A network has 3 subnets - X, Y and Z. There are 65, 21 and 30 hosts present in the X, Y and Z subnets respectively. The subnets share the 24 high-order bits of the 138.32.130.0/24 address space.

Your manager has requested you to calculate subnet addresses to each of the subnets with the following goals -

• leave the largest possible contiguous address space available for assignment in case a new subnet were to be added.
• the amount of address space assigned is minimal;

Please answer the following questions showing logic and calculations based on the above criteria:

a. What is the theoretical maximum number of hosts allowed here?

b. What are the subnet addresses of subnets X, Y and Z?

c. What are the broadcast addresses of subnets X, Y and Z?

Question 2: Network Address Translation [16 x 0.5 = 8 Marks]

Three computers are connected together in a local network having IP addresses 10.0.1.14, 10.0.1.16 and 10.0.1.19. Between the hosts and the rest of the internet is a NAT-enabled switch/router. The host with IP address 10.0.1.19 sends an IP datagram destined to host 128.119.166.186. The source port is randomly selected as 3368 and the destination port as 80.

NAT translation table WAN side addr LAN side addr 135.122.200.211 10.0.1.19 2 S: D: 10.0.1.28 S: 1 D: S: 3 S S: D: 135.122.200.211 D: 10.0.1.14 4 4 10.0.1.16 10.0.1.19