[lug] Arp bug in 2.4.20-30 kernels?

[Warren Sanders]

Scott Herod wrote:
> Hello all,
> 
> I've got two machines running kernel 2.4.20-30.8.legacy.  These share an
> IP address, taking turns as to which is currently using it.  (The system 
> uses the Linux-HA project code to do this.)
> 
> ...
> 
> A couple of questions:
> 
> Has anyone ever heard of a bug reported against the 2.4 kernels in which
> they respond positively to an arp but don't show the IP address
> configured?
> 
> If the router forwards to an interface via its MAC address, will the 
> kernel refuse to accept the packets if the MAC address is right but it 
> doesn't believe that it owns the associated IP address?
> 

I have experience similar.  I first noticed probably with the 
kernel-smp-2.4.20-31.9 but continues with kernel-smp-2.4.20-37.9.legacy. 
My example is when I have a machine such as a SmoothWall router with two 
physical nic's on two totally separate networks.

Arpwatch will see a flip-flop a couple times a day.  However when checking 
the router (ifconfig) it does not reflect the reported changes.  Although 
not completely sure, but I do see some inaccessibility going through the 
local side.  But after pinging out of the router to the local network, I 
then can regain access again.  Doing this does not generate another arp 
report either.

I have not taken a look to find bug reports on this issue either.  So far 
you are the only one I have related to.  At the moment it isn't mission 
critical for me, so it can wait for me to upgrade this spring.

-- 
Warren Sanders
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