How do you determine if ethernet port(s) are bad in Ubuntu Linux?

Discussion in 'Networking & Security' started by scharfshutze009, Jun 20, 2017.

  1. scharfshutze009

    scharfshutze009 [H]ard|Gawd

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    Ok so I look this up and most guides tell what commands to use, but now what to actually look for that will help determine if the ethernet port is bad. Therefore, I did as follows, but how do I know my port or ethernet controller is bad because I can't ping my router or the other two computer on the network:


    hostname:~$ sudo -i ethtool enp6s0
    Settings for enp6s0:
    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: 10baseT/Half 10baseT/Full
    100baseT/Half 100baseT/Full
    1000baseT/Full
    Advertised pause frame use: No
    Advertised auto-negotiation: Yes
    Speed: Unknown!
    Duplex: Unknown! (255)
    Port: Twisted Pair
    PHYAD: 1
    Transceiver: internal
    Auto-negotiation: on
    MDI-X: Unknown (auto)
    Supports Wake-on: pumbg
    Wake-on: g
    Current message level: 0x00000007 (7)
    drv probe link
    Link detected: no
    hostname:~$ dmesg | grep enp6s0
    [ 20.308671] e1000e 0000:06:00.0 enp6s0: renamed from eth0
    hostname:~$ ^C
    hostname:~$

    I hope the ports aren't bad because there onboard, so if they are I'm going to need a new motherboard and that might be a problem because the board is 3 years old or almost 3 years old and I may not have much time to RMA if any.

    I should also say that I've configured static Ip addresses on the machine and on the router with dhcp reservations, but the machine can't get an IP from the router no matter what I do.
     
  2. Brian_B

    Brian_B [H]ard|Gawd

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    Easiest method I know of:

    Set static IP on your machine (don't rely on DHCP reservation for the moment)

    Try a different cable. Bad cables are surprisingly common.

    Try a different port on your switch/router.

    Try to ping a different device than your router on the LAN.

    Try to manually set the proper speed rather than rely on auto-negotiation

    If all that fails to resolve the issue, get a USB NIC and try that for temporary cheap solution.

    From what you have posted here - NIC isn't seeing a proper link, I would suspect cable first off, and work my way down from there.

     
  3. Perilous

    Perilous Gawd

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    bad cables are especially common when using PoE. @10% of the premade cables from monoprice fail for PoE.
     
  4. scharfshutze009

    scharfshutze009 [H]ard|Gawd

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    Thanks I tried another port, but that didn't work. I'm not sure a seven foot cable will reach instead of a 25 foot. My routers fine because the port works if I use it with my Wireless Access Point. Static IP's are already set in everything require and so is dhcp reservation. Speed is manually set in /etc/network/interfaces. The server is conneted to the interenet with a dual USB Ethernet adapter, so I guess that answers that question.
     
  5. scharfshutze009

    scharfshutze009 [H]ard|Gawd

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    Thanks Perilous, but it looks like its both ports or the controller because the server can connect with a dual gigabit eithernet adapter. I bought this cable from Office Max years ago and it's 25 foot belkin. You should remember I brought it to your house with my Asus G74 before I sold the G74 years later and if not it's ok. Now the question is what should I do about the bad ports. Should I try to RMA the motherboard.
     
    Last edited: Jun 21, 2017
  6. Perilous

    Perilous Gawd

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    Have you tried another cable? Copper cables can and will deteriorate over time.