[CALUG] Random Network Interfaces

[Randal T. Rioux]

On 04/14/2011 04:44 PM, Kevin wrote:
> I'd like to clarify one thing about the
> /etc/sysconfig/network-scripts/ifcfg-ethX files.  AFAIK, specifying the
> MAC address here only assigns your networking parameters to that
> interface if that MAC and interface name match what is specified in that
> file with what has already been configured by the OS via udev.  But it
> does NOT actually assign the interface device name to the NIC with the
> matching MAC address.  This is handled by udev, and if you need to
> change this you can do so in the
> /etc/udev/rules.d/70-persistent-net.rules file.
> 
> In fact, if your ifcfg-ethX file information doesn't match what is in
> the udev rules, you're going to end up with misconfigured interfaces
> when you reboot and networking may not function at all.  I've run into
> this situation a number of times due to cloning virtual machines, which
> of course causes the MAC addresses to change.  I have to be careful to
> match the correct MAC address to the correct device in udev or what I
> think should be eth0 might actually be eth2 or similar, then when the
> ifcfg-ethX scripts run, the OS starts trying to assign incorrect
> networks to those physical interfaces.

Thank you! This is exactly the info I needed.

Randy