Re: How does "alias ethX drivername" in modules.conf work?

Andrzej Krzysztofowicz
2001-08-08T08:42:06Z

"Riley Williams wrote:"
> > If I build a system with several identical (other than MAC)
> > FooCorp PCI ethernics, they will number up in order of ascending
> > MAC address.
> >
> > I take the same system, replace the FooCorp cards with BarInc
> > NICs, they will number up in reverse MAC address.
> >
> > Replace them instead with Baz Systems NICs, and I get them in
> > bus scan order (at which point I'm dependent on the firmware
> > version of my PCI bridge too!).
> >
> > And if I elect to use Frob Networking NICs, I instead get them
> > in the *random* order that their oncard processors won the race
> > to power up.
> >
> > Gods and demons help me if I try putting several of all four
> > brands in one box, or the firmware on my NICs or in my PCI
> > bridges changes!
>
> I dealt with this problem in a previous email, but will repeat it for
> your benefit. The ONLY provisos I will use are the following two:
>
> 1. All ethernet interfaces in your machine have distinct MAC's.
>
> 2. If the firmware in your NIC's changes, the MAC's do not.
>
> Providing both of these are met, the enclosed BASH SHELL SCRIPT
> implements the `ifconfig` command with the port name replaced by its
> MAC address.

1. NFS-root needs to have RARP/NFS servers on eth0.
How can you deal with it if you have two boards supported by a single
driver and, unfortunately, the one you need is detected as eth1 ?
Assume that you cannot switch them as they use different media type...

> With this change, it doesn't actually matter what port name a
> particular interface is given, because ALL of the other network config
> tools refer to the interface by its assigned IP address, not its port
> name. As a result, if its port name changes between boots, the routing
> automatically changes with it.

2. ipfwadm / ipchains / iptables may use interface names,
3. dhcpd may need interface names to be provided,
4. you may want to pass an interface name argument to tcpdump...

In 2.2+ you can deal with 2.-4. changing interface names using ip from
iproute2. But I doubt whether ifconfig based scripts would work properly
then. And problem 1. is still valid ...

--
=======================================================================
Andrzej M. Krzysztofowicz ankry@mif.pg.gda.pl
phone (48)(58) 347 14 61
Faculty of Applied Phys. & Math., Technical University of Gdansk