Talk:Port knocking

message: Step 1
(A) Client cannot connect to application listening on port n; 
(B) Client cannot establish connection to any port.
Step 2
(1,2,3,4) Client tries to connect to a well-defined set of ports in sequence by sending certain packets; Client has prior knowledge of the port knocking daemon and its configuration, but receives no acknowledgement during this phase because firewall rules preclude any response.
Step 3
(A) Server process (a port knocking daemon) intercepts connection attempts and interprets (decrypts and decodes) them as comprising an authentic "port knock"; server carries out specific task based on content of port knock, such as opening port n to the client.
Step 4
(A) Client connects to port n and authenticates using application’s regular mechanism.
</blockquote>
This has already been described in the text above.  No need to write this twice.
The 'benefits' section should also be reworked and shortened, and the article lacks of some criticism, think of the reliability in slow networks with packet loss, or DoS attacks agains knock-protected services (e.g., Debian bug ).  I will look at it when i have more time. --Dc12 (talk) 22:26, 11 December 2007 (UTC)
thread_title: How Port knocking works in theory

message: In my opinion there are too many irrelevant links. ¿Is it that useful to link a 7-line article from slashdot? There are also links to 7 different implementations. It seems that 5 of them are no longer maintained by their authors (Fwknop and the netfilter module are the only active developments). 
I suggest removing most of those links. I keep a list of resources about Port Knocking and Single Packet Authorization. That includes references to papers, magazine articles, implementations, presentations, etc. I have no interest on linking my own implementation but I honestly think it would be useful to link that list of references. Check it out at http://www.aldabaknocking.com/?q=portknocking and let me know what you think. If nobody complains I will remove the following links in a couple of days:
*A Linux IP Tables implementation of port knocking. 
*Slashdot "Port Knocking" For Added Security
*A Windows implementation of port knocking: KnockKnock
*A simple implementation of port knocking.
and I will add this one:
List of resources about PK and SPA (papers, implementations, presentations...)
Luis Martin.
PS: Please keep in mind that the link I intend to add is from my own website. I want to make it clear so nobody thinks I'm trying to silently introduce spam.  —Preceding unsigned comment added by Luismgarcia (talk • contribs) 16:24, 28 February 2008 (UTC)
thread_title:  Link Section 

message: If there is a sequence of 3 packets for port knocking, there are 655353 possibilities. Ie. not 4. --Milan Kerslager (talk) 19:33, 27 May 2008 (UTC)
thread_title:  Incorrent number of packets 

message: While this technique for securing access to remote network daemons has not been widely adopted by the security community, it has been integrated in newer rootkits.
There does not seem to be any citation to back this up, does anyone know of any? Hogan (talk) 17:55, 23 December 2010 (UTC)
thread_title:  rootkits 

message: There are numerous components and processes in a system (and external to it, also) which must all work properly in order for that system to stay reachable.
A port knocking deamon is a completely trivial piece of the whole puzzle.
If you can't rely on such a thing to stay up, maybe the system is not very stable as a whole.
And since this Disadvantages section acknowledges in its conclusion that this trivial piece of software can be monitored by a watchdog, it erodes whatever point it tries to make at the outset.
192.139.122.42 (talk) 18:57, 16 April 2012 (UTC)
thread_title:  Disadvantages section is overstated to the point of being nonsense 

message: "That equates to a maximum of 65536^3 packets in order to obtain and detect a single successful opening, in the worst case scenario"
This is incorrect, or at least unclear, since attempts can overlap. For example, trying the combinations 1,2,3 and 2,3,1 would require 4 packets (1,2,3,1), not 6 (1,2,3,2,3,1).  — Preceding unsigned comment added by Zxenon (talk • contribs) 22:46, 21 July 2012 (UTC)
thread_title:  Brute force inaccuracy 

message: Single Packet Authorization currently redirect here. However, I don't think it is port knocking as the packet is actually an encrypted UDP payload that needs to be verified. In addition, the protocol can be used to specify ports and destinations, thus it is closer to UPnP in application. --Voidvector (talk) 03:36, 2 September 2017 (UTC)
thread_title:  Single Packet Authorization