Reducing network configuration complexity with transparent virtual private networks

• US 20040268121A1
• Filed: 06/30/2003
• Published: 12/30/2004
• Est. Priority Date: 06/30/2003
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Huitema, Christian, Shelest, Art
• Granted Patent: US 7,305,705 B2
• Time in Patent Office: Days
• US Class Current: 713/156
• CPC Class Codes: H04L 2209/56 Financial cryptography, e.g. electronic payment or e-cash
• CPC Class Codes: H04L 2209/76 Proxy, i.e. using intermediary entity to perform cryptographic operations network architectures or network communication protocols using hop-by-hop encryption H04L63/0464
• CPC Class Codes: H04L 2209/80 Wireless network architectures or network communication protocols for wireless network security H04W12/00
• CPC Class Codes: H04L 63/0272 Virtual private networks
• CPC Class Codes: H04L 63/029 Firewall traversal, e.g. tunnelling or, creating pinholes
• CPC Class Codes: H04L 63/0442 wherein the sending and receiving network entities apply asymmetric encryption, i.e. different keys for encryption and decryption cryptographic mechanisms or cryptographic arrangements for public-key encryption H04L9/30
• CPC Class Codes: H04L 63/08 for authentication of entities cryptographic mechanisms or cryptographic arrangements for entity authentication H04L9/32
• CPC Class Codes: H04L 63/083 using passwords cryptographic mechanisms or cryptographic arrangements for entity authentication using a predetermined code H04L9/3226
• CPC Class Codes: H04L 63/0853 using an additional device, e.g. smartcard, SIM or a different communication terminal cryptographic mechanisms or cryptographic arrangements for entity authentication involving additional secure or trusted devices H04L9/3234
• CPC Class Codes: H04L 63/1458 Denial of Service
• CPC Class Codes: H04L 63/166 at the transport layer
• CPC Class Codes: H04L 9/3218 using proof of knowledge, e.g. Fiat-Shamir, GQ, Schnorr, ornon-interactive zero-knowledge proofs

Abstract

A firewall acts as a transparent gateway to a server within a private network by initiating an unsolicited challenge to a client to provide authentication credentials. After receiving the client'"'"'s credentials, the firewall verifies the authentication credentials and establishes a secure channel for accessing the server. Data destined for the server from the client may be forwarded through the firewall using the secure channel. The firewall may sign, or otherwise indicate that data forwarded to the server is from a client that the firewall has authenticated. The firewall also may provide some level of authentication to the client. While connected to the server, the client may access other servers external to the private network without having the data associated with the other servers pass through the private network. The firewall reduces configuration information that a client otherwise must maintain to access various private network servers.

Claims

1. In a private network comprising a resource and a firewall, which acts as a gateway by controlling client desired access to the private network resource, a method of establishing a connection to the private network resource while balancing authentication processing requirements between a client and the firewall to mutually guard against denial of service attacks, the method comprising the acts of:

receiving, by the firewall, a request from the client to access the private network resource, wherein the request from the client is made to the private network resource without any knowledge of the firewall;

requesting, by the firewall, the client to provide one or more client credentials to authenticate the client;

sending, by the firewall, one or more firewall credentials to authenticate the firewall, wherein generating the one or more firewall credentials consumes some level of limited firewall processing resources;

receiving one or more client credentials at the firewall, wherein generating the one or more client credentials consumes some level of limited client processing resources similar in magnitude with the consumption of the limited firewall processing resources;

verifying, by the firewall, the one or more client credentials;

establishing a secure channel for accessing the private network resource in response to the verification of the one or more client credentials; and

forwarding data from the client destined to the private network resource through the firewall using the secure channel.

2. The method of claim 1, wherein the step of verifying comprising the act of:

continuing an exchange of credentials between the client and the firewall to incrementally increase a level of trust between the client and the firewall until a predefined threshold of trust is reached.

3. The method of claim 1, wherein the private network resource is one of a host, gateway or server.

4. The method of claim 1, wherein the only data passed through the firewall from the client are those packets of data destined to the private network resource.

5. The method of claim 1, further comprising the act of:

establishing a connection with a resource of a separate private network while simultaneously maintaining the secure channel of the private network.

6. The method of claim 1, further comprising the act of:

establishing a connection with another private network resource while simultaneously maintaining the secure channel of the private network.

7. The method of claim 1, wherein the act of forwarding the data from the client to the private network resource is accomplished through the use of an authenticated channel, the method further comprising the act of:

signing, by the firewall, the packets of data from the client destined to the private network resource, wherein the singing indicates that the client has passed one or more security check implemented in the firewall.

8. The method of claim 7, further comprising the act of:

discarding unsigned packets of data received by the protected private network resource.

9. The method of claim 1, wherein the one or more client credential received is selected from at least one of a user'"'"'s name, client'"'"'s IP address, password, passport, smart-card or credit card number.

10. The method of claim 1, wherein the request, by the firewall, for the client to provide one or more client credentials is a question, and wherein the one or more client credentials received is an answer to the question.

11. The method of claim 1, wherein the client is a second firewall.

12. In a private network comprising a resource and a firewall, which acts as a gateway by controlling client desired access to the private network resource, a method of establishing a connection to the private network resource while balancing authentication processing requirements between a client and the firewall to mutually guard against denial of service attacks, the method comprising steps for:

initiating a series of authentication transactions designed to impose commensurable processing burdens on the client requesting access to the private network resource and the firewall operating as a gateway for the private network, wherein the client initially is unaware that the firewall operates as a gateway for the private network, and wherein each authentication transaction incrementally increases a level of trust between the client and the firewall until the authentication of the client and the firewall are sufficiently verified;

for each of the series of authentication transactions;

authenticating to the client in accordance with one of the series of authentication transactions; and

challenging the client to authenticate in a manner requiring similar processing burdens; and

granting the client access to the private network resource through the firewall upon completing the series of authentication transactions.

13. The method of claim 12, wherein the step for challenging the client to authenticate comprises the acts of:

requesting, by the firewall, the client to provide one or more client credentials;

receiving one or more client credentials at the firewall; and

verifying, by the firewall, the one or more client credentials.

14. The method of claim 13, wherein the one or more credentials authenticated is at least one of a user'"'"'s name, client'"'"'s IP address, password, passport, smart-card or credit card number.

15. The method of claim 13, wherein the request, by the firewall, for the client to provide one or more client credentials is a question, and wherein the one or more client credentials received is an answer to the question.

16. The method of claim 12, wherein once the client is granted access to the private network resource the only data passed through the firewall from the client are those packets of data destined to the private network resource.

17. The method of claim 12, wherein the step for granting includes the act of:

establishing an authenticated channel between the firewall and the private network resource, wherein the authenticated channel is established through signing the data from the firewall.

18. The method of claim 17, further comprising the act of:

discarding any unsigned packets of data received by the private network resource.

19. The method of claim 12, wherein the private network resource is one of a host, gateway or server.

20. The method of claim 12, wherein the client is a second firewall.

21. The method of claim 12, further comprising the act of:

establishing a connection with another resource of a separate private network while simultaneously maintaining a secured channel between the firewall and the client.

22. The method of claim 12, further comprising the act of:

establishing a connection with another private network resource while simultaneously maintaining a secured channel between the firewall and the client.

23. In a private network comprising a resource and a firewall, which acts as a gateway by controlling client desired access to the private network resource, a computer readable media carrying computer executable instructions that implement a method of establishing a connection to the private network resource while balancing authentication processing requirements between a client and the firewall to mutually guard against denial of service attacks, the method comprising the acts of:

receiving, by the firewall, a request from the client to access the private network resource, wherein the request from the client is made to the private network resource without any knowledge of the firewall;

requesting, by the firewall, the client to provide one or more client credentials to authenticate the client;

sending, by the firewall, one or more firewall credentials to authenticate the firewall, wherein generating the one or more firewall credentials consumes some level of limited firewall processing resources;

receiving one or more client credentials at the firewall, wherein generating the one or more client credentials consumes some level of limited client processing resources similar in magnitude with the consumption of the limited firewall processing resources;

verifying, by the firewall, the one or more client credentials;

establishing a secure channel for accessing the private network resource in response to the verification of the one or more client credentials; and

forwarding data from the client destined to the private network resource through the firewall using the secure channel.

24. The method of claim 23, wherein the step of verifying comprising the act of:

continuing an exchange of credentials between the client and the firewall to incrementally increase a level of trust between the client and the firewall until a predefined threshold of trust is reached.

25. The method of claim 23, wherein the private network resource is one of a host, gateway or server.

26. The method of claim 23, wherein the only data passed through the firewall from the client are those packets of data destined to the private network resource.

27. The method of claim 23, further comprising the act of:

establishing a connection with a resource of a separate private network while simultaneously maintaining the secure channel of the private network.

28. The method of claim 23, further comprising the act of:

establishing a connection with another private network resource while simultaneously maintaining the secure channel of the private network.

29. The method of claim 23, wherein the act of forwarding the data from the client to the private network resource is accomplished through the use of an authenticated channel, the method further comprising the act of:

signing, by the firewall, the packets of data from the client destined to the private network resource, wherein the singing indicates that the client has passed one or more security check implemented in the firewall.

30. The method of claim 29, further comprising the act of:

discarding unsigned packets of data received by the protected private network resource.

31. The method of claim 23, wherein the one or more client credential received is selected from at least one of a user'"'"'s name, client'"'"'s IP address, password, passport, smart-card or credit card number.

32. The method of claim 23, wherein the request, by the firewall, for the client to provide one or more client credentials is a question, and wherein the one or more client credentials received is an answer to the question.

33. The method of claim 23, wherein the client is a second firewall.

34. In a private network comprising a resource and a firewall, which acts as a gateway by controlling client desired access to the private network resource, a computer readable media carrying computer executable instructions that implement a method of establishing a connection to the private network resource while balancing authentication processing requirements between a client and the firewall to mutually guard against denial of service attacks, the method comprising steps for:

initiating a series of authentication transactions designed to impose commensurable processing burdens on the client requesting access to the private network resource and the firewall operating as a gateway for the private network, wherein the client initially is unaware that the firewall operates as a gateway for the private network, and wherein each authentication transaction incrementally increases a level of trust between the client and the firewall until the authentication of the client and the firewall are sufficiently verified;

for each of the series of authentication transactions;

authenticating to the client in accordance with one of the series of authentication transactions; and

challenging the client to authenticate in a manner requiring similar processing burdens; and

granting the client access to the private network resource through the firewall upon completing the series of authentication transactions.

35. The method of claim 34, wherein the step for challenging the client to authenticate comprises the acts of:

requesting, by the firewall, the client to provide one or more client credentials;

receiving one or more client credentials at the firewall; and

verifying, by the firewall, the one or more client credentials.

36. The method of claim 35, wherein the one or more credentials authenticated is at least one of a user'"'"'s name, client'"'"'s EP address, password, passport, smart-card or credit card number.

37. The method of claim 35, wherein the request, by the firewall, for the client to provide one or more client credentials is a question, and wherein the one or more client credentials received is an answer to the question.

38. The method of claim 35, wherein once the client is granted access to the private network resource the only data passed through the firewall from the client are those packets of data destined to the private network resource.

39. The method of claim 34, wherein the step for granting includes the act of:

establishing an authenticated channel between the firewall and the private network resource, wherein the authenticated channel is established through signing the data from the firewall.

40. The method of claim 39, further comprising the act of:

discarding any unsigned packets of data received by the private network resource.

41. The method of claim 34, wherein the private network resource is one of a host, gateway or server.

42. The method of claim 34, wherein the client is a second firewall.

43. The method of claim 34, further comprising the act of:

establishing a connection with another resource of a separate private network while simultaneously maintaining a secured channel between the firewall and the client.

44. The method of claim 34, further comprising the act of:

establishing a connection with another private network resource while simultaneously maintaining a secured channel between the firewall and the client.

45. In a private network comprising a server and a firewall, which acts as a gateway by controlling access to the server, a method of providing access to the server through the firewall without a client knowing about the firewall, the method comprising the acts of:

receiving at the firewall, an access request from the client that is directed to the server because the client does not know that the firewall operates as a gateway for the server;

generating one or more authentication credentials at the firewall that demonstrate a level of trust between the server and the firewall;

the firewall sending a request for the client to authenticate to the firewall, the request including the one or more firewall authentication credentials so that the client knows of the level of trust between the server and the firewall without having to make a separate request;

receiving at the firewall, one or more authentication credentials from the client;

the firewall verifying the one or more client authentication credentials; and

thereafter, allowing the client to access the server through the firewall.

46. A method as recited in claim 45, further comprising the acts of:

establishing a secure connection between the firewall and the server; and

forwarding data received from the client to the server over the secure connection.

47. A method as recited in claim 45, further comprising an acts of:

receiving at the firewall data from the client;

the firewall signing the received data; and

the firewall forwarding the signed data to the server.

48. A method as recited in claim 45, wherein the server comprises a host or a gateway.

49. A method as recited in claim 45, wherein the client comprises another firewall.

50. A method as recited in claim 45, wherein the client maintains a separate connection with another server, and wherein only data intended for the private network passes through the firewall.

51. A method as recited in claim 50, wherein the other server is part of a separate and distinct virtual private network.