System and method of assigning and reclaiming static addresses through the dynamic host configuration protocol
First Claim
1. A method of reclaiming static IP addresses from a client machine connected to a network utilizing a dynamic host configuration protocol (DHCP) server, comprising:
- establishing a security association with the client machine;
sending a DHCP RECLAIM command to the client machine having the static IP address to be reclaimed; and
setting a state of the static IP address to be reclaimed to FREE.
1 Assignment
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Accused Products
Abstract
Presented is a system and method for providing centralized address management of static IP addresses through the dynamic host control protocol. Static or permanent IP addresses are those addresses assigned by DHCP having an infinite lease time. The assignment of such static IP addresses follows the conventional DHCP mechanism for the assignment of other IP addresses. However, the centralized reclamation of a statically or permanently assigned IP address by a network administrator through the DHCP server presents novel aspects of the invention heretofore unknown. Specifically, through the system and method of the present invention, the DHCP server is capable of reclaiming at any point in time, a statically or permanently assigned IP address by transmitting a DHCP RECLAIM command to the DHCP client, or through its relay agent. In the normal situation, the DHCP client acknowledges the RECLAIM command, allowing the IP address to be placed in the FREE state. If, however, the DHCP client does not respond or the responses are not received by the DHCP server, the DHCP server marks the state of the IP address as DEPRECATED. The state of the IP address will be changed from DEPRECATED to FREE once a number of retries of the RECLAIM process has been completed, or a maximum period of time has passed. Security mechanisms to prevent a malicious attacker from reclaiming static IP address from DHCP clients are also presented.
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Citations
20 Claims
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1. A method of reclaiming static IP addresses from a client machine connected to a network utilizing a dynamic host configuration protocol (DHCP) server, comprising:
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establishing a security association with the client machine;
sending a DHCP RECLAIM command to the client machine having the static IP address to be reclaimed; and
setting a state of the static IP address to be reclaimed to FREE. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of relinquishing a static IP address, comprising:
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establishing a security association with a dynamic host configuration protocol (DHCP) server;
receiving a DHCP RECLAIM command;
entering the DHCP initialization (INIT) state to obtain a new IP address; and
sending an acknowledgment (ACK) of the DHCP RECLAIM command. - View Dependent Claims (13, 14, 15, 16)
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17. The method of claim 15, further comprising:
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entering a DHCP INIT state in response to determining the current IP address is marked for removal; and
entering a DHCP INIT_REBOOT state in response to determining the current IP address is not marked for removal. - View Dependent Claims (18, 19, 20)
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17-1. A method of connecting to a network to achieve an IP address through DHCP, comprising:
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establishing a security association with a dynamic host configuration protocol (DHCP) server;
determining whether a current IP address exists;
determining whether the current IP address is marked for removal;
entering a DHCP INIT state in response to determining there is no current IP address;
entering a DHCP INIT state in response to determining the current IP address is marked for removal; and
entering a DHCP INIT_REBOOT state in response to determining the current IP address is not marked for removal.
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Specification