(pôrt nok´ing) (n.) A method of establishing a connection to a secured network or computer within a network that does not have an open port. A remote device sends a series of series of connection attempts, in the form of packets, to the computer’s closed ports, and the attempts are silently ignored but logged by the firewall. When the remote device has established the predetermined sequence of port connection attempts, a daemontriggers a port to open, and the network connection is established. This security method is analogous to knowing a “secret knock,” and only people who know the proper knock sequence will be allowed access. An advantage of using a port knocking technique is that a malicious hacker cannot detect if a device is listening for port knocks.
Other forms: port knock(n.), (v.)
HOWTO: Port Knocking An introduction to how trusted users can manipulate firewall rules to transmit information across closed ports.
