Actually, the FIRST thing (this is my take on ARP) that it does it compare
the destination IP address to it's own IP address using the subnet mask.
If the determination is that it is on it's own subnet, it simply checks the
ARP cache and (if need be performs the ARP for the IP to MAC conversion) and
sends the traffic via Layer 2 MAC communication.
If the determination is that it is on another subnet, it does the same
thing, but it uses it's gateway IP address as the destination, checks ARP
cache, etc.......
What you said below is correct, however, I believe that the comparison of
the dest. IP and the source IP using subnet mask happens before any ARPing
goes on.
Mike W.
"Dennis Laganiere" wrote in message
[EMAIL PROTECTED]">news:[EMAIL PROTECTED]...
> I'm trying to describe the ARPing process. It something I've always taken
> for granted, but now I'm trying to actually write it down. Let me know
your
> thoughts...
>
> When a workstation attempts to communicate with an IP address it follows
> this process:
>
> IP devices maintain an ARP cache that store any recently acquired
IP-to-MAC
> address combinations. If the appropriate address is there, communication
is
> established.
>
> If the IP address is not in the local ARP table, the source host will send
> an ARP request packet containing the Network-layer address, seeking to be
> resolve it to a MAC-layer address for the desired destination.
>
> All hosts on the network receive this request, but only the host with the
> specified network address will respond. If present and functioning, the
> host with the specified address responds with an ARP Reply packet
containing
> its MAC-layer address. The originating device receives the ARP Reply
> packet, stores the MAC/IP address combination its ARP cache for future
use,
> and begins exchanging packets with the host.
>
> If the host is not on the local network, the router on the local network
> will look up the network address in its route table and if it finds a
match,
> it will return the MAC address of its local interface to the ARP-ing
source
> station.
Message Posted at:
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