.TH knock 1 "June 26, 2005" "knockd 0.7" ""
.SH NAME
knock \- port-knock client
.SH SYNOPSIS
\fBknock [options] <host> <port[:proto]> [port[:proto]] ...\fP
.SH DESCRIPTION
\fBknock\fP is a \fIport-knock\fP client.  It sends TCP/UDP packets
to each specified \fIport\fP on \fIhost\fP, creating a special knock
sequence on the listening server (see the \fBknockd\fP manpage for more
info on this).
.SH OPTIONS
.TP
.B "\-u, \-\-udp"
Make all port hits use UDP (default is TCP).
If you want each port to use a different protocol (TCP or UDP), then you
can specify the protocol on a per-port basis.  See the example below.
.TP
.B "\-d <t>, \-\-delay <t>"
Wait <t> milliseconds between each port hit.  This can be used in situations
where a router mistakes your stream of SYN packets as a port scan and blocks
them.  If the packet rate is slowed with --delay, then the router should let
the packets through.
.TP
.B "\-v, \-\-verbose"
Output verbose status messages.
.TP
.B "\-V, \-\-version"
Display the version.
.TP
.B "\-h, \-\-help"
Syntax help.
.SH EXAMPLES
.nf
knock myserver.example.com 123:tcp 456:udp 789:tcp
knock -u myserver.example.com 8284 4721 18592 42912
.fi
.SH SEE ALSO
\fBknockd\fP is the accompanying port-knock server.
.SH AUTHOR
.nf
Judd Vinet <jvinet@zeroflux.org>
.fi