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From: Peter Curran <peter@gate.ticl.co.uk>
Message-Id: <199704290953.KAA11005@gate.ticl.co.uk>
Subject: Funny ARP problem
To: stable@freebsd.org
Date: Tue, 29 Apr 1997 10:53:58 +0100 (BST)
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Hi guys

I got a funny problem with ARP on a 2.1.7-R box.

I have an ethernet interface (3com 3c509) which has two IP addresses,
one the primary is (e.g.) 200.1.1.1 and the alias is 200.1.1.1.

If I ping another box on the 100.1.1 net, say 100.1.1.2, then I get
no reply.  If I ping on the 200.1.1 net I get a reply.

Putting an analyser on the net I can see that if I ping 100.1.1.2 then
the arp request is FROM 200.1.1.1 -> 100.1.1.2.  If I ping 200.1.1.2
then the arp message is correct.

I have never observed this behaviour before and normally have multiple
addresses bound to a single interface from different nets.  I have only
very recently upgraded this box to 2.1.7 and the extra address is new
so I am not sure what has caused the breakage.

Am I missing something really obvious here?

Any help or suggestions gratefully received.

Cheers

Peter