What does ip address 0.0.0.0 mean?
The first time I saw that addres I was a bit confused. I used to think that
127.0.0.1 was the only way to refer to your local machine. Turns out,
0.0.0.0 is another way to do this, but with a subtle difference.
If your local server listens on
127.0.0.1, you need to specify the port on which the server listens to incoming requests whereas if your local server listens on
0.0.0.0, your server automatically listens to incoming requests on all open ports.
A server listening on
127.0.0.1:8000 would listen to requests to port 8000 but a server listening on
0.0.0.1 would listen to requests on any open port on the system.
One use case for using
0.0.0.0 would be if you are using a virtualization layer such as docker where each container runs a single service and the port that it receives requests from can be configured externally.