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Thread: 12.10 "Destination Host Unreachable" between two computers connected by ethern

  1. #1
    Join Date
    Apr 2013
    Beans
    4

    12.10 "Destination Host Unreachable" between two computers connected by ethern

    Hello,

    I realize I'm doing something many people have done before, so I'm sorry for revisiting such an simple problem!

    I'm trying to connect to desktops running Ubuntu 12.10 (one with ubuntu desktop, and one with ubuntu server, for what it's worth) using an ethernet cable, no router or hub, via pci NICs with auto-MDIX (no crossover cable needed).

    My /etc/network/interfaces on server one includes:
    Code:
    auto eth0 
    iface eth0 inet static
    address 192.168.0.1
    netmask 255.255.255.0

    And on server two includes:
    Code:
    auto eth0 
    iface eth0 inet static
    address 192.168.0.2
    netmask 255.255.255.0

    On both computers, ifconfig show eth0 with the correct addresses, but when I try to ping one computer from the other, I get "Destination Host Unreachable".

    The output of route on server one includes the following lines (related to eth0):
    Code:
    Kernel IP routing table
    Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
    link-local      *               255.255.0.0     U     1000   0        0 eth0
    192.168.0.0     *               255.255.255.0   U     0      0        0 eth0
    And the output of route on server two includes the following lines (related to eth0):
    Code:
    Kernel IP routing table
    Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
    192.168.0.0     *               255.255.255.0   U     0      0        0 eth0
    (eth1 is connected to the external internet, and works on both computers)

    Anyone have any leads on what might being going wrong? Is there something obvious I'm missing?

  2. #2
    Join Date
    Jan 2006
    Location
    Not heaven... Iowa
    Beans
    Hidden!
    Distro
    Ubuntu

    Re: 12.10 "Destination Host Unreachable" between two computers connected by ethern

    I'd be inclined to try a crossover cable or hub/switch - just to see if it might be an auto-MDIX problem. I presume you have verified that the cable works properly.
    Linux User #415691 Ubuntu User #8629
    Iowa Team (LoCo): [Wiki] [Launchpad]
    IRC channel: #ubuntu-us-ia on irc.freenode.net

  3. #3
    Join Date
    Mar 2007
    Beans
    301
    Distro
    Ubuntu 6.10 Edgy

    Re: 12.10 "Destination Host Unreachable" between two computers connected by ethern

    Firewall?

  4. #4
    Join Date
    Apr 2013
    Beans
    4

    Re: 12.10 "Destination Host Unreachable" between two computers connected by ethern

    thanks for the suggestions!

    Any chance you could give some pointers as to identifying or disabling firewalls? Is that something in the ubuntu operating system? (I'm pretty new to networking.)

    And I'll check the cable tomorrow morning -- I'd be surprised, although happy, if it was just the cable.

  5. #5
    Join Date
    Apr 2013
    Beans
    4

    Re: 12.10 "Destination Host Unreachable" between two computers connected by ethern

    It was not the cable -- I tried using a cross over cable as well.

    Mystery remains open.

  6. #6
    Join Date
    Apr 2012
    Beans
    7,004

    Re: 12.10 "Destination Host Unreachable" between two computers connected by ethern

    Quote Originally Posted by nusstorte View Post
    The output of route on server one includes the following lines (related to eth0):
    Code:
    Kernel IP routing table
    Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
    link-local      *               255.255.0.0     U     1000   0        0 eth0
    192.168.0.0     *               255.255.255.0   U     0      0        0 eth0
    And the output of route on server two includes the following lines (related to eth0):
    Code:
    Kernel IP routing table
    Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
    192.168.0.0     *               255.255.255.0   U     0      0        0 eth0
    (eth1 is connected to the external internet, and works on both computers)

    Anyone have any leads on what might being going wrong? Is there something obvious I'm missing?
    Does it work if you take down eth1? May we see the entire routing table(s)?

  7. #7
    Join Date
    Apr 2013
    Beans
    4

    Re: 12.10 "Destination Host Unreachable" between two computers connected by ethern

    The problem remains a mystery, but I've narrowed it down:

    I was using two offboard nics (D-Link adapters, model no. DGE-530T). It turns out the configuration I originally asked about was completely correct, and works without fuss if I use it to connect the on board nics. After a bit more messing around I've learned both D-Link adapters do not work in one of the machines I've set up (they both work in the other box fine).

    By do not work, I mean the following: The machine recognizes the ethernet interface, and configures it, but appears to be incapable of sending or receiving packets. tcp dump shows nothing, and when connecting the nic to a router, dhclient fails.

    It can't be the software, because both machines have a fresh install of ubuntu 12.10. The box I'm using is Lenovo Thinkcenter M82. So... is this a really strange hardware compatibility problem? Is there a ghost in the machine ;D ?

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