The routing table of a router is shown below :On which interface

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The routing table of a router is shown below :

On which interface will the router forward packets addressed to destinations 128.75.43.16 and 192.12.17.10 respectively?

1. Eth 1 and Eth 2
2. Eth 0 and Eth 2
3. Eth 0 and Eth 3
4. Eth 1 and Eth 3

Correct Option: A

To find the interface, we need to do AND of incoming IP address and Subnet mask. Compare the result of AND with the destination. Note that if there is a match between multiple Destinations, then we need to select the destination with longest length subnet mask. 128.75.43.16, matches with 128.75.43.0 and 128.75.43.0, the packet is forwarded to Eth1 as length of subnet mask in Eth2 is more. If a result is not matching with any of the given destinations then the packet is forwarded to the default interface (here Eth2). Therefore the packet's addressed to 192.12.17.10

Hence, option (a) is correct.