What prevents two devices in separate subnets to talk to each other?
When a device
d1 in subnet
S1 wants to talk to device
d2 in subnet
S2, it sends an ARP request. Given that
d2 are connected to the same switch, the switch will flood the broadcast ARP request all ports out.
d2 can recieve the request and reply with its MAC address sent to the MAC address of
d1 provided in the ARP request. Nothing prevents further communication of the devices.
- I am thinking that protocol is the only thing that dictates the usage of a gateway to communicate accross subnets?
- Would this be a reason to use VLANs to crop the broadcast domain?
- How do separate VLANs prevent
d2to communicate if the MAC addresses are previously known?