Networking Basics

[InnerPeace]

Testing connectivity with ping

This page will explain how the ping command is used to test network connectivity.

Ping is a basic program that verifies a particular IP address exists and can accept requests. The computer acronym ping stands for Packet Internet or Inter-Network Groper. The name was contrived to match the submariners' term for the sound of a returned sonar pulse from an underwater object.

The ping command works by sending special Internet Protocol (IP) packets, called Internet Control Message Protocol (ICMP) Echo Request datagrams, to a specified destination. Each packet sent is a request for a reply. The output response for a ping contains the success ratio and round-trip time to the destination. From this information, it is possible to determine if there is connectivity to a destination. The ping command is used to test the NIC transmit and receive function, the TCP/IP configuration, and network connectivity. The following types of ping commands can be issued:

ping 127.0.0.1 – This is a unique ping and is called an internal loopback test. It is used to verify the TCP/IP network configuration.
ping IP address of host computer – A ping to a host PC verifies the TCP/IP address configuration for the local host and connectivity to the host.
ping default-gateway IP address – A ping to the default gateway indicates if the router that connects the local network to other networks can be reached.
ping remote destination IP address – A ping to a remote destination verifies connectivity to a remote host.