In Linux, simple knocking (fixed sequences of ports) can be done entirely in the kernel with nftables rules. Probably could even have different knock ports base

In Linux, simple knocking (fixed sequences of ports) can be done entirely in the kernel with nftables rules. Probably could even have different knock ports based on day of the week or hour or source IP. https://wiki.nftables.org/wiki-nftables/index.php/Port_knocking_example https://wiki.nftables.org/wiki-nftables/index.php/Port_knock...