End TCP/IP Connection (ENDTCPCNN)

Where allowed to run: All environments (*ALL)
Threadsafe: No
Parameters
Examples
Error messages

The End TCP/IP Connection (ENDTCPCNN) command is used to end a Transmission Control Protocol/Internet Protocol (TCP/IP) connection. This command ends a connection immediately and should be used only when a normal end is not possible.

Note: The ENDTCPCNN command is usually used by specifying option 4 on the Work with TCP/IP Connection Status list of the WRKTCPSTS (NETSTAT) display. The ENDTCPCNN command is provided as a separate command to give system administrators control over this function. By limiting the authority to the ENDTCPCNN command, the system administrator limits which users can end TCP/IP connections without restricting access to the NETSTAT utility.

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Parameters

Keyword Description Choices Notes
PROTOCOL Protocol *UDP, *TCP Required, Positional 1
LCLINTNETA Local internet address Character value, * Required, Positional 2
LCLPORT Local port 1-65535 Required, Positional 3
RMTINTNETA Remote internet address Character value, * Optional, Positional 4
RMTPORT Remote port 1-65535, * Optional, Positional 5
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Protocol (PROTOCOL)

Specifies the protocol used by the connection that is to be ended.

This is a required parameter.

*UDP
The connection was created for use with the User Datagram Protocol (UDP).
*TCP
The connection was created for use with the Transmission Control Protocol (TCP).
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Local internet address (LCLINTNETA)

Specifies the local internet address of the connection to end.

This is a required parameter.

*
The local internet address was left unspecified when this connection was opened.

Note: If '*' is specified, an attempt will be made to end both IPv4 and IPv6 connections that have an unspecified local internet address. To end only an IPv4 connection that has an unspecified local internet address, specify '0.0.0.0' (the null IPv4 address) for the LCLINTNETA value. To end only an IPv6 connection that has an unspecified local internet address, specify '::' (the null IPv6 address) for the LCLINTNETA value.

character-value
Specify the local internet address.

An IPv4 address is specified in the form nnn.nnn.nnn.nnn, where nnn is a decimal number ranging from 0 through 255. An IPv4 address is not valid if it has a value of all binary ones or all binary zeros for the network identifier (ID) portion or the host ID portion of the address.

An IPv6 internet address is specified in the form x:x:x:x:x:x:x:x, where x is a hexidecimal number ranging from 0 through X'ffff'. "::" may be used once in the IPv6 address to indicate one or more groups of 16 bits of zeros. The "::" may be used to compress leading, imbedded, or trailing zeros in the address. An IPv6 internet address must be a unicast address and must not contain an imbedded IPv4 address (compatibility or mapped).

If the internet address is entered from a command line, the address must be enclosed in apostrophes.

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Local port (LCLPORT)

Specifies the local port number of the connection to end.

This is a required parameter.

1-65535
Specify the local port number of the connection to end.

Attention:

Ports 1 through 1024 are reserved for use by system-supplied TCP/IP applications. If the user specifies ports 1 through 1024, it can affect the operation of those applications.

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Remote internet address (RMTINTNETA)

Specifies the remote internet address of the connection to end. This parameter is required if PROTOCOL is *TCP.

*
The remote internet address was left unspecified when this connection was opened.

Note: If '*' is specified, an attempt will be made to end both IPv4 and IPv6 connections that have an unspecified remote internet address. To end just an IPv4 connection that has an unspecified remote internet address, specify '0.0.0.0' (the null IPv4 address) for the RMTINTNETA value. To end just an IPv6 connection that has an unspecified remote internet address, specify '::' (the null IPv6 address) for the RMTINTNETA value.

character-value
Specify the remote internet address.

An IPv4 address is specified in the form nnn.nnn.nnn.nnn, where nnn is a decimal number ranging from 0 through 255. An IPv4 address is not valid if it has a value of all binary ones or all binary zeros for the network identifier (ID) portion or the host ID portion of the address.

An IPv6 internet address is specified in the form x:x:x:x:x:x:x:x, where x is a hexidecimal number ranging from 0 through X'ffff'. "::" may be used once in the IPv6 address to indicate one or more groups of 16 bits of zeros. The "::" may be used to compress leading, imbedded, or trailing zeros in the address. An IPv6 internet address must be a unicast address and must not contain an imbedded IPv4 address (compatibility or mapped).

If the internet address is entered from a command line, the address must be enclosed in apostrophes.

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Remote port (RMTPORT)

Specifies the remote port number of the connection to end.

This parameter is required if PROTOCOL is *TCP.

*
The remote port number was left unspecified when this connection was opened.
1-65535
Specify the remote port number of the connection to end.
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Examples

Example 1: Ending an IPv4 TCP Connection

ENDTCPCNN   PROTOCOL(*TCP)  LCLINTNETA('9.5.1.109')
            LCLPORT(13054)
            RMTINTNETA('9.130.28.144')  RMTPORT(23)

This command ends the TCP connection between local port 13054 for local internet address 9.5.1.109 and remote port 23 for remote internet address 9.130.28.144. The TCP/IP protocol stack ends all activity on the connection and returns the resources to the free storage pools.

Example 2: Closing an IPv4 UDP Socket

ENDTCPCNN   PROTOCOL(*UDP)  LCLINTNETA('9.130.28.144')
            LCLPORT(596)

This command closes the UDP socket using local port 596 and local internet address 9.130.28.144. The TCP/IP protocol stack ends all activity on the connection and returns the resources to the free storage pools.

Example 3: Ending a LISTEN State TCP Socket

ENDTCPCNN   PROTOCOL(*TCP)  LCLINTNETA(*)  LCLPORT(5023)
            RMTINTNETA(*)  RMTPORT(*)

This command ends the TCP socket that is listening on local port 5023. The application that created this socket did not specify a local internet address. The socket is closed and the local port is made available for use by another application.

Example 4: Ending an IPv6 TCP Connection

ENDTCPCNN   PROTOCOL(*TCP)  LCLINTNETA('1234::5678')
            LCLPORT(13054)
            RMTINTNETA('1234::5679')  RMTPORT(23)

This command ends the TCP connection between local port 13054 for local internet address 1234::5678 and remote port 23 for remote internet address 1234::5679. The TCP/IP protocol stack ends all activity on the connection and returns the resources to the free storage pools.

Example 5: Closing an IPv6 UDP Socket

ENDTCPCNN   PROTOCOL(*UDP)  LCLINTNETA('::')
            LCLPORT(596)

This command closes the UDP socket using local port 596 and an unspecified IPv6 local internet address. The TCP/IP protocol stack ends all activity on the connection and returns the resources to the free storage pools.

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Error messages

*ESCAPE Messages

TCP2670
Not able to complete request. TCP/IP services are not available.
TCP3B01
Not able to end TCP connection &7 &4, &8 &6.
TCP3B02
Not able to close UDP socket &7 &4.
TCP9999
Internal system error in program &1.
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