Automatic Private IP Addressing (APIPA) allows a Windows host to self-configure an IPv4 address and subnet mask when Dynamic Host Configuration Protocol (DHCP) is unavailable. APIPA uses an address block range between 169.254.0.0 and 169.254.255.255. APIPA-assigned addresses are valid only for communications within a network segment that a given host is connected to (a host with APIPA-assigned address cannot connect to the Internet).