Consider the scenario below in which three hosts, with private IP addresses $10\mathrm{.}0\mathrm{.}1\mathrm{.}13,10\mathrm{.}0\mathrm{.}1\mathrm{.}15,10\mathrm{.}0\mathrm{.}1\mathrm{.}22$ are in a local network behind a NAT'd router that sits between these three hosts and the larger Internet. 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 $10\mathrm{.}0\mathrm{.}1\mathrm{.}28,$ while the router's address on the Internet side has IP address $135\mathrm{.}122\mathrm{.}200\mathrm{.}205$

Before doing this problem, you might want to reread the section on the NAT protocol in section $4\mathrm{.}3\mathrm{.}4$ in the text.

$1.$ Consider the datagram at step $1,$ after it has been sent by the host but before it has reached the router. What is the source IP address for this datagram?

$2.$ At step $1,$ what is the destination IP address?

$3.$ Now consider the datagram at step $2,$ after it has been transmitted by the router. What is the source IP address for this datagram?

$4.$ At step $2,$ what is the destination IP address for this datagram?

$5.$ Will the source port have changed? Yes or No$.$

$6.$ Now consider the datagram at step $3,$ just before it is received by the router. What is the source IP address for this datagram?

$7.$ At step $3,$ what is the destination IP address for this datagram?

$8.$ Last, consider the datagram at step $4,$ after it has been transmitted by the router but before it has been received by the host. What is the source IP address for this datagram?

$9.$ At step $4,$ what is the destination IP address for this datagram?