Subject: Re: [2.4 PATCH] bugfix: ARP respond on all devices

From: David T Hollis <[email-masked]>
Date: Sun, 17 Aug 2003 12:51:01 -0400

Carlos Velasco wrote:

>On 17/08/2003 at 16:28 Alan Cox wrote:
>
>  
>
>>Linux doesn't issue "bad" requests. Linux will reply when it is
>>asked for an address that it owns, as per RFC826, unless you chose
>>to change the behaviour with things like arpfilter.
>>    
>>
>
>We are not talking about ARP Replies, we are talking about ARP
>Requests.
>You can see the Richard post here, same issue I reported several weeks
>ago:
>http://marc.theaimsgroup.com/?l=linux-net&m=106094924813337&w=2
>
>==
>	On eth0, we see:
>
>11:23:55.650514 0:4:75:ca:c4:ef Broadcast arp 42: arp who-has
>10.10.10.1
>tell 212.xxx.yyy.9
>==
>
>Linux is sending an ARP Request to a LAN where the source IP address of
>the packet has not any sense in that IP network.
>And, at least, 2 RFCs are stating that other devices should not reply
>to this packet. Currently know Cisco, Foundry; possibly others, and
>possibly others coming as ARP storms are not desired.
>
>Regards,
>Carlos Velasco
>
>
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>
Check out: http://www.linuxvirtualserver.org/docs/arp.html.  I 
understand the problem you're talking about.  It's not a 'bug', it's a 
feature!  You need to use the hidden interface approach to have the back 
end system not broadcast it's MAC for the virtual IP.