Re: IP4 address conservation method

[Dan White <dwhite () olp net>]

On 06/05/13 18:57 +0200, Mikael Abrahamsson wrote:
> On Wed, 5 Jun 2013, William Herrin wrote:
>
> > Nothing. The problem is that the arp source IP doesn't fall within the
> > interface netmask at the receiver. Some receivers ignore that... after
> > all, why do they care what the source IP is? They only care about the
> > source MAC. Other receivers see a spoofed packet and drop it.
>
> Why wouldn't it be within the source IP mask? I would imagine 
> local-proxy-arp would work exactly the same way as if a directly 
> connected host with the IP the ARP request was for would have 
> answered.

I've seen two vendors get it wrong: 1) when originating an ARP request, the
router uses a source IP that does not match the subnet of the ip being
requested (happened when the interface on the router had secondary IPs); 2)
when a customer had more than IP address assigned on an interface/VLAN, and
one device ARPd the other, the router responded with its own MAC, creating
a race condition where sometimes traffic between those two devices was
forced up through the router.

--
Dan White