Method and apparatus to modify network identifiers at data servers

• US 20060184647A1
• Filed: 02/16/2005
• Published: 08/17/2006
• Est. Priority Date: 02/16/2005
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Dalal, Mitesh, Somasundaram, Mahadev, Dixit, Vineet Ramesh, Khare, Amol
• Granted Patent: US 7,930,365 B2
• Time in Patent Office: Days
• US Class Current: 709/219
• CPC Class Codes: H04L 63/0272 Virtual private networks
• CPC Class Codes: H04L 63/0281 Proxies
• CPC Class Codes: H04L 63/168 above the transport layer
• CPC Class Codes: H04L 67/02 based on web technology, e.g. hypertext transfer protocol [HTTP]

Abstract

A method of modifying network identifiers at data servers is disclosed. A virtual private network (VPN) gateway server generates a Hypertext Transfer Protocol (HTTP) request. The HTTP request not only requests data from a data server that is within a VPN, but also instructs the data server to modify (“mangle”) URLs that are contained within the requested data so that the URLs refer to the VPN gateway server. The VPN gateway server sends the HTTP request toward the data server. As a result, the data server modifies the URLs so that the VPN gateway server does not need to. When such a modified URLs is selected in a web browser, the web browser generates an HTTP request that is directed to the VPN gateway server'"'"'s URL, which, unlike the unmodified URLs, can be resolved by domain name servers that are outside of the VPN.

Claims

1. A method comprising:

receiving an original HTTP request that requests data from a data server;

generating a new Hypertext Transfer Protocol (HTTP) request that (a) requests the data from the data server and (b) instructs the data server to modify one or more Uniform Resource Locators (URLs) that are contained within the data so that the one or more URLs refer to a gateway server; and

sending the new HTTP request toward the data server.

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

receiving an HTTP response that contains the data, wherein the HTTP response originated from the data server;

determining whether the HTTP response indicates that the data server modified the one or more URLs;

if the HTTP response does not indicate that the data server modified the one or more URLs, then modifying the one or more URLs so that the one or more URLs refer to the gateway server; and

sending the HTTP response toward a client that requested the data.

3. A method as recited in claim 2, further comprising the step of:

if the HTTP response indicates that the data server modified the one or more URLs, then, before sending the HTTP response toward the client, removing, from the HTTP response, an HTTP response header that indicates that the data server modified the one or more URLs.

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

receiving a second HTTP request that indicates a URL of the gateway as a consequence of a particular URL having been modified by the data server, wherein the particular URL contains a URL that is associated with a particular data server;

generating a third HTTP request that is based on the second HTTP request; and

sending the third HTTP request toward the particular data server.

5. A method a'"'"'s recited in claim 1, wherein the step of generating a new HTTP request comprises the step of:

generating an HTTP request header that indicates a URL of the gateway server.

6. A method of offloading Uniform Resource Locator (URL) mangling, the method comprising the steps of:

receiving a first Hypertext Transfer Protocol (HTTP) request that indicates a first URL of a file that is stored by a first HTTP server, wherein the file contains a second URL that cannot be resolved by domain name servers that are outside of a virtual private network (VPN) that contains the first HTTP server;

generating a second HTTP request that requests the file from the first HTTP server, wherein the second HTTP request contains a first directive that (a) indicates that the first HTTP server should modify URLs in the file, and (b) indicates a URL of a gateway for the VPN;

sending the second HTTP request toward the first HTTP server;

receiving an HTTP response that contains the file, in which the second URL has been modified so that the URL of the gateway precedes information that was previously contained in the second URL;

determining that the HTTP response contains a second directive that indicates that URLs in the file have been modified;

in response to determining that the HTTP response contains the second directive, removing the second directive from the HTTP response; and

after removing the second directive from the HTTP response, sending the HTTP response toward a client from which the first HTTP request originated.

7. A method comprising:

receiving a Hypertext Transfer Protocol (HTTP) request that requests specified data;

determining whether the HTTP request contains an instruction to modify one or more Uniform Resource Locators (URLs) that are contained within the specified data so that the one or more URLs refer to a specified gateway server;

in response to determining that the HTTP request contains an instruction to modify the one or more URLs, modifying the one or more URLs so that the one or more URLs refer to the specified gateway server; and

sending, toward the specified gateway server, an HTTP response that contains the specified data, in which the one or more URLs have been modified to refer to the specified gateway server.

8. A computer-readable medium carrying one or more sequences of instructions which, when executed by one or more processors, cause the one or more processors to carry out the steps of:

receiving an original HTTP request that requests data from a data server;

generating a new Hypertext Transfer Protocol (HTTP) request that (a) requests the data from the data server and (b) instructs the data server to modify one or more Uniform Resource Locators (URLs) that are contained within the data so that the one or more URLs refer to a gateway server; and

sending the new HTTP request toward the data server.

9. A computer-readable medium as recited in claim 8, further comprising instructions which, when executed by the one or more processors, cause the one or more processors to carry out the steps of:

receiving an HTTP response that contains the data, wherein the HTTP response originated from the data server;

determining whether the HTTP response indicates that the data server modified the one or more URLs;

if the HTTP response does not indicate that the data server modified the one or more URLs, then modifying the one or more URLs so that the one or more URLs refer to the gateway server; and

sending the HTTP response toward a client that requested the data.

10. A computer-readable medium as recited in claim 9, further comprising instructions which, when executed by the one or more processors, cause the one or more processors to carry out the step of:

if the HTTP response indicates that the data server modified the one or more URLs, then, before sending the HTTP response toward the client, removing, from the HTTP response, an HTTP response header that indicates that the data server modified the one or more URLs.

11. A computer-readable medium as recited in claim 8, further comprising instructions which, when executed by the one or more processors, cause the one or more processors to carry out the steps of:

receiving a second HTTP request that indicates a URL of the gateway as a consequence of a particular URL having been modified by the data server, wherein the particular URL contains a URL that is associated with a particular data server;

generating a third HTTP request that is based on the second HTTP request; and

sending the third HTTP request toward the particular data server.

12. A computer-readable medium as recited in claim 9, further comprising instructions which, when executed by the one or more processors, cause the one or more processors to carry out the step of:

generating an HTTP request header that indicates a URL of the gateway server.

13. An apparatus comprising:

means for receiving an original HTTP request that requests data from a data server;

means for generating a new Hypertext Transfer Protocol (HTTP) request that (a) requests the data from the data server and (b) instructs the data server to modify one or more Uniform Resource Locators (URLs) that are contained within the data so that the one or more URLs refer to a gateway server; and

means for sending the new HTTP request toward the data server.

14. An apparatus comprising:

a network interface that is coupled to a data network for receiving one or more packet flows therefrom;

a processor;

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

receiving an original HTTP request that requests data from a data server;

generating a new Hypertext Transfer Protocol (HTTP) request that (a) requests the data from the data server and (b) instructs the data server to modify one or more Uniform Resource Locators (URLs) that are contained within the data so that the one or more URLs refer to a gateway server; and

sending the new HTTP request toward the data server.