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Good Morning,

I have a non issue that I am just curious how its working. So I have a wireless doorbell that I built. It works using the gpiod and remote gpio. So I have a chime unit that I built with a Python script to play MP3s. I'm running the systemctl enable and systemctl start commands from the chime raspberry pi. The chime has a static ip that is assigned. I have a second raspberry pi hooked up with a button that is used as the front doorbell. I have a python script that when run waits for that button press. It then finds that static IP and signals a particular pin. In this case pin 18 and runs the program. Because this is done through IP I assumed that this was all working through my wifi. However, my local ISP is experiencing an outage and my internet has been down for three days yet the doorbell still works. Is the chime sending this information through a protocol that does not need the internet and since the IP is static it isn't changing? Honestly I love the idea of being able to build something with remote control functionality but I would love to know how its working.

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    IP doesn't have to go through the internet. It's staying within your LAN. – Mark Smith Apr 26 at 17:17
  • That makes sense I just figured it did I guess. thank you – user92521 Apr 26 at 17:56
  • Since you have a non issue, I will give you a problem to fix! :-) Look into using a nodeMCU as the door button. There is no reason to have a full linux box just to have a button and send a signal over wifi. I realize this changes your whole setup, but just a thought. – Chad G Apr 26 at 18:33
  • here is another problem to fix ... lol .... please change the title of you post so that it about your actual question .... something like why is my wifi operational when my ISP is down? – jsotola Apr 27 at 17:46
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The Internet is a network of networks. You have local networks which connect to a wider network via a gateway. Both the local networks and the wider networks run over IP (even though the local networks aren't strictly "the internet").

When a node on a network sends an IP packet it is pushed to the nearest gateway which figures out where to send it next based on the destination IP address. If that address is in the local network, then the gateway sends it straight there. If it's in the wider network then the gateway sends it out to the wider network.

Your ISP only provides you a connection to the wider network. The local network is all you!

Whether your network uses static IP address or not is irrelevant - the nodes and gateways in your local network still need to be able to find each other. They do that using the IP protocol, which doesn't require the Internet.

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