Method and system for preventing unauthorized server interference in an internet protocol network

1. A method for preventing unauthorized dynamic host configuration servers from responding to client configuration requests in an Internet Protocol (IP) network, said method comprising the steps of:

broadcasting host configuration requests from a server checker client;

receiving configuration offer messages from one or more dynamic host configuration servers, said configuration offer messages delivered to the server checker client responsive to the broadcast host configuration requests;

detecting an unauthorized dynamic host configuration server within said IP network in accordance with server identification data within the configuration offer messages; and

responsive to said detecting step, unicasting host configuration requests from said server checker client to said unauthorized dynamic configuration server such that said unauthorized dynamic host configuration server is unable to respond to configuration requests from network clients.

2. The method of claim 1 , said unicasting host configuration requests comprising unicasting a plurality of IP address renewal requests to said unauthorized dynamic host configuration server.

3. The method of claim 2 wherein each IP address renewal request includes:

a client medium access control (MAC) address that is not included within a range of valid MAC addresses utilized within the IP network.

4. The method of claim 2 , wherein each IP address renewal request includes a client IP address that is not included within a range of valid IP addressed utilized in the IP network.

5. The method of claim 1 , wherein said checker client includes a server table having a list of authorized dynamic host configuration servers, and wherein said step of detecting an unauthorized dynamic host configuration server further comprises

comparing a server identifier included in each configuration offer message with authorized server identification data in the server table.

6. The method of claim 5 wherein said comparing a server identifier included in each configuration offer message with authorized server identification data in the server table further comprises the retrieving an IP address from each configuration offer message.

7. The method of claim 5 , wherein said server table includes an IP address for each authorized dynamic host configuration server.

8. A system for preventing unauthorized dynamic host configuration servers from responding to client configuration requests in an Internet Protocol (IP) network, said system comprising:

processing means for broadcasting host configuration requests from a server checker client;

processing means for receiving configuration offer messages from one or more dynamic host configuration servers, said configuration offer messages delivered to the server checker client responsive to the broadcast host configuration requests;

processing means for detecting an unauthorized dynamic host configuration server within said IP network in accordance with server identification data within the configuration offer messages; and

processing means, responsive to detecting an unauthorized dynamic host configuration server, for unicasting host configuration requests from said server checker client to said unauthorized dynamic configuration server such that said unauthorized dynamic host configuration server is unable to respond to configuration requests from network clients.

9. The system of claim 8 , said processing means for unicasting host configuration requests comprising processing means for unicasting a plurality of IP address renewal requests to said unauthorized dynamic host configuration server.

10. The system of claim 9 wherein each IP address renewal request includes:

a client medium access control (MAC) address that is not included within a range of valid MAC addresses utilized within the IP networks.

11. The system of claim 9 , wherein each IP address renewal request includes a client IP address that is not included within a range of valid IP addressed utilized in the IP network.

12. The system of claim 8 , wherein said checker client includes a server table having a list of authorized dynamic host configuration servers, and wherein said processing means for detecting an unauthorized dynamic host configuration server further comprises

processing means for comparing a server identifier included in each configuration offer message with authorized server identification data in the server table.

13. The system of claim 12 , wherein said processing means for comparing a server identifier included in each configuration offer message with authorized server identification data in the server table further comprises processing means for retrieving an IP address from each configuration offer message.

14. The system of claim 12 , wherein said server table includes an IP address for each authorized dynamic host configuration server.

15. A program product for preventing unauthorized dynamic host configuration servers from responding to client configuration requests in an Internet Protocol (IP) network, said program product comprising:

instruction means for broadcasting host configuration requests from a server checker client;

instruction means for processing configuration offer messages received from one or more dynamic host configuration servers, said configuration offer messages delivered to the server checker client responsive to the broadcast host configuration requests;

instruction means for detecting an unauthorized dynamic host configuration server within said IP network in accordance with server identification data within the configuration offer messages; and

instruction means, responsive to said detecting, for unicasting host configuration requests for said server checker client to said unauthorized dynamic configuration server such that said unauthorized dynamic host configuration server is unable to respond to configuration requests from network clients.

16. The program product of claim 15 , said instruction means for unicasting host configuration requests comprising instruction means for unicasting a plurality of IP address renewal requests.

17. The program product of claim 16 , wherein each IP address renewal request includes:

a client medium access control (MAC) address that is not included within a range of valid MAC addresses utilized within the IP networks.

18. The program product of claim 16 wherein each IP address renewal request includes a client IP address that is not included within a range of valid IP addressed utilized in the IP network.

19. The program product of claim 15 wherein said checker client includes a server table having a list of authorized dynamic host configuration servers, and wherein said instruction means for detecting an unauthorized dynamic host configuration server further comprises:

comparing a server identifier included in each configuration offer message with authorized server identification data in the server table.

20. The program product of claim 19 , wherein said instruction means for comparing a server identifier included in each configuration offer message with authorized server identification data in the server table further comprises instructions means for retrieving an IP address from each configuration offer message.

21. The program product of claim 19 wherein said server table includes an IP address for each authorized dynamic host configuration server.