knockd(1)                                                            knockd(1)

NAME
       knock - port-knock client

SYNOPSIS
       knock [options] <host> <port[:proto]> [port[:proto]] ...

DESCRIPTION
       knock is a port-knock client.  It sends TCP/UDP packets to each
       specified port on host, creating a special knock sequence on the
       listening server (see the knockd manpage for more info on this).

OPTIONS
       -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.

       -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.

       -4, --ipv4 <version>
              Force usage of IPv4.

       -6, --ipv6 <version>
              Force usage of IPv6.

       -v, --verbose
              Output verbose status messages.

       -V, --version
              Display the version.

       -h, --help
              Syntax help.

EXAMPLES
       knock myserver.example.com 123:tcp 456:udp 789:tcp
       knock -u myserver.example.com 8284 4721 18592 42912

SEE ALSO
       knockd is the accompanying port-knock server.

AUTHOR
       Judd Vinet <jvinet@zeroflux.org>

knockd 0.8                      April 22, 2021                       knockd(1)