Using AutoIP

AutoIP is a module that you must mount into io-pkt*. It's used for quick configuration of hosts on a small network.

AutoIP assigns a link-local IP address from the 169.254/16 network to its interface if no other host is using this address. The advantage of using AutoIP is that you don't need a central configuration server. The hosts negotiate among themselves which IP addresses are free to use, and monitor for conflicts.

It's common to have a host employ both DHCP and AutoIP at the same time. When the host is first connected to the network, it doesn't know if a DHCP server is present or not. If you start dhcp.client with the -a option (apply IP address as an alias), then both a link-local IP address and DHCP IP address can be assigned to your interface at the same time. If the DHCP server isn't present, dhcp.client times out, leaving the link-local IP address active. If a DHCP server becomes available later, dhcp.client can be restarted and a DHCP IP address applied without interfering with any TCP/IP connections currently using the link-local IP address.

Having both a DHCP-assigned address and a link-local address active at the same time lets you communicate with hosts that have link-local IP addresses and those that have regular IP addresses. For more information, see and dhcp.client in the Utilities Reference.