Comptia Security Plus Mock Test Q74

Review the following diagram depicting communication between PC1 and PC2 on each side of a router. Analyze the network traffic logs which show communication between the two computers as captured by the computer with IP 10.2.2.10.
DIAGRAM
PC1 PC2
[192.168.1.30]——–[INSIDE 192.168.1.1 router OUTSIDE 10.2.2.1]———[10.2.2.10] LOGS
10:30:22, SRC 10.2.2.1:3030, DST 10.2.2.10:80, SYN
10:30:23, SRC 10.2.2.10:80, DST 10.2.2.1:3030, SYN/ACK
10:30:24, SRC 10.2.2.1:3030, DST 10.2.2.10:80, ACK
Given the above information, which of the following can be inferred about the above environment?

A. 192.168.1.30 is a web server.
B. The web server listens on a non-standard port.
C. The router filters port 80 traffic.
D. The router implements NAT.

Correct Answer: D
Section: Network Security

Explanation:
Network address translation (NAT) allows you to share a connection to the public Internet via a single interface with a single public IP address. NAT maps the private addresses to the public address. In a typical configuration, a local network uses one of the designated “private” IP address subnets. A router on that network has a private address (192.168.1.1) in that address space, and is also connected to the Internet with a “public” address (10.2.2.1) assigned by an Internet service provider.

Incorrect Answers:
A: If that were true, then the routers IP address would not be the source.

B, C: The diagram shows that a TCP connection has been established. If these were happening, there wouldn’t be a connection established.

References:
https://technet.microsoft.com/en-us/library/dd469812.aspx
http://en.wikipedia.org/wiki/Transmission_Control_Protocol