2. TCP Port Service Multiplexer
The TCP Port Service Multiplexer (TCPMUX) is
a little-used Internet protocol defined in RFC
1078. The specification describes
a multiplexing service that may be accessed with
a network protocol to contact any one of a
number of available TCP services of a host on a
single, well-known port number.[1]
3. Echo Protocol
The Echo Protocol is a service in the Internet
Protocol Suite defined in RFC 862. It was
originally proposed for testing and measurement
of round-trip times in IP networks.
4. Discard Protocol
The Discard Protocol is a service in the Internet
Protocol Suite defined in RFC 863. It is intended
for testing, debugging, and measurement
purposes.
5. File transfer
file transfer is a generic term for the act
of transmitting files over a computer network like
the Internet.