arp: <some ether addr> is using my IP address <some IP addr> again.

[Mike Hunter]

On May 19, "Russell Adams" wrote:

> I have seen this question posted twice to the list each without any response. 
> Does anybody out there know if this is possible, a Yes or No, will do if you
> can't offer anything else. If it is possible then how do we get rid of the
> Arp/IP conflict problem.
> 
> This is what I want to do:
> 
> A transparent bridge with no IPs (2 NICs)
> A 3rd NIC to access the box via SSH for monitoring and configuration.
> 
> this is what I have done.
> 
> xl0 and xl1 set up as a transparent bridge, no ips
> rl0 set up as 192.168.30.254 on the LAN
> Bridge is inbetween 192.168.30.1 (ROUTER to Internet) and 5500 Cisco Switch.
> 
> I log in via SSH to configure the bridge via rl0, so far so good. I plug in the
> bridge between the router and the switch via xl0 and xl1, the bridge begins to
> pass packets perfectly. BUT now rl0 is not reachable via anything, no even a
> ping. Login into the console for investigation I find this message:
> 
> FreeBSD Kernel: Arp: 00:00:00:00:00 is using my IP address 192.168.30.254
> FreeBSD Kernel: Arp: 11:11:11:11:11 is using my IP address 192.168.30.254
> 
> The 00 and 11 MACs address representing the MAC for the 2 NICs that are part of
> the bridge. 192.168.30.254 was the previously working admin interface accepting
> conections via SSH.
> 
> Below is are 2 unanswered posts that are  asking the same thing but both are
> regarding 4.8, I am using 5.2.1
> 
> 
> http://lists.freebsd.org/mailman/htdig/freebsd-net/2003-June/000586.html
> http://lists.freebsd.org/mailman/htdig/freebsd-net/2003-December/002109.html

I never had any trouble passing traffic, but I did get spurious arp error
messages.  In my /etc/rc.conf, I specifically disabled arp on the bridge
interfaces, and the messages went away.  I think I saw that suggestion on
an archived mailing list post somewhere.

Good luck,

Mike