[Cialug] Basic Networking ARP and Routers

[Dave Weis]

Check your subnet mask on the 10.1.88.250 device.



On Thu, Jul 24, 2014 at 3:04 PM, Nick Graber <nick at graber.me> wrote:

> The Schneider PLC is using ARP outside of it's subnet and expecting a reply
> from the router with it's MAC to make a connection with the AB PLC I think.
>  Should the router replay to such and inquiry or should the PLC do an ARP
> for the Default Gateway then send the packet to the Default Gateway?  It
> appears it is using ARP to try and discover the router that controls
> 172.20.87.255 and I'm not sure that is possible.
>
>
> Wan{
>     Schneider PLC [10.88.1.250]
>     Sixnet Router WAN [10.88.1.254]
> }
>
> Lan{
>     Sixnet Router LAN [172.20.87.1]
>     AllenBradly PLC [172.20.87.235]
> }
>
>
> Example Packet Capture:
>
> https://www.dropbox.com/s/s75m34lhu47y9rr/IOScanner.pcapng
>
> Thanks,
> Nick Graber
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