1.\" $OpenBSD: tcpdrop.8,v 1.5 2004/05/24 13:57:31 jmc Exp $ 2.\" 3.\" Copyright (c) 2009 Juli Mallett <jmallett@FreeBSD.org> 4.\" Copyright (c) 2004 Markus Friedl <markus@openbsd.org> 5.\" 6.\" Permission to use, copy, modify, and distribute this software for any 7.\" purpose with or without fee is hereby granted, provided that the above 8.\" copyright notice and this permission notice appear in all copies. 9.\" 10.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 11.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 12.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 13.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 14.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 15.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 16.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 17.\" 18.\" $FreeBSD$ 19.\" 20.Dd January 30, 2013 21.Dt TCPDROP 8 22.Os 23.Sh NAME 24.Nm tcpdrop 25.Nd drop TCP connections 26.Sh SYNOPSIS 27.Nm tcpdrop 28.Ar local-address 29.Ar local-port 30.Ar foreign-address 31.Ar foreign-port 32.Nm tcpdrop 33.Op Fl l 34.Fl a 35.Sh DESCRIPTION 36The 37.Nm 38command may be used to drop TCP connections from the command line. 39.Pp 40If 41.Fl a 42is specified then 43.Nm 44will attempt to drop all active connections. 45The 46.Fl l 47flag may be given to list the tcpdrop invocation to drop all active 48connections one at a time. 49.Pp 50If 51.Fl a 52is not specified then only the connection between the given local 53address 54.Ar local-address , 55port 56.Ar local-port , 57and the foreign address 58.Ar foreign-address , 59port 60.Ar foreign-port , 61will be dropped. 62.Pp 63Addresses and ports may be specified by name or numeric value. 64Both IPv4 and IPv6 address formats are supported. 65.Pp 66The addresses and ports may be separated by periods or colons 67instead of spaces. 68.Sh EXIT STATUS 69.Ex -std 70.Sh EXAMPLES 71If a connection to 72.Xr httpd 8 73is causing congestion on a network link, one can drop the TCP session 74in charge: 75.Bd -literal -offset indent 76# sockstat -c | grep httpd 77www httpd 16525 3 tcp4 \e 78 192.168.5.41:80 192.168.5.1:26747 79.Ed 80.Pp 81The following command will drop the connection: 82.Bd -literal -offset indent 83# tcpdrop 192.168.5.41 80 192.168.5.1 26747 84.Ed 85.Pp 86The following command will drop all connections but those to or from 87port 22, the port used by 88.Xr sshd 8 : 89.Bd -literal -offset indent 90# tcpdrop -l -a | grep -vw 22 | sh 91.Ed 92.Sh SEE ALSO 93.Xr netstat 1 , 94.Xr sockstat 1 95.Sh AUTHORS 96.An Markus Friedl Aq markus@openbsd.org 97.An Juli Mallett Aq jmallett@FreeBSD.org 98