Which of the following is an IP address that is private (i.e. reserved for internal networks, and not a valid
address to use on the Internet)?
A.
192.168.42.5
B.
192.166.42.5
C.
192.175.42.5
D.
192.1.42.5
Explanation:
The IP address 192.168.42.5 is in the private Class C IP address range.
The private IP address ranges are:
10.0.0.0–10.255.255.255 (Class A network)
172.16.0.0–172.31.255.255 (Class B networks)
192.168.0.0–192.168.255.255 (Class C networks)
Incorrect Answers:
B: 192.166.42.5 is not a private IP address. If the first octet is 192 then the second octet must be 168 for the
address to be private.
C: 192.175.42.5 is not a private IP address. If the first octet is 192 then the second octet must be 168 for the
address to be private.
D: 192.1.42.5 is not a private IP address. If the first octet is 192 then the second octet must be 168 for the
address to be private.Harris, Shon, All In One CISSP Exam Guide, 6th Edition, McGraw-Hill, New York, 2013, p. 605