Which IP address is the source IP?

Refer to the exhibit.

An engineer configured NAT translations and has verified that the configuration is correct.

Which IP address is the source IP?
A . 10.4.4.4
B. 10.4.4.5
C. 172.23.103.10
D. 172.23.104.4

View Answer

Answer: D

Explanation:

NAT is used to send a packet to the outside network, using a public IP address to make it routable. The NAT logic is "inside-to-outside" FIRST and "outside-to-inside" THEN. This way, configuring NAT means "choosing a public IP address" for any outbound packet" IN THE FIRST PLACE, where "public IP address" translates to "inside global address". Among the given answers, the only inside global address is 172.123.104.4.