knock1
Port-knock client
Usage
knock [options]
<host>
<port
[:proto]
>
[port
[:proto]] ...
Overview
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
Releases
12 releases since Debian 3.1 (Sarge); the text changed 3 times.
--delay since Debian 9 (Stretch);
--ipv4 since Debian 12 (Bookworm);
--ipv6 since Debian 12 (Bookworm);
-4 since Debian 12 (Bookworm);
-6 since Debian 12 (Bookworm);
-d since Debian 9 (Stretch).