I've already responded to this under the "OT" tag so take a look at that
reply if you're interested.

For the meantime, I'll reply in sequence below:


Justin Richards wrote:
> Hi Folks,
>
> my understanding of arp tables is that when a layer 3 packet is
> destined for a given ip an arp request is sent out the adapter.
>   


Yes, the purpose of the ARP request is to figure out what MAC address
the frame should be sent to.


> The arp request is in the form of 'who has ip 192.168.0.1'.  If that
> host 192.168.0.1 is on the network segment then it will reply with its
> mac address.


Correct.


>   This is then added to the arp table and the packet is
> encapsulated with the layer 2 frame with the destination mac it just
> learnt.
>   


Correct.


> If the destination host is via a router then the router will respond
> with its mac address and the packet is encapsulated with that mac
> address and the router takes care of it.
>   


If you go through a router such as 10.10.10.1, then you send out an ARP
request for 10.10.10.1, you do *not* send out an ARP request for
192.168.0.1.

In order to find out which router you should go through to get to a
particular address (or even if you need to go through a router at all),
you consult your Route Table.


> I am experincing conflicting results on what appears to be identicle
> setups as follows:-
>
> 1. Any destination ip address handled by the gateway device does NOT
> result in an arp entry but all local ip address are added.
>   


Correct. But it *will* results in the router's address being added to
the ARP table.


> 2. Any destination ip address handled by the gateway device does
> result in an arp entry but all local ip address are added.
>   

You'll never see an ARP table entry for a device that isn't on the same
Ethernet wire. (Please don't bring up the topic of VPN's haha)

 I tried to give an explanation of how it all works in my other "OT" reply.

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