I was reading a Proxy ARP paper from Cisco and in the example there were two computers (among others) that were configured as such:
Host A: 172.16.10.100/16
Host B: 172.16.20.200/24
The paper said "Host A believes that it is directly connected to all of network 172.16.0.0"
Does this mean that the 172.16.0.0 /16 network can communicate to any 172.16.x.x network? (x.x being numbers). I always thought of 172.16.0.0 network being different from 172.16.20.0 /24. Is this not the case because this addresses is subnetted?
Subnet 172.16.10.100 /16
having the subnet block from 172.16.0.1 - 172.16.255.255, so the HostB's subnet also included on this. Hence obviously Host A can communicate with HostB. As well as from HostB's point of view the network Address will be 172.16.20.1 and Bradcast will be 172.16.20.255 so the traffic wont go beyond this.
It helps to remember that the subnet mask is applied on a node, so if Host A's address is 172.16.10.100/16 then Host A thinks it is on the network 172.16.0.0 and so, as far as host A is concerned, anything with the address 172.16.x.x is on it's local network. Host B (172.16.20.200/24 ) will have a different opinion because the key is to consider which host you are sitting in and looking out at the world from
Host B is on a different network to Host A from Host B's point of view, but not from Host A's point of view. From Host A's point of view they are on the same network. The outcome all depends on the mask set at each node