NAT Server Options
- If you use APIPA to automatically configure computers on the private network, you must: manually select the IP address of the private network interface for the NAT server from the range of APIPA addresses.
- If the NAT client computers on the private network are configured to automatically obtain their Transmission Control Protocol/Internet Protocol (TCP/IP) configuration...: then the NAT server configures the TCP/IP options when the computers on the private network are started.
- If the private network consists of a single, nonrouted subnet and other private network servers do not provide DNS name resolution: then you must include the DNS name resolution feature of NAT in your solution.
- If the client computers on the private network use DHCP for IP configuration...: then you must include the IP address assignment feature of NAT in your solution.
A feature of Microsoft Windows, APIPA is a DHCP failover mechanism for local networks.
With APIPA, DHCP clients can obtain IP addresses when DHCP servers are non-functional. APIPA exists in all modern versions of Windows except Windows NT.
When a DHCP server fails, APIPA allocates IP addresses in the private range 169.254.0.1 to 169.254.255.254. Clients verify their address is unique on the network using ARP.
When the DHCP server is again able to service requests, clients update their addresses automatically.
In APIPA, all devices use the default network mask 255.255.0.0 and all reside on the same subnet.
APIPA is enabled on all DHCP clients in Windows unless the computer's Registry is modified to disable it. APIPA can be enabled on individual network adapters.