&gt; Using 0.0.0.0 [instead of 127.0.0.1] is faster because you don&#x27;t have to wait for a timeout.<p>I&#x27;m not going to argue that localhost is better than 0, but that specific argument they&#x27;ve raised is incorrect. You don&#x27;t have to wait for a timeout on localhost either. It will either fail instantly due to no listening processes on that IP and port, or it will connect to whatever process you have open on that address (eg a local instance of a http daemon).