It is a test that a user performs to confirm that remote system is up and running on the network. This is needed when basic connectivity failure problem appears. Internet Control Message Protocol renders 2 messages for this service which are Echo Request and Echo Reply. Echo Request is a request sent to a destination device. This system acknowledges with an Echo Reply message. Echo request is generated by destination system with PING program. Ping program is used for testing basic connectivity. An echo reply is sent by target system to the requesting system acknowledging that the echo request has been received.
Terminal emulation, especially the unprotected <u>telnet </u>protocol, should be blocked from any access to all internal servers from the public network.
