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From: Tom Ierna <tom@shockergroup.com>
To: Anuj Singh <anujhere@gmail.com>
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Date: Fri, 3 Apr 2009 20:32:31 -0400
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Subject: Re: mac arp moved from-to DOS?
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On Apr 3, 2009, at 7:11 PM, Anuj Singh wrote:
> 4 03:23:19 fbsd7 kernel: arp: 10.139.7.15 moved from 00:22:19:ae:ea:0d
> to 00:22:19:ae:ea:0f on age0
> Apr  4 03:23:19 fbsd7 kernel: arp: 10.139.7.15 moved from
> 00:22:19:ae:ea:0f to 00:22:19:ae:ea:0d on age0
>
> 10.139.7.15 is some windows machine...


Does this Windows machine have two Ethernet cards plugged into the  
same network?

It looks like your FreeBSD machine is seeing that IP address switch  
between two MAC addresses.

This can be indicative of a network loop between the interfaces on the  
machine with that IP address, or a DHCP client fight.

I've also seen this (harmlessly) manifest with certain FreeBSD  
firewalls in bridged mode.

-Tom