statically assigned ip address and the cable is definitely plugged into the NIC and the other end into the switch. There is even data activity light blinking, but linux still doesn't see the link.
Code:
# ifconfig eth1
eth1      Link encap:Ethernet  HWaddr xx:xx:xx:xx:xx:xx
          inet addr:x.x.x.x  Bcast:x.x.x.x  Mask:x.x.x.x
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:867 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:0 (0.0 b)  TX bytes:36414 (35.5 Kb)
          Interrupt:4
So the link does not appear up, despite what the hardware says. The kernel definitely detects the card, otherwise there would be no eth1. I can ping the eth1 ip address from the box itself but not from anywhere else on the network, and nor can the box ping anything anywhere else.

It looks like it is not receiving any packets at all. I have changed switch ports, the cable, and used a second switch. Both switches have other devices working on them.

I have changed network cards, pci slots, rebooted several times etc.

This was working fine with the original network card and the ip address up until yesterday when there was a power failure and the machine went down hard. I am leaning towards broken hardware, but I've changed the NIC, the switch, the cable and used different pci slots. There is another network card in the box which still works... but I need two interfaces since it's a firewall.


I am truly stuck. Any ideas?
 
Old 11-23-2007, 07:38 AM   #2
jschiwal
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Is this card the same model? You may need to run your distro's network devices setup, deleting the old entry and adding a new one for this device. You may be using the wrong kernel module.

Also, look at the output of dmesg, and scan your /var/log/messages logfile.
 
Old 11-23-2007, 08:07 AM   #3
humbletech99
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it was auto detected otherwise there wouldn't be any eth1.
 
Old 11-23-2007, 10:19 AM   #4
armandrix
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Hi humbletech99

It's realy strange....

I had once a problem like this with slackware, and the conclusion wasn't cool..

well, let's see it :

1- eth1 Link encap:Ethernet HWaddr xx:xx:xx:xx:xx:xx
inet addr:x.x.x.x Bcast:x.x.x.x Mask:x.x.x.x
UP BROADCAST MULTICAST MTU:1500 Metric:1

** your system had recognized the nic and bring it up and running (I understand that x.x.x.x means you have an ip address, mask, etc like 192.168.0.10).

2- RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:867 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 b) TX bytes:36414 (35.5 Kb)

** Your interface eth1 has sent packages with sizes over the network (or think so) but receive none.

3- You said that you have an firewall up and running, and I'm thinking that you're sure the interface eth1 is well configured into the firewall rules. Please check it carefully.

- Based on this, I can ask you one more check. To verify if this nick works in another machine, cause when I had an alike trouble, the nic had been damaged without alternatives except trash. And note that it still blinking the leds and the system had seen no failures with it. Just don't works like yours.

- You also said that you can ping it from other card in the same machine. So please check it and "after pinging" (and of course getting responses), check the ifconfig output saying "RX bytes or RX packets" greater than 0.
As you leave pinging running these numbers must get increased.

good luck
 
Old 11-24-2007, 09:44 PM   #5
jschiwal
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You still should look at the output of "sudo /sbin/lspci -v" and use that information to determine if the correct kernel module is being used.

Deleting the interface in the configuration and then starting over and adding it again might fix an incorrect hardware reference or modprobe.conf entry. Your system may be reading the old ifcfg-eth1 file and using that. That could be why eth1 is showing up.

Please put your distro in your profile or indicate the distro you are using. For example, if it were SuSE, then in the devices network setup, there is a field in the configuration indicating the kernel module used.

Also, check your logs. There may be kernel module messages indicating what the problem is.

The link light on an interface might be powered by the ethernet cable. I've seen them light even when the computer is powered of.
 
Old 08-19-2014, 07:41 AM   #6
krankes-kind
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reload the kernel drivers

I know, the thread is dead old, but it would have helped me so here we go:

Solved the exact same issue only by reloading the kernel drivers:
First find the driver for your interface:
Code:
# ethtool -i em1
driver: atl1c
version: 1.0.1.1-NAPI
firmware-version: 
bus-info: 0000:01:00.0
supports-statistics: no
supports-test: no
supports-eeprom-access: yes
supports-register-dump: yes
supports-priv-flags: no
Then remove the driver and add it again
Code:
# modprobe atl1c -r
# modprobe atl1c
Check if it did the trick
Code:
# ethtool em1
Settings for em1:
	Supported ports: [ TP ]
	Supported link modes:   10baseT/Half 10baseT/Full 
	                        100baseT/Half 100baseT/Full 
	                        1000baseT/Full 
	Supported pause frame use: No
	Supports auto-negotiation: Yes
	Advertised link modes:  Not reported
	Advertised pause frame use: No
	Advertised auto-negotiation: Yes
	Speed: 100Mb/s
	Duplex: Full
	Port: Twisted Pair
	PHYAD: 0
	Transceiver: internal
	Auto-negotiation: on
	MDI-X: Unknown
	Supports Wake-on: pg
	Wake-on: d
	Current message level: 0x0000003f (63)
			       drv probe link timer ifdown ifup
	Link detected: yes
 
Old 08-19-2014, 03:06 PM   #7
jefro
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I might be tempted to build a loopback connector and see what it does.
 
  


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