[PLUG] Testing Wired Network Connectivity

Mike C. mconnors1 at gmail.com
Sun Dec 2 23:01:06 UTC 2012


On Sun, Dec 2, 2012 at 2:48 PM, Mike C. <mconnors1 at gmail.com> wrote:

>
>
> On Sun, Dec 2, 2012 at 2:46 PM, Mike C. <mconnors1 at gmail.com> wrote:
>
>>  On Dec 1, 2012, at 12:09 PM, Mike C. <mconnors1 at gmail.com> wrote:
>>
>>>
>>> > 1. Run the command  "ping 127.0.0.1" from the command line while not
>>> > connected to any networks. This will test the NIC, the NIC drivers and
>>> the
>>> > tcp/.ip stack.
>>>
>>> Are you sure about that? I was under the impression that no NIC is
>>> required to have a loopback (127.x.x.x) network interface. It's a software
>>> only interface. The only thing that will test is the tcp/ip stack.
>>>
>>> Russell Johnson
>>> russ at dimstar.net
>>
>>
>> No, I'm not. I can find a definitive answer nor can I confirm nor deny
>> with my own testing. When I stopped the networking sevice, only the lo
>> interface was visible with ifconfig and it responded with a ping. When I
>> unloaded the NIC drive via modprobe -r, both eth0 and lo were visible via
>> ifconfig and lo responded to a ping.
>>
>> So, I'll restate my testing procedure.
>>
>> 1. Run the command "lspci | grep Network" to verify the Ethernet
>> controller is seen by the pci bus and get info on it.
>>
>> lspci | grep Network
>> 00:19.0 Ethernet controller: Intel Corporation 82566MM Gigabit Network
>> Connection (rev 03)
>>
>> 2. Verify driver info
>>
>

> dmesg | grep Network
>> [    1.304272] e1000e: Intel(R) PRO/1000 Network Driver - 1.5.1-k
>> [    1.618525] e1000e 0000:00:19.0: eth0: Intel(R) PRO/1000 Network
>> Connection
>>
>>
> 3, Verify NIC hardware is functioning

dmesg | grep e1000e
[    1.304272] e1000e: Intel(R) PRO/1000 Network Driver - 1.5.1-k
[    1.304275] e1000e: Copyright(c) 1999 - 2011 Intel Corporation.
[    1.304310] e1000e 0000:00:19.0: PCI INT A -> GSI 20 (level, low) -> IRQ
20
[    1.304324] e1000e 0000:00:19.0: setting latency timer to 64
[    1.304462] e1000e 0000:00:19.0: irq 45 for MSI/MSI-X
[    1.618521] e1000e 0000:00:19.0: eth0: (PCI Express:2.5GT/s:Width x1)
00:1c:25:18:3c:78
[    1.618525] e1000e 0000:00:19.0: eth0: Intel(R) PRO/1000 Network
Connection
[    1.618554] e1000e 0000:00:19.0: eth0: MAC: 6, PHY: 6, PBA No: 1008FF-0FF
[   19.984262] e1000e 0000:00:19.0: irq 45 for MSI/MSI-X
[   20.040152] e1000e 0000:00:19.0: irq 45 for MSI/MSI-X
[ 1348.132595] e1000e 0000:00:19.0: irq 45 for MSI/MSI-X
[ 1348.188244] e1000e 0000:00:19.0: irq 45 for MSI/MSI-X

4. At this point eth0 should be up and visible when you run the ifconfig
command and the interface should be ip addressable either manually or via
dhcp.

5. At this point a ping test is mostly trivial. If it fails, you can be
confident that it's not a NIC hardware or driver issue, but an ip network
config issue to include DHCP issues.



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