Problem $1(10$pts$)$: Consider the scenario below in which three hosts, with private IP addresses $10\mathrm{.}0\mathrm{.}1\mathrm{.}14,10\mathrm{.}0\mathrm{.}1\mathrm{.}16,10\mathrm{.}0\mathrm{.}1\mathrm{.}18$ are in a local network behind a NATted router that sits between these three hosts and the larger Intemet. IP datagrams being sent from, or destined to$,$ these three hosts must pass through this NAT router. The router's interface on the LAN side has IP address $10\mathrm{.}0\mathrm{.}1\mathrm{.}25,$ while the router's address on the Internet side has IP address $135\mathrm{.}122\mathrm{.}199\mathrm{.}211.$

Suppose that the host with IP address $10\mathrm{.}0\mathrm{.}1\mathrm{.}16$ sends an IP datagram destined to host $128\mathrm{.}119\mathrm{.}178\mathrm{.}183.$ The source port is $3412,$ and the destination port is $80.$

a$)$ Consider the datagram at step $1.$ What are the source and destination IP addresses for this datagram? What are the source and destination port numbers for the TCP segment in this IP datagram?

b$)$ Now consider the datagram at step $2.$ What are the source and destination IP addresses for this datagram? What are the source and destination port numbers for the TCP segment in this IP datagram? Identify the differences in datagram's IP addresses and port numbers between step $1$ and step $2.$ Specify the entry that has been made in the router's NAT table.

c$)$ Now consider the datagram at step $3.$ What are the source and destination IP addresses for this datagram? What are the source and destination port numbers for the TCP segment in this IP datagram?

d$)$ Last, consider the datagram at step $4.$ What are the source and destination IP address for this datagram? What are the source and destination port numbers for the TCP segment in this IP datagram? Identify the differences in datagram's IP addresses and port numbers between step $3$ and step $4.$