no auto for network interface?

Zach uid000 at
Thu Nov 17 15:31:24 UTC 2005

Thanks for the information, this is very instructive.  It may take me
a bit to grok all this but, it's good to have an explantion of what
these stanzas do.

On 11/17/05, Derek Broughton <news at> wrote:
> Zach wrote:
> > actually, ifplugd is not installed.  The reason the interface isn't
> > configured if the cable isn't plugged in is because it's setup to use
> > dhcp:
> > iface eth0 inet dhcp
> > So no cable, no dhcp, no configuration.
> Right, of course.
> >
> > As far as wireless not working with auto, why not? it's got everything
> > it needs.
> I didn't think your wireless interface _could_ have everything it needs at
> "auto" time.  I guess I was wrong :-(
> > What is confusing however is why eth0 works even without auto?
> >
> > can anyone demystify the hotplug lines?
> >
> > What does this mean:
> > mapping hotplug
> mapping xxx
> means, when an interface is brought up using "ifup iface=xxx" that mapping
> stanza is used.  Hotplug automatically tries to bring up the interfaces it
> controls using "ifup iface=hotplug"
> > script grep
> The script specified in the mapping stanza is executed with the name of the
> interface as the first parameter and then the following "map" lines are
> passed on stdin to the script, with the "map" stripped.  In this case,
> then, it executes:
>   grep eth0
>   eth1
> which returns a null string and nothing will happen. When the wireless iface
> is brought up, hotplug will execute "ifup eth1=hotplug" and the hotplug
> mapping will execute:
>   grep eth1
>   eth1
> and return "eth1" - this makes ifup retry with the "eth1" stanza.  So I'm
> still not really convinced that it comes up because of the "auto" - but
> either auto or hotplug brings it up.
> I still see no good reason, since ifplugd _isn't_ present, for your eth0 to
> be coming up. Try blacklisting the eth0 driver module
> in /etc/hotplug/blacklist.  I'm _pretty_ sure "ifup eth0" will still work,
> and it should stop anything else from doing it.
> --
> derek
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