in.discardd - UDP or TCP discard protocol service
The in.discardd service provides the server-side of the discard protocol. This protocol is used for debugging and bandwidth measurement and is available on both TCP and UDP transports through port 9.
The discard service simply throws away any data it receives from the client.
Once a connection is established, the in.discardd discards any data received. No response is generated. The connection remains open until the client terminates it.
The in.discardd listens for UDP datagrams. When a datagram is received, the server discards it. No response is sent.
See attributes(7) for descriptions of the following attributes:
Postel, J. RFC 863, Discard Protocol. Network Working Group. May 1983. https://tools.ietf.org/html/rfc863
The in.discardd service is managed by the service management facility, smf(7), under the service identifier:
Administrative actions on this service, such as enabling, disabling, or requesting restart, can be performed using svcadm(8). Responsibility for initiating and restarting this service is delegated to inetd(8). Use inetadm(8) to make configuration changes and to view configuration information for this service. The service's status can be queried using the svcs(1) command.
The in.discardd program and the svc:/internet/discard:default service were added in the Solaris 10 3/05 release. Prior to that, support for the discard service was provided as a builtin part of inetd(8) since the initial release of Solaris.
Support for IPv6 was added in Solaris 8.
The discard service was enabled by default in releases up through Solaris 9, but has been disabled by default since the Solaris 10 3/05 release.