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)?
10.0.42.5
11.0.42.5
12.0.42.5
13.0.42.5
This is a valid Class A reserved address. For Class A, the reserved addresses are 10.0.0.0 - 10.255.255.255.
The following answers are incorrect:
11.0.42.5 Is incorrect because it is not a Class A reserved address.
12.0.42.5 Is incorrect because it is not a Class A reserved address.
13.0.42.5 Is incorrect because it is not a Class A reserved address.
The private IP address ranges are defined within RFC 1918:
RFC 1918 private ip address range
References:
3Com http://www.3com.com/other/pdfs/infra/corpinfo/en_US/501302.pdf
AIOv3 Telecommunications and Networking Security (page 438)
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