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And to save other folks a search, this is pretty awesome: https://linux.die.net/man/1/knockd
If someone intercepts the traffic to my server, they could see the knock sequence and re-use it. Is there any way to get knockd to use a google authenticator-like sequence of port knocks?
I lost my fob. So I took my intercom apart and wired a band pass filter circuit between the buzzer input and actuator output. If you pressed my buzzer with the right steady pattern, it would automatically let you in.
It worked great and I didn’t buy a replacement fob.
A few months later I started getting woken up by someone buzzing my buzzer. They would always scurry in before I could open my door to see who it was.
Turns out my upstairs neighbor saw my shenanigans a few times and started freeloading off my invention. Honestly amazed he/she reverse engineered what was going on!
Needless to say, I bought a new fob.
Port knocking is great theatre but not much good for anything else. I guess it can keep logs clear feom some drive by script kiddies.
I would think that if you are going to disparage it, you would at least give one example of why it's unnecessary.
I implemented a physical port-knocking daemon, once. I lived in a block of flats — you needed an expensive fob to open the outer gate, and it didn’t even work reliably. I lost my fob. So I took my intercom apart and wired a band pass filter circuit between the buzzer input and actuator output. If you pressed my buzzer with the right steady pattern, it would automatically let you in. It worked great and I didn’t buy a…
I understand the key fob/card concept for access purposes, but have never heard of an “intercom” in the context of home/apartment/etc security.
Take a look at fwknop for the implementation. The only issue with it is there’s no easy install for pfsense.
I've been in this business for a long, long time and have come across all manner of innovations regarding network security. Port knocking (which I think I learned about first at defcon ... perhaps 18 years ago ?) stands out as one of the very few things that made my network(s) substantially safer at nearly zero cost. I love, and continue to love, both the idea and the implementation. Pay no attention to the nay-sayer…
any tips or where one would get best practice for configuring/setting up/using knockd? I wrote up how having a server on the internet is scary now ( http://redgreenrepeat.com/2020/03/20/why-you-should-secure-y... ) and how to protect it ( http://redgreenrepeat.com/2020/04/10/how-to-secure-your-serv... ) One thing I didn't get into more was port knocking/knockd as there were not many resources for it. I'd love to lear…
https://www.howtogeek.com/105693/how-to-knock-into-your-netw...
I implemented a physical port-knocking daemon, once. I lived in a block of flats — you needed an expensive fob to open the outer gate, and it didn’t even work reliably. I lost my fob. So I took my intercom apart and wired a band pass filter circuit between the buzzer input and actuator output. If you pressed my buzzer with the right steady pattern, it would automatically let you in. It worked great and I didn’t buy a…
I enjoyed your story, but can you please elaborate on what your intercom is / was for? I understand the key fob/card concept for access purposes, but have never heard of an “intercom” in the context of home/apartment/etc security.
I implemented a physical port-knocking daemon, once. I lived in a block of flats — you needed an expensive fob to open the outer gate, and it didn’t even work reliably. I lost my fob. So I took my intercom apart and wired a band pass filter circuit between the buzzer input and actuator output. If you pressed my buzzer with the right steady pattern, it would automatically let you in. It worked great and I didn’t buy a…
I enjoyed your story, but can you please elaborate on what your intercom is / was for? I understand the key fob/card concept for access purposes, but have never heard of an “intercom” in the context of home/apartment/etc security.