RFC 3203 (rfc3203) - Page 2 of 6
DHCP reconfigure extension
Alternative Format: Original Text Document
RFC 3203 DHCP reconfigure extension December 2001 2.1 Terminology DHCP client : host to be reconfigured using DHCP. DHCP server : server which configured the DHCP client. 2.2 Force renew procedures The DHCP server sends a unicast FORCERENEW message to the client. Upon receipt of the unicast FORCERENEW message, the client will change its state to the RENEW state, and will then try to renew its lease according to normal DHCP procedures. If the server wants to assign a new IP address to the client, it will reply to the DHCP REQUEST with a DHCP NAK. The client will then go back to the init state and broadcast a DHCP DISCOVER message. The server can now assign a new IP address to the client by replying with a DHCP OFFER. If the FORCERENEW message is lost, the DHCP server will not receive a DHCP REQUEST from the client and it should retransmit the FORCERENEW message using an exponential backoff algorithm. Depending on the bandwidth of the network between server and client, the server should choose a delay. This delay grows exponentially as retransmissions fail. The amount of retransmissions should be limited. The procedures described above assume the server to send a unicast FORCERENEW message to the client. Receipt of a multicast FORCERENEW message by the client should be silently discarded. It can be that a client has obtained a network address through some other means (e.g., manual configuration) and has used a DHCP INFORM request to obtain other local configuration parameters. Such clients should respond to the receipt of a unicast FORCERENEW message with a new DHCP INFORM request so as to obtain a potential new set of local configuration parameters. Note that the usage of these procedures are limited to the set of options that are eligible for configuration by DHCP and should not override manually configured parameters. Note further that usage of the FORCERENEW message to reconfigure a client address or local configuration parameters can lead to the interruption of active sessions, and that as such these procedures should be used in controlled circumstances. T'Joens, et al. Standards Track
