Patent ID: 7747751

Claim:
A method for IP address allocation, comprising: periodically selecting, by a dynamic host configuration protocol server, a predefined number of validated IP addresses from unused IP addresses of the dynamic host configuration protocol server, said validated IP addresses being checked including via an address resolution protocol for existing use in a subnet; and allocating, by the dynamic host configuration protocol server, an IP address from selected validated IP addresses of the dynamic host configuration protocol server, when a client applies for an IP address, the client directly using the IP address allocated by the dynamic host configuration protocol server; establishing, by the dynamic host configuration protocol server, an unused IP address pool and a usable IP address pool; periodically retaining, based on IP addresses in the unused IP address pool, a predefined number of validated IP addresses in the usable IP address pool; periodically checking, by the dynamic host configuration protocol server, a number of IP addresses in the usable IP address pool; selecting and validating an unused IP address from the unused IP address pool, when the number of IP addresses in the usable IP address pool is smaller than the predefined number; and moving the unused IP address, after said selecting and validating, from the unused IP address pool to the usable IP address pool.