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Que. Network Address Translation (10 pt.) (show all the details/assumptions/work

ID: 3692184 • Letter: Q

Question

Que. Network Address Translation (10 pt.) (show all the details/assumptions/work along with the table)
Consider the above network setup.

Suppose that the ISP instead assigns the router the address 24.34.112.235 and that the network address of the home network is 192.168.1/24.
Assume IP addresses in the home network as follows: 192.168.1.1, 192.168.1.2, 192.168.1.3 with the router interface being 192.168.1.4
Suppose each host has two ongoing TCP connections (i.e., 6 connections for three hosts in the figure), all to port 80 at host 128.119.40.86. Provide the six corresponding entries in the NAT translation table. Assume that the router assigns the WAN side port number from 4000 and increments, and that each host assigns a source port number incrementally from 3345 to 65535. Refer to Figure 4.22 in the textbook and slide 4-61.

NAT translation table
WAN side address LAN side address

NAT translation table WAN side LAN side 138.76.29.7, s001 10..01, 3345 138.76.29.7, 5001 10.0.0.1, 3345 S= 10.0.0.1, 3345 D = 1 28.1 1 9.40.1 86, 80 10.0.0.1 s = 138.76.29.7, 5001 D = 1 28.1 1 9.40.1 86, 80 2 10.0.0.4 10.0.0.2 138.76.29.7 4 s= 128.119.40.186, 80 D 138.76.29.7, 5001 S D 1 28.1 1 9.40.1 86, 80 10.0.0.1, 3345 3 10.0.0.3

Explanation / Answer

Given the IP addresses of the network is

192.168.1.1,

192.168.1.2,

192.168.1.3

router interface is

192.168.1.4

And the host has two ongoing TCP connections with 6 connections for three hosts in the figure), all to port 80 at host 128.119.40.86. Ihe router assigns the WAN side port number from 4000 and increments,then the NAT translation table of the figure that is given is:

WAN side address       LAN side address 124.34.112.235, 4000 192.168.1.1, 3345 124.34.112.235, 4001 192.168.1.1, 3346 124.34.112.235, 4002 192.168.1.2, 3445 124.34.112.235, 4003 192.168.1.2, 3446 124.34.112.235, 4004 192.168.1.3, 3545 124.34.112.235, 4005 192.168.1.3, 3546