The DISCARD protocol
is an Internet protocol
defined in RFC 863. It is intended for testing and measurement purposes.
A host may send data to a host that supports the DISCARD protocol, on either TCP or UDP port 9. Everything sent to the server is discarded. No response is sent back.
Inetd implementation of DISCARD
, and other UNIX-like
operating systems a discard server is built into the inetd daemon
. The discard service is usually not enabled by default. It may be enabled by adding the following lines to the file /etc/inetd.conf
and telling inetd to reload its configuration:
discard stream tcp nowait root internal
discard dgram udp wait root internal
Examples of use
- The TCP/UDP equivalent of /dev/null. Such a service is guaranteed to receive what is sent to it and can be used for debugging TCP and/or UDP code requiring a guaranteed reception of payload sent.
- RFC 348, The Discard process
- RFC 863, The Discard protocol