Re: Problems configuring /etc/network/interfaces

["Charles Bray" <charles@oshoville.com>]

----- Original Message -----
From: "Joey Hess" <joeyh@debian.org>
To: <debian-user@lists.debian.org>
Sent: Wednesday, October 24, 2001 9:57 AM
Subject: Re: Problems configuring /etc/network/interfaces


> Charles Bray wrote:
> > Strangely (to me), if I comment out the "auto lo" line in
> > /etc/network/interfaces and reboot, I can then successfully ping the
> > loopback address, indicating that the interface has been automatically
> > activated.  (So "auto lo" is evidently shutting it down.  I wish I could
> > find more thorough instructions for configuring
> > /etc/network/interfaces.)
>
> I hope you've read the interfaces(5) man page.

I've searched places like http://www.linuxdoc.org/docs.html#man, but I can't
find this man page.  My system doesn't know the command "man" yet, so I
can't type "man interfaces".

> This is a really strange problem you're having. You shouldn't need to
> add a route to the lo interface to be able to ping it. At least that's
> been the case as long as I can remember.

I see.  The lo interface must be up in order to ping it, but it doesn't have
to be manually added as a route.  This is what Lars Knudsen was telling me.
Experimentation shows that this interface is activated by the only line in
my /etc/network/interfaces file:

iface lo inet loopback

The "auto lo" remains commented out because of the "neighbor table overflow"
error.  I remain unclear about what the "auto" line is supposed to do that
the "iface" line doesn't do.  Maybe when I find the interfaces man page...

>What version of the kernel do you have?

Version 2.2.19pre17

> You can run the following command, which will bring up the lo interface
> the same way as it would if you hadn't commented out 'auto lo', and will
> also print out the commands it executes:
>
> root@silk:~>ifup -v lo
> Configuring interface lo=lo (inet)
> run-parts /etc/network/if-pre-up.d
> ifconfig lo 127.0.0.1 up
> run-parts /etc/network/if-up.d

ifup -v lo only produces the output:  ifconfig lo 127.0.0.1 up
....not very "verbose"

ifdown -v lo produces:  ifconfig lo down

> Presumably, if this messes up pinging loopback just as does 'auto lo',
> then one of those commands is the real culprit

Aside from not being verbose, these commands seem to work fine.

Thanks to everyone's help, my Debian system is now up and running.  For now,
it seems that the "auto lo" mystery isn't a major hinderance to me.  What's
bothering me now is the default gateway problem I mentioned in another post
(under the same heading as this one).

Thanks again,
Charles