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, SYN10:30:23, 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.

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.

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