8 lines
546 B
Text
8 lines
546 B
Text
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knockd is a port-knock server. It listens to all traffic on an ethernet (or PPP)
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interface, looking for special "knock" sequences of port-hits. A client makes
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these port-hits by sending a TCP (or UDP) packet to a port on the server. This
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port need not be open - since knockd listens at the link-layer level, it sees
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all traffic even if it's destined for a closed port. When the server detects
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a specific sequence of port-hits, it runs a command defined in its configuration
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file. This can be used to open up holes in a firewall for quick access.
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