Method and system for recovering DHCP data

摘要

A system in which a DHCP server executes a recovery routine after detecting a corrupted IP address state database. The routine determines whether an IP address is assigned to a DHCP client by querying an IP address/port reserved for DHCP clients. If the response suggests the absence of a DHCP client, the address is marked as BAD. If the response suggests the presence of a DHCP client, the IP database is updated appropriately. The query may comprise sending a TCP/IP packet to the IP address and port and monitoring for an ICMP error message. In another embodiment requiring a protocol extension, the DHCP server issues a DHCP supported query to each IP address that responds to a ping command. The DHCP clients supporting this protocol extension will respond to the query by returning all of the DHCP configuration information that was acquired before the IP address state database crashed.