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Re: New User- Network Problem



On Thu, Feb 14, 2008 at 09:14:53AM -0500, Paul Cartwright wrote:
> On Thu February 14 2008, Douglas A. Tutty wrote:
 
> I have a similar problem. I am running Debian Etch:
> # uname -a
> Linux paulandcilla 2.6.18-6-686 #1 SMP Sun Feb 10 22:11:31 UTC 2008 i686 
> GNU/Linux
> 
> 
> with the latest updates. Now ( as I recently found out) when I reboot after.. 
> kernel update, whatever update/problem, my network doesn't come back up. I 
> issue the command line ifdown eth0, ifup eth0 and it comes back up. I can't 
> remember exactly, but ifconfig ( before the network is working) shows either 
> just lo, or eth0 has the 169 address.
> How would I troubleshoot that? If I am not home, and the power goes out, when 
> the system comes back up, my wife would not be able to get the network 
> working...

OK, initscripts; something to work on step by step.

Here's what I'm hearing.

1. 	Power off
2.	Power on
3.	Boot progresses, init runs
4.	system comes up but network doesn't come up
5.	ifdown eth0 && ifup eth0 brings the network back up

6?	But then all those initscripts that come after netoworking may
	be messed up.


Questions:

Does lo come up; is it just eth0?

What happens if instead of ifdown eth0 && ifup eth0, you do
	# /etc/init.d/networking restart

	?

Is there anything in /var/log/boot or /var/log/syslog from the boot
period that gives any error info?

Boot with the kernel command line init=/bin/sh
you'll get a shell prompt after the kernel boots, / will be ro

cd /etc/rcS.d
ls

now, manually, for each script that starts with S, run it with the
parameter "start".  After each, run /sbin/ifconfig and see what is up.

What happens after the networking initscript is started?  What error
messages are there?

Once you have these error messages, you'll have somewhere to go.  Note
that after / is mounted rw, you can use script or something to record
the output. Of course, a serial console is even better, logged from
another box.

If after networking, you don't have eth0, then after each successive
initscript, after verifying that there is not networking, restart the
networking initscript.

My guess is that in your particular installation, there is a conflict of
boot dependancies, e.g. networking can't start until a module is loaded
but that happens in a later init script.  This manual booting procedure
will track this down.  Then you can make a temporary fix (even if its
adding a symlink to start networking again at a later point in the
boot), and report the bug.

Good luck.

Doug.


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