Netstat DRop/-D command

You can terminate a specific TCP/IP socket endpoint using the Netstat DRop/-D command.

When a DRop command is issued against a socket endpoint, any outstanding or following socket calls that refer to the socket that is being dropped terminate with a negative return code.

The socket endpoint that you drop can be a listening TCP server socket endpoint, a fully connected TCP socket (either server or client connection endpoint), or a UDP socket endpoint. When you drop a TCP connection or UDP endpoint, the associated socket does not close. The application that owns the associated socket is responsible for closing the socket.

The DRop/-D command terminates the socket endpoint that is identified by the connection number n. You can determine the connection number from the Conn column in the Netstat COnn/-c or Netstat TELnet/-t display.

You can use this parameter only if the MVS™.VARY.TCPIP.DROP security product resource is defined and the user ID that is associated with the DROP command is permitted to this resource.

Use the DRop/-D command to terminate an individual TCP connection when you do not want to terminate the server itself, but want only to drop an individual connection with that server.

Use the DROP/-D command to terminate old TCP connections if they prevent a server from being restarted. This is sometimes necessary when the server does not enable the SO_REUSEADDR socket option before binding to its well-known port.

If you want to terminate all socket activity from a specific sockets application, terminate the application using the appropriate mechanism that is provided by the application. The DRop/-D command can have unpredictable results when issued against a listening socket or UDP socket. Some applications might not handle the subsequent socket errors as expected.

Restriction: The Netstat DRop/-D command supports dropping only one TCP connection per command invocation. The VARY TCPIP,,DROP command provides the ability to drop all TCP connections that are associated with a server. See VARY TCPIP,,DROP for more information.