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 onE.g. A server listening on127.0.0.1
, you need to specify the port on which the server listens to incoming requests whereas if your local server listens on0.0.0.0
, your server automatically listens to incoming requests on all open ports.
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.