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Subject8139too and curious arp corruption on multi-homed hosts
Hi guys,

Imagine two machines, a laptop with 4 network cards (only 2 relevant here)
and a desktop with 3 network cards (only 2 relevant here). All NICs are on
different subnets and different physical networks (a switch and a hub) --
nothing clever like sharing the same physical network whatsoever...

Now, the problem is -- the interface on the laptop driven by 8139too NIC
doesn't work. It generates interrupts but no packets get through.
tcpdump-ing the situation from the desktop revealed that the 8139too
interface did not reply to arp requests most of the time. But when the arp
reply did come through it was registered onto the wrong interface on the
desktop! Like this (from the desktop):

# arp -a
penguin.homenet ( at 00:50:DA:D9:98:E9 [ether] on eth0
penguin37.homenet ( at <incomplete> on eth1
cisco.homenet ( at 00:40:F9:17:F6:B2 [ether] on eth0
penguin37.homenet ( at 00:A0:D2:11:B6:5D [ether] on eth2
penguin48.homenet ( at 00:D0:B7:23:B4:B8 [ether] on eth2

penguin37 is the 3.7 interface on the laptop (8139too) and it should talk
to eth1 (3.1) of the desktop but the arp entry says eth2 (4.8) interface
which has nothing to do with it. Manually deleting it (arp -d penguin37)
didn't help -- the eth1 entry still remained <incomplete> and so I can't
ping penguin37 from desktop and can't ping desktop's "saturn31" (3.1
interface) from the laptop.

Any ideas?

I tried downing/rmmod-ing all other NICs so that no interrupt sharing
occurs on the 8139too side -- didn't help. All other interfaces (the on
the laptop function absolutely fine.

Both machines run 2.4.0-test9-pre9, of course.


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