Re: Problems configuring /etc/network/interfaces
On Wed, Oct 24, 2001 at 02:36:44PM -0700, Charles Bray wrote:
| ----- 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".
apt-get install man-db
| > 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:
Right.
| 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...
I saw something really strange once, and I have no idea how it
happened. I was getting errors about the syntax in my interfaces
file, and commenting out the "auto" line corrected it. When I reread
the manpage I saw that there was a "noauto" option for the iface
stanzas which would prevent the interface from being brought up
automatically at boot time. So I changed it and figured it was a new
format. After some upgrade (it is weird because I started with potato
and went straight to woody) I got complaints about the "noauto" option
in my iface stanza. I looked through the manpage and found that that
option was gone, but the "auto <name>" line was back.
The auto option is supposed to bring up the interface at boot time.
This is useful for loopback, static interfaces, and dynamic interfaces
where a link-layer connection is guaranteed at boot time.
(non-laptops and non-ppp interfaces).
| >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
Not very verbose, but that is exactly what the ifup/ifdown command
did. See the 'ifconfig' command for a lower level interface and more
control. You will surely see more information for an ethernet
interface or one that uses dhcp.
You can use 'ifconfig' to see all the currently configured interfaces.
'ifconfig <name>' will show just '<name>'.
HTH,
-D
Reply to: