Copyright (c) 2009 Juli Mallett <jmallett@FreeBSD.org>
Copyright (c) 2004 Markus Friedl <markus@openbsd.org>
Permission to use, copy, modify, and distribute this software for any
purpose with or without fee is hereby granted, provided that the above
copyright notice and this permission notice appear in all copies.
THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
$FreeBSD$
.Dd January 30, 2013 .Dt TCPDROP 8 .Os .Sh NAME .Nm tcpdrop .Nd drop TCP connections .Sh SYNOPSIS .Nm tcpdrop .Ar local-address .Ar local-port .Ar foreign-address .Ar foreign-port .Nm tcpdrop .Op Fl l .Fl a .Sh DESCRIPTION The .Nm command may be used to drop TCP connections from the command line.
p If .Fl a is specified then .Nm will attempt to drop all active connections. The .Fl l flag may be given to list the tcpdrop invocation to drop all active connections one at a time.
p If .Fl a is not specified then only the connection between the given local address .Ar local-address , port .Ar local-port , and the foreign address .Ar foreign-address , port .Ar foreign-port , will be dropped.
p Addresses and ports may be specified by name or numeric value. Both IPv4 and IPv6 address formats are supported.
p The addresses and ports may be separated by periods or colons instead of spaces. .Sh EXIT STATUS .Ex -std .Sh EXAMPLES If a connection to .Xr httpd 8 is causing congestion on a network link, one can drop the TCP session in charge: d -literal -offset indent # sockstat -c | grep httpd www httpd 16525 3 tcp4 \e 192.168.5.41:80 192.168.5.1:26747 .Ed
p The following command will drop the connection: d -literal -offset indent # tcpdrop 192.168.5.41 80 192.168.5.1 26747 .Ed
p The following command will drop all connections but those to or from port 22, the port used by .Xr sshd 8 : d -literal -offset indent # tcpdrop -l -a | grep -vw 22 | sh .Ed .Sh SEE ALSO .Xr netstat 1 , .Xr sockstat 1 .Sh AUTHORS .An Markus Friedl Aq markus@openbsd.org .An Juli Mallett Aq jmallett@FreeBSD.org