knockd is a port-knock server. It listens to all traffic on an ethernet (or PPP) interface, looking for special knock sequences of port-hits. A client makes these port-hits by sending a TCP (or UDP) packet to a port on the server. This port need not be open -- since knockd listens at the link-layer level, it sees all traffic even if it's destined for a closed port. When the server detects a specific sequence of port-hits, it runs a command defined in its configuration file. This can be used to open up holes in a firewall for quick access.
knockd is a port-knock server. It listens to all traffic on an ethernet (or PPP) interface, looking for special knock sequences of port-hits. A client makes these port-hits by sending a TCP (or UDP) packet to a port on the server. This port need not be open -- since knockd listens at the link-layer level, it sees all traffic even if it's destined for a closed port. When the server detects a specific sequence of port-hits, it runs a command defined in its configuration file. This can be used to open up holes in a firewall for quick access.
To install knock, run the following command in macOS terminal (Applications->Utilities->Terminal)
sudo port install knock
To see what files were installed by knock, run:
port contents knock
To later upgrade knock, run:
sudo port selfupdate && sudo port upgrade knock
Reporting an issue on MacPorts Trac
The MacPorts Project uses a system called Trac to file tickets to report bugs and enhancement requests.
Though anyone may search Trac for tickets, you must have a GitHub account in order to login to Trac to create tickets.