[PLUG] Network is unreachable

[Rich Shepard]

On Sat, 25 Dec 2004, Richard Steffens wrote:

> Once power was restored, the machines came back up. But, the linux machine 
> won't talk to the network. When I try to ping another machine in the house I 
> get the message, "Network is unreachable".

> When I run ifconfig, I only see information about lo; nothing about eth0.
>
> When I run ifconfig eth0, I see its MAC address and a few lines of 
> information. I assume that tells me that the ethernet card is present and 
> will talk to the OS.

> So, where do I go from here?

   Two steps to the left, down one.

   I've seen this before. The network did not come up fully on one or both
machines.

   On the one showing only lo, try
ifconfig eth0 (down/stop) #depends on your distribution
   then
ifconfig eth0 (up/start) #ditto

   Now, when you do 'ifconfig -a' you should see a line like this:

eth0      Link encap:Ethernet  HWaddr 00:50:22:E1:1D:CF
           inet addr:192.168.55.1  Bcast:192.168.55.255  Mask:255.255.255.0
           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
                        ^^^^^^^

   The "RUNNING" is what you want to see.

   Then restart the network on both machines:

   /etc/rc.d/sysconfig/network restart (IIRC from Red Hat days with
SysV-style init scrips) or
   /etc/rc.d/rc.inet1 restart (for those distributions with BSD-style init
scripts).

   Then try pinging one machine from the other (both by name and IP address).

   If that doesn't do the trick, let us know what 'ifconfig -a' shows on both
machines.

HTH,

Rich