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TCPDROP(8)		  BSD System Manager's Manual		    TCPDROP(8)

NAME
     tcpdrop --	drop TCP connections

SYNOPSIS
     tcpdrop local-address local-port foreign-address foreign-port
     tcpdrop [-l] -a
     tcpdrop [-l] -S stack
     tcpdrop [-l] -s state
     tcpdrop [-l] -S stack -s state

DESCRIPTION
     The tcpdrop command may be	used to	drop TCP connections from the command
     line.

     If	-a is specified	then tcpdrop will attempt to drop all TCP connections.

     If	-S stack is specified then tcpdrop will	attempt	to drop	all connec-
     tions using the TCP stack stack.

     If	-s state is specified then tcpdrop will	attempt	to drop	all TCP	con-
     nections being in the state state.	 state is one of SYN_SENT, SYN_RCVD,
     ESTABLISHED, CLOSE_WAIT, FIN_WAIT_1, CLOSING, LAST_ACK, FIN_WAIT_2, or
     TIME_WAIT.

     If	-S stack and -s	state are specified, tcpdrop will attempt to drop all
     TCP connections being in the state	state and using	the TCP	stack stack.
     Since TCP connections in the TIME_WAIT state are not tied to any TCP
     stack, using the option -s	TIME_WAIT in combination with the -S stack op-
     tion results in tcpdrop not dropping any TCP connection.

     The -l flag may be	given in addition to the -a, -S, or -s options to list
     the tcpdrop invocation to drop all	corresponding TCP connections one at a
     time.

     If	none of	the -a,	-S, or -s options are specified	then only the connec-
     tion between the given local address local-address, port local-port, and
     the foreign address foreign-address, port foreign-port, will be dropped.

     Addresses and ports may be	specified by name or numeric value.  Both IPv4
     and IPv6 address formats are supported.

     The addresses and ports may be separated by periods or colons instead of
     spaces.

EXIT STATUS
     The tcpdrop utility exits 0 on success, and >0 if an error	occurs.

EXAMPLES
     If	a connection to	httpd(8) is causing congestion on a network link, one
     can drop the TCP session in charge:

	   # sockstat -c | grep	httpd
	   www	    httpd      16525 3	tcp4 \
		   192.168.5.41:80	192.168.5.1:26747

     The following command will	drop the connection:

	   # tcpdrop 192.168.5.41 80 192.168.5.1 26747

     The following command will	drop all connections but those to or from port
     22, the port used by sshd(8):

	   # tcpdrop -l	-a | grep -vw 22 | sh

     The following command will	drop all connections using the TCP stack fas-
     tack:

	   # tcpdrop -S	fastack

     To	drop all TCP connections in the	LAST_ACK state use:

	   # tcpdrop -s	LAST_ACK

     To	drop all TCP connections using the TCP stack fastack and being in the
     LAST_ACK state use:

	   # tcpdrop -S	fastack	-s LAST_ACK

SEE ALSO
     netstat(1), sockstat(1), tcp(4), tcp_functions(9)

AUTHORS
     Markus Friedl <markus@openbsd.org>
     Juli Mallett <jmallett@FreeBSD.org>

BSD			      September	15, 2017			   BSD
NAME | SYNOPSIS | DESCRIPTION | EXIT STATUS | EXAMPLES | SEE ALSO | AUTHORS

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