The IP address 127.0.0.1 is used to test the IP stack on an individual node. What is IP stack here ?Some blogs redirects this question to TCP/IP stack.But I am unable to co relate and understand it.
TCP/IP Illustrated Volume 1 discusses at a high level how the loopback address works in the context of an Ethernet driver (see Chapter 2 Section 7, and diagram 2.4). The reason why pinging the loopback address is used is because it verifies the correct operation of the TCP/IP "stack" on a system without it needing to be connected to anything else. Here "stack" is used to refer to a software suite, not a conceptual model, such as the TCP/IP model.