INADDR_ANY
            Note: does not return a number, but a packed string.
 
            Returns the 4-byte wildcard ip address which
            specifies any of the hosts ip addresses. (A
            particular machine can have more than one ip address,
            each address corresponding to a particular network
            interface. This wildcard address allows you to bind
            to all of them simultaneously.)  Normally equivalent
            to inet_aton('0.0.0.0').