do the funky eth...

[der.hans]

moin, moin,

running into a new eth prob where I'm consulting.

Had a box the other day that had two ethernet cards, each with its own IP
addy. The addies happened to be on the same subnet and be hooked in to the
same switch. ifconfig and route were setup correctly. After shutting down
the second interface and disconnecting the cable the box kept answering
for it. First IP still worked too, so it wasn't just me getting things
backwards :).

Anyway, I would think that shouldn't work for a couple of reasons. First
the IP stack shouldn't allow it. Second the switch shouldn't be sending
packets for the second IP addy to the MAC addy of the primary card.

Today, ran into another prob. Needed to move a service from one box to
another. Had the second box ready. Instead of changing DNS and waiting for
updates, which would've not worked well with that service, I just swapped
IP addies. Took the old box off the air, changed the IP on the new
box, then brought the old box up on the IP from the new box. That works
fine, except they both continue to answer to the old IP addies, e.g. both
boxen think they have both IP addies. Networking is setup correctly. The
incorrect IP doesn't show up in ifconfig or route.

On the old box the arp entry for the old IP is munged. arp -d won't kill
the entry. Staticly setting the arp entry to the correct MAC addy doesn't
fix the problem.

On the new box the old IP isn't even in the arp table.

Doing much of this from the consoles. Everything works fine from other
boxen, e.g. service is only running on one box now and the correct box
responds.

Don't know if the following matters, but here it is anyway :). Both boxen
are running RH 6.2, but have the errata installed. The old box is running
2.2.16 and the new box is running 2.2.17. The service is something
develled in house, but it's just a tcp daemon and shouldn't affect the
networking.

Rebooting the old box didn't help.

Anybody have any ideas on what's wrong and how to fix it?

ciao,

der.hans
-- 
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