PCI Ethernet Card moves eth* ports around

Hi all,
I've got a problem configuring ethernet ports. I'm running RedHat
Enterprise Linux ES on a Dell 2550 server, which has two built in
Ethernet ports the systems assigns to eth0 (which is a gigabit port)
and eth1. I'm trying to install a two port PCI Ethernet card into the
system. When I do this the order of the eth* devices is different; eth1
becomes eth0, eth1 and eth2 are on the external card and the gigabit
port becomes eth3.

I've tried to control this behavior by creating a /etc/mactab file, and
putting a call to /sbin/nameif in the /etc/hotplug/net.agent file,
according to what looked like a solution at this link:
http://groups-beta.google.com/group/...c5e82f29a97018
But that doesn't seem to help, and in fact seems to mess things up. The
system comes up setting the ports in a seeming arbitrary, and I'd
swear, random manner.

Does anyone know what's going on here, or could offer me some advice
where to look to solve this problem?

Thanks,
Doug Farrell

> I've tried to control this behavior by creating a /etc/mactab file, and
> putting a call to /sbin/nameif in the /etc/hotplug/net.agent file,
> according to what looked like a solution at this link:
> http://groups-beta.google.com/group/...c5e82f29a97018
> But that doesn't seem to help, and in fact seems to mess things up. The
> system comes up setting the ports in a seeming arbitrary, and I'd
> swear, random manner.
>
> Does anyone know what's going on here, or could offer me some advice
> where to look to solve this problem?

Without /etc/mactab and cousins, the order is determined in part by the
order of the mapping in /etc/modules.conf. That's good if your NIC's
use different drivers. If they use the same driver (e.g. 3C905B vs.
3C905C) the mapping is determined by the order in which the cards appear
on the PCI bus. While this doesn't change between boots, it is pretty
arbitrary.

Allen,

Thanks for the information, I will confirm the configuration stays the
same between boots and then probably just go with it. I've tried using
nameif and /etc/mactab but with no success. Of course I could be doing
something wrong, though it seems easy enough to use.
Thanks for your reply,
Doug

In article <(E-Mail Removed) .com>,
(E-Mail Removed) wrote:

>When I do this the order of the eth* devices is different; eth1 becomes
>eth0, eth1 and eth2 are on the external card and the gigabit port
>becomes eth3.

Yes, but that should be consistent as long as you don't change hardware.
It's a BIOS thing.

>The system comes up setting the ports in a seeming arbitrary, and I'd
>swear, random manner.

In theory, moving crap around between PCI slots changes how the stuff
is discovered on boot. However, once you close the cover, things should
stay wherever they are. Then it's just the pain in the butt of moving
the /etc/sysconfig/network-scripts/ifcfg-eth? files to suit (if you have
three 100BaseT ports, and one Gigabit, then swapping the cables on the
three 100BaseT cards also works), and setting firewall rules, etc. You
should only have to do this when you change hardware, not every time
the system boots. If the NICs use different drivers, the Ethernet-HOWTO
suggests using alias lines in /etc/modules.conf to tell which is which.

If you have 'kudzu' installed/running, you may want to disable or toss it.
I don't know about you, but I hate software that thinks it knows what I
really want.

Old guy

Hey Old Guy,

Thanks for the reply, and from another old guy to boot! We ended up
putting a 3Com card in the system just to help us identify what was
what, but after that things would boot consistently, so that's good
enough. I'd take your suggestion about dumping kudzu, but I still
consider myself barely better than a novice linux user, so for the time
being I'm sticking with it.

Thanks again,
Doug

In article <(E-Mail Removed) .com>,
(E-Mail Removed) wrote:

>We ended up putting a 3Com card in the system just to help us identify
>what was what, but after that things would boot consistently, so that's
>good enough.

That's the name of the game!

>I'd take your suggestion about dumping kudzu, but I still consider myself
>barely better than a novice linux user, so for the time being I'm sticking
>with it.

That's fine too. I don't know about you, but neither my servers or work
stations get hardware changes that often, and when they do, we know about
it and are planning on making any setup changes that may be needed.

>Thanks again,

You're very welcome!

Old guy