Problem $5$: NETWORK ADDRESS TRANSLATION.

Consider the scenario below in which three hosts, with private IP addresses $10\mathrm{.}0\mathrm{.}1\mathrm{.}10,10\mathrm{.}0\mathrm{.}1\mathrm{.}17,10\mathrm{.}0\mathrm{.}1\mathrm{.}21$

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 $10\mathrm{.}0\mathrm{.}1\mathrm{.}26,$ while the router's address on the Internet side has IP

address $135\mathrm{.}122\mathrm{.}192\mathrm{.}206.$

Suppose that the host with IP address $10\mathrm{.}0\mathrm{.}1\mathrm{.}17$ sends an IP datagram destined to host $128\mathrm{.}119\mathrm{.}169\mathrm{.}190.$ The

source port is $3490,$ and the destination port is $80.$

Please provide the $S($source$)$ and $D($destination$)$ for $1,2,3,$ and $4$ step in the above figure.