Re: Why eth1 and not eth0 ?

[Matthew Saltzman <mjs ces clemson edu>]

On Tue, 23 Jan 2007, Dan Williams wrote:

> On Tue, 2007-01-23 at 20:38 -0400, Derek Broughton wrote:
> > On Tuesday 23 January 2007 19:53, Timothy Murphy wrote:
> > > On Tuesday 23 January 2007 23:31, Derek Broughton wrote:
> > > > > As a matter of interest, why has my NetworkManager
> > > > > started using eth1 in place of eth0, which it used to use?
> > > >
> > > > Probably you are using a different card...
> > >
> > > Same card. Sorry
> > >
> > > > > Is there anywhere I can specify which device I want to use?
> > > >
> > > > If so, check /etc/iftab
> > >
> > > [tim martha ~]$ less /etc/iftab
> > > /etc/iftab: No such file or directory
> >
> > In which case, investigate whether iftab is available under your distro - it's
> > used in Ubuntu to tie a MAC address to a specific interface. As Dan said,
> > udev can assign the interface numbers apparently randomly (my eth0 & eth1
> > frequently exchange positions, but my network configuration is set up so as
> > not to care).
>
> And that's the point; NM means you don't _need_ to care what the device
> name is.  Really, you shouldn't ever need to look at it, nor care what
> it's value is.  I don't tie my devices to MAC addresses, and they switch
> around every now and again, but it doesn't matter to me as they always
> do the right thing under NetworkManager.

Sometimes it does make a difference, though, to other tools.  I have an 
annoying license manager for some commercial software that keys off the 
HWADDR of eth0.  When they flip, I can't run my software.  GNOME's network 
monitor applets get very confused when the wireless and wired interfaces 
flip.

If this is Fedora, make sure you have the latest initscripts.  In Red Hat 
and Fedora, the hardware bindings are in 
/etc/sysconfig/network-scripts/ifcfg-eth*.

--
		Matthew Saltzman

Clemson University Math Sciences
mjs AT clemson DOT edu
http://www.math.clemson.edu/~mjs