This destination is expressed as 0.0.0.0 / 0 in CIDR notation. In the context of routing tables, a network destination of 0.0.0.0 is used with a network mask of 0 to depict the default route as a destination subnet. If a host has two IP addresses, 192.168.1.1 and 10.1.2.1, and a server running on the host is configured to listen on 0.0.0.0, it will be reachable at both of those IP addresses. In the context of servers, 0.0.0.0 can mean "all IPv4 addresses on the local machine".