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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

On Linux, FreeBSD, 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.

See also

External links

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