What is the difference between 127.0.0.1 and 0.0.0.0?

  • binding 127.0.0.1 means listen to loopback interface

  • Process bound to 127.0.0.1 can only be accessed by other programs from the same machine

  • binding to 0.0.0.0 means listen to all interfaces ( e.g. all network interfaces connected to the machine )

  • on Mac 27.0.0.1 /32 is bound to loopback

  • on Windows 127.0.0.0 /8 is bound to loopback

Source: 0.0.0.0 vs 127.0.0.1