How DHCP Client Manages Network Configuration Information

After the information packet is obtained from a DHCP server, dhcpagent configures the network interface and brings it up, controlling the interface for the duration of the lease time for the IP address. dhcpagent maintains the configuration data in an internal table held in memory. The system startup scripts use the dhcpinfo command to extract configuration option values from the dhcpagent's table. The values are used in configuring the system and becoming part of the network.

The agent waits passively until a set period of time elapses, usually half the lease time, and then requests an extension of the lease from a DHCP server. If dhcpagent finds that the interface is down or the IP address has changed, it does not control the interface until it is instructed by ifconfig to do so. If dhcpagent finds that the interface is up and the IP address hasn't changed, it sends a request to the server for a lease renewal. If the lease cannot be renewed, dhcpagent takes the interface down at the end of the lease time.