Request for Comments: 863
This RFC specifies a standard for the ARPA Internet community. Hosts on the ARPA Internet that choose to implement a Discard Protocol are expected to adopt and implement this standard.
A useful debugging and measurement tool is a discard service. A discard
service simply throws away any data it receives.
TCP Based Discard Service
One discard service is defined as a connection based application on TCP. A server listens for TCP connections on TCP port 9. Once a connection is established any data received is thrown away. No response is sent. This continues until the calling user terminates the connection.
UDP Based Discard Service
Another discard service is defined as a datagram based application on UDP. A server listens for UDP datagrams on UDP port 9. When a datagram is received, it is thrown away. No response is sent.