Re: Bizarre one-way network disconnection

From: Kevin Buhr (buhr_at_telus.net)
Date: 08/30/03

  • Next message: Paul Burkett: "IMAP with virtual users" 
    To: Mark Roach <mrroach@okmaybe.com>
Date: 29 Aug 2003 17:42:46 -0700

    Mark Roach <mrroach@okmaybe.com> writes:
    >
    > All of a sudden, the server will reject all network communication on
    > eth0, won't respond to pings, no ssh, no samba. (ssh gives the message :
    > No route to host) However, if I ssh in through eth1 I am able to ping
    > addresses _from_ eth0. If I ifdown eth0 && ifup eth0 everything starts
    > working again.

    Sounds a little like it's not responding to ARPs on the "eth0" side.
    Machines that don't already know "eth0"'s MAC address can't send
    packets to it until it responds to an ARP request, but it's not a
    problem when pinging out, for example, because the target host (or the
    router) remembers the IP->MAC mapping when it receives the request
    packet and knows where to deliver the reply on that basis.

    Running "tcpdump" on both the misbehaving host and another host while
    trying to (unsuccessfully) ping in to the misbehaving host would
    certainly help show what's going on.

    > The only strange thing that I noticed is that each time this has
    > happened, when I do a "ps ax" the process listing pauses midway, and
    > hangs for a few seconds before displaying the next process (an smbd
    > process) there is nothing in the syslog, ifconfig doesn't show any
    > errors on the interface

    Is this on the console? Or over an SSH connection? 

    -- 
Kevin <buhr@telus.net>
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