CompTIA Network+ N10-006 Q25

A technician, Joe, needs to troubleshoot a recently installed NIC. He decides to ping the local loopback address. Which of the following is a valid IPv4 loopback address?

A. 10.0.0.1
B. 127.0.0.1
C. 172.16.1.1
D. 192.168.1.1

Correct Answer: B
Section: Network architecture

Explanation:
The loopback address is a special IP address that is designated for the software loopback interface of a computer. The loopback interface has no hardware associated with it, and it is not physically connected to a network. The loopback address causes any messages sent to it to be returned to the sending system. The loopback address allows client software to communicate with server software on the same computer. Users specify the loopback address which will point back to the computer’s TCP/IP network configuration.
In IPv4, the loopback address is 127.0.0.1.
In IPv6, the loopback address is 0:0:0:0:0:0:0:1, more commonly notated as follows. ::1