What is the IPv4 address 127.0.0.1 commonly known as?

What is the IPv4 address 127.0.0.1 commonly known as?

• A. Public IP
• B. Broadcast address
• C. Loopback address
• D. Multicast address

Answer: (C)

Loopback testing is about referring to the local machine itself. The IPv4 address 127.0.0.1 sits in the reserved loopback range (127.0.0.0/8), so any packets sent to it stay on the same host and aren’t put onto any network. This lets you test network software and inter-process communication on your computer without using a real network connection. It isn’t a public IP, since it isn’t routable on the internet. It isn’t a broadcast address, which would be used to deliver messages to all hosts on a local network, nor a multicast address, which targets a group of hosts. So, 127.0.0.1 is known as the loopback address.

Loopback testing is about referring to the local machine itself. The IPv4 address 127.0.0.1 sits in the reserved loopback range (127.0.0.0/8), so any packets sent to it stay on the same host and aren’t put onto any network. This lets you test network software and inter-process communication on your computer without using a real network connection. It isn’t a public IP, since it isn’t routable on the internet. It isn’t a broadcast address, which would be used to deliver messages to all hosts on a local network, nor a multicast address, which targets a group of hosts. So, 127.0.0.1 is known as the loopback address.