knockd(1) knockd(1) (NAME) knock - (port-knock) (SYNOPSIS) knock [options] [port[:proto]] ... (DESCRIPTION) knock port-knock . TCP/UDP port host (knock) ( knockd ). (OPTIONS) -u, --udp UDP ( TCP ). (TCP UDP) . . -d , --delay . () SYN (Port Scan) . --delay . -4, --ipv4 IPv4. -6, --ipv6 IPv6. -v, --verbose . -V, --version . -h, --help . (EXAMPLES) knock myserver.example.com 123:tcp 456:udp 789:tcp knock -u myserver.example.com 8284 4721 18592 42912 (SEE ALSO) knockd . (AUTHOR) Judd Vinet knockd 0.8 April 22, 2021 knockd(1)