I have a networking concept that I'm having difficulty understanding where I hope someone can point me in the right direction. If I have the following configuration for a router, and it receives a packet with a source address of
192.168.1.35and a destination address of
192.168.1.85, what interface will the router forward the packet from?
interface fastethernet 0/1
interface fastethernet 0/1.1
encapsulation dot1q 1
ip address 192.168.1.62 255.255.255.224
interface fastethernet 0/1.2
encapsulation dot1q 2
ip address 192.168.1.94 255.255.255.224
interface fastethernet 0/1.3
encapsulation dot1q 3
ip address 192.168.1.126 255.255.255.224
So my understanding is that each subnet is a
/27 subnet, which have
30 available hosts (considering network and broadcast addresses).
I believe that the address range for the first subnet will therefore be
192.168.1.62-92 and therefore the packet will be forwarded from
fe 0/1.1. However, in a practice exam, I'm told the answer is in actual fact
fe 0/1.2. Could anyone tell me why this is? Or point me to a resource that explains this. As I'm not sure how a packet could be forwarded from this port when I assume the range would be 192.168.1.94-124.
Despite this, I may be assuming that the router IP address is allocated for the first host in the subnet. If the router was the last host in the subnet then perhaps this could be understood where:
192.168.1.63 (Network Address)
192.168.1.64 (1st Addressable Host)
192.168.1.94 (Router (Default GW))
I think I may have worked this out while I wrote this question but I would appreciate confirmation.