If we have two interfaces connected to the the same VLAN (or even using a cross
connect) and if we assign addresses that belong to different subnets, they
cannot ping each other. I need help in understanding why.
My understanding is that when a packet is flowing down the OSI layers, based on
the IP and subnet, it understands whether the destination is in the local
subnet or not (if local, lookup the local arp cache, if not in the cache send
an ARP request b/c).
This ARP req - which is b/c - does not contain mask info. Only the destination
IP and source IP. So typically, a g/w will respond with it's MAC if it has a
route to the destination (and if proxy arp is configured). What if the
destination is another host physically connected to the source (same VLAN or
cross connect). It should see the ARP request, decapsulate it to L3, find that
the packet is destined for it. So why cant they communicate????
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