Techniques for dynamic host configuration without direct communications between client and server

• US 7,139,818 B1
• Filed: 10/04/2001
• Issued: 11/21/2006
• Est. Priority Date: 10/04/2001
• Status: Expired due to Fees

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Johnson, Richard, Kinnear, Kenneth Jr., Stapp, Mark
• Primary Examiner(s): Vu, Thong
• Application Number:
  US09/972,139
• Time in Patent Office: 1,874 Days
• Field of Search: 709/220, 709/227, 709/222, 709/238, 709/218, 709/221, 709/228, 709/226, 709/244, 709/229, 713/201, 370/401, 370/466, 370/490, 370/458, 370/356, 370/395, 370/493, 370/516, 370/352, 725/111, 455/435
• US Class Current: 709/222
• CPC Class Codes: H04L 61/5014 using dynamic host configuration protocol [DHCP] or bootstrap protocol [BOOTP]
• CPC Class Codes: H04L 61/5053 Lease time; Renewal aspects
• CPC Class Codes: H04L 61/59 using proxies for addressing
• CPC Class Codes: H04L 63/0272 Virtual private networks

Abstract

A method for providing leased network addresses for a host from a server executing on a server device is disclosed. A first request for a leased network address from the host, relayed by an intermediate device, is received. The intermediate device filters communications between the host and the server device. A response is generated for the host, by the server, which offers a leased network address for a particular period of time and includes a network address of the intermediate device. The network address of the intermediate device is provided in a portion of the response normally designated for indicating a network address of the server. By providing the address of the intermediate device in the portion of the response designated for the server address, the server causes the client to send renewal requests to the intermediate device so that a relay process on the intermediate device can properly operate on the request, without modifying the client process.

Claims

1. A method of providing leased network addresses for a host from a server, wherein communications between the host and the server device are filtered by an intermediate device, the method comprising the computer-implemented steps of:

receiving a request for a leased network address for the host from the intermediate device;

generating a response for the host offering a leased network address for a particular period of time, including inserting first data comprising a network address of the intermediate device into a portion of the response designated for indicating a network address of the server for subsequent communication from the host to the server;

sending the response to the host through the intermediate device; and

wherein the intermediate device forwards the request including second data indicating the request is directed to the intermediate device and including third data indicating services related to providing leased network addresses.

2. A method as recited in claim 1, further comprising the step of formatting the response according to a dynamic host configuration protocol (DHCP).

3. A method as recited in claim 2, wherein the portion of the response is a server identification field in a set of optional fields for the DHCP.

4. A method as recited in claim 1, wherein the request is formatted according to a dynamic host configuration protocol (DHCP).

5. A method as recited in claim 1, wherein the intermediate device prevents transmission of a particular request from the host to a particular destination network address indicated by the particular request unless the particular network address is one of a set of one or more network addresses stored by the intermediate device.

6. A method as recited in claim 5, wherein a network address of the server device is not among the set of one or more network addresses stored by the intermediate device.

7. A method as recited in claim 1, wherein the second data comprises data that indicates a broadcast from the host.

8. A method as recited in claim 1, wherein the second data comprises data that indicates a destination network address that is the network address of the intermediate device.

9. A method as recited in claim 1, wherein the third data indicates a port number associated with services related to providing leased network addresses.

10. A method as recited in claim 1, wherein the intermediate device is configured as a relay agent for a dynamic host configuration protocol (DHCP).

11. A method as recited in claim 1, further comprising the steps of:

sending a second request for extending the particular period of time for the host to the intermediate device, based on the first data; and

receiving the second request for extending the particular time for the host from the intermediate device.

12. The method as recited in claim 1, wherein the intermediate device filters requests from the host by not forwarding a particular request to the server device unless the particular request indicates a particular port associated with services related to leased network addresses.

13. A method as recited in claim 1, wherein the intermediate device filters requests from the host by redirecting a particular request to the server device.

14. A method as recited in claim 1, wherein the intermediate device filters requests from the host by inserting second data into a portion of the request designated for a relay agent.

15. The method as recited in claim 14, wherein the second data indicates an interface of the intermediate device connected to the host.

16. The method as recited in claim 14, wherein the second data indicates a particular virtual private network to which the host belongs.

17. A computer-readable medium carrying one or more sequences of instructions for providing leased network addresses for a host from a server, wherein communications between the host and the server are filtered by an intermediate device, which instructions, when executed by one or more processors, cause the one or more processors to carry out the steps of:

receiving a request for a leased network address for the host from the intermediate device;

generating a response for the host offering a leased network address for a particular period of time, including inserting first data comprising a network address of the intermediate device into a portion of the response designated for indicating a network address of the server for subsequent communication from the host to the server;

sending the response to the host through the intermediate device; and

wherein the intermediate device forwards the request including second data indicating the request is directed to the intermediate device and including third data indicating services related to providing leased network addresses.

18. An apparatus for providing leased network addresses for a host from a server, wherein communications between the host and the server are filtered by an intermediate device, comprising:

means for receiving a request for a leased network address for the host from the intermediate device;

means for generating a response for the host offering a leased network address for a particular period of time, including inserting first data comprising a network address of the intermediate device into a portion of the response designated for indicating a network address of the server for subsequent communication from the host to the server;

means for sending the response to the host through the intermediate device; and

wherein the intermediate device forwards the request including second data indicating the request is directed to the intermediate device and including third data indicating services related to providing leased network addresses.

19. An apparatus as recited in claim 18, further comprising means for formatting the response according to a dynamic host configuration protocol (DHCP).

20. An apparatus as recited in claim 19, wherein the portion of the response is a server identification field in a set of optional fields for the DHCP.

21. An apparatus as recited in claim 18, wherein the request is formatted according to a dynamic host configuration protocol (DHCP).

22. An apparatus as recited in claim 18, wherein the intermediate device prevents transmission of a particular request from the host to a particular destination network address indicated by the particular request unless the particular network address is one of a set of one or more network addresses stored by the intermediate device.

23. An apparatus as recited in claim 22, wherein a network address of the server device is not among the set of one or more network addresses stored by the intermediate device.

24. An apparatus for providing leased network addresses for a host from a server executing on a server device, wherein communications between the host and the server device are filtered by an intermediate device, comprising:

a network interface that is coupled to the intermediate device for receiving a first request for a leased network address for the host from the intermediate device;

a processor; and

one or more stored sequences of instructions which, when executed by the processor, cause the processor to carry out the steps of;

generating a response for the host offering a leased network address for a particular period of time, including inserting first data comprising a network address of the intermediate device into a portion of the response designated for indicating a network address of the server for subsequent communication from the host to the server;

sending the response to the host through the intermediate device; and

wherein the intermediate device forwards the request including second data indicating the request is directed to the intermediate device and including third data indicating services related to providing leased network addresses.

25. An apparatus as recited in claim 24, further comprising means for formatting the response according to a dynamic host configuration protocol (DHCP).

26. An apparatus as recited in claim 24, wherein the portion of the response is a server identification field in a set of optional fields for the DHCP.

27. An apparatus as recited in claim 24, wherein the request is formatted according to a dynamic host configuration protocol (DHCP).

28. An apparatus as recited in claim 24, wherein the intermediate device prevents transmission of a particular request from the host to a particular destination network address indicated by the particular request unless the particular network address is one of a set of one or more network addresses stored by the intermediate device.

29. An apparatus as recited in claim 28, wherein a network address of the server device is not among the set of one or more network addresses stored by the intermediate device.