IP address allocation method, network appliance and authentication server

The invention provides an IP address allocating method, a network device, an authentication server and an address allocating server, belonging to data communication technologic field. The invention sets the IP address authentication and distribution of privilege rules, and through the distribution of network equipment in the address request message to carry the privilege of labeling, the distribution of privileges for the privilege of the user IP address, does not require a change in the original network topology, only by the original equipment simple software upgrade or configuration changes, you can achieve the privileges reserved for the privileged user IP addresses, the simplified network management.