It seems that Rails and Django can both start up the server binding to an IP, either
0.0.0.0, 127.0.0.1, or 192.168.1.2 <-- the last one is my local IP
are there other choices? It seems that 0.0.0.0 and 192.168.1.2 can let a Virtual PC on the same machine access this website, while 127.0.0.1 cannot.
However, if it is just the same notebook, using localhost:3000 (for Rails), then it doesn’t matter. But either case, 0.0.0.0:3000 won’t work.
How does it work? What are the meanings of using 0.0.0.0 vs 127.0.0.1 vs 192.168.1.2?
Binding to 0.0.0.0 means to listen to all interfaces.
Binding to 127.0.0.1 means to listen to the loopback interface.