Methods and systems for establishing communications through firewalls and network address translators

• US 20030112823A1
• Filed: 12/17/2001
• Published: 06/19/2003
• Est. Priority Date: 12/17/2001
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Liu, Xin, Chu, Lon-Chan, Iverson, Kristofer Noel, Collins, Leonard Alan, Xu, Yikang
• Granted Patent: US 7,227,864 B2
• Time in Patent Office: Days
• US Class Current: 370/474
• CPC Class Codes: H04L 2101/663 Transport layer addresses, e.g. aspects of transmission control protocol [TCP] or user datagram protocol [UDP] ports
• CPC Class Codes: H04L 61/00 Network arrangements, protocols or services for addressing or naming
• CPC Class Codes: H04L 61/2567 for reachability, e.g. inquiring the address of a correspondent behind a NAT server
• CPC Class Codes: H04L 61/2578 without involvement of the NAT server
• CPC Class Codes: H04L 63/029 Firewall traversal, e.g. tunnelling or, creating pinholes
• CPC Class Codes: H04L 67/104 Peer-to-peer [P2P] networks
• CPC Class Codes: H04L 67/14 Session management for real-time applications in data packet communications networks H04L65/1066
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]

Abstract

Disclosed are methods that enable communications to be established regardless of the presence of communications blockers, e.g., firewalls and NATs, in the path between two computing devices. Two devices each establish communications with a rendezvous service. Through the service, the devices signal each other to set up direct, peer-to-peer communications between themselves. If the devices fail to establish direct communications, then they invoke a relay service that provides the illusion of direct communications. In another aspect, an originating device attempts to establish communications with a recipient, using an address and port number associated with the recipient. If that attempts fails, possibly because a firewall is blocking communications, then the originating device retries using a port normally held open by firewalls. If this attempt also fails, then the originating device invokes the services of a proxy to negotiate a port acceptable for use by the recipient and by any intervening firewalls.

Claims

1. A method for a first computing device to establish communications with a second computing device, the method comprising:

sending a first communications request addressed to a rendezvous service, the first communications request specifying the second computing device; and

waiting to receive communications from the second computing device.

2. The method of claim 1 wherein specifying the second computing device comprises specifying an element in the set:

a name of the second computing device, a public address of the second computing device, a public address of a Network Address Translator (NAT) behind which sits the second computing device.

3. The method of claim 1 further comprising:

establishing communications with the rendezvous service.

4. The method of claim 1 further comprising:

waiting for a first failure indication, indicating that the second computing device failed to establish communications with the first computing device; and

if the first failure indication occurs before communications from the second computing device are received, then sending communications addressed to the second computing device.

5. The method of claim 4 wherein the first failure indication is in the set:

an event associated with a timer associated with sending the first communications request addressed to the rendezvous service, reception of communications from the rendezvous service.

6. The method of claim 4 further comprising:

waiting for a second failure indication, indicating that the communications addressed to the second computing device failed to establish communications with the second computing device; and

if the second failure indication occurs before communications from the second computing device are received, then establishing communications with a relay service and sending a second communications request addressed to the rendezvous service, the second communications request specifying the relay service.

7. The method of claim 6 wherein the second failure indication is an event associated with a timer associated with sending the communications addressed to the second computing device.

8. The method of claim 6 wherein sending a second communications request addressed to the rendezvous service comprises sending an indication that the first computing device failed to establish communications with the second communications device.

9. The method of claim 6 wherein specifying the relay service comprises specifying an element in the set:

a name of the relay service, a public address of the relay service.

10. The method of claim 6 wherein the second communications request further specifies an identifier of a session on the relay service.

11. A computer-readable medium having instructions for performing the method of claim 1.

12. A method for a second computing device to establish communications with a first computing device, the method comprising:

receiving a first communications request from a rendezvous service, the first communications request specifying the first computing device;

sending communications addressed to the first computing device; and

waiting to receive communications from the first computing device.

13. The method of claim 12 wherein specifying the first computing device comprises specifying an element in the set:

a name of the first computing device, a public address of the first computing device, a public address of a Network Address Translator (NAT) behind which sits the first computing device.

14. The method of claim 12 further comprising:

establishing communications with the rendezvous service.

15. The method of claim 12 further comprising:

waiting for a first failure indication, indicating that the second computing device failed to establish communications with the first computing device; and

if the first failure indication occurs before communications from the first computing device are received, then sending communications addressed to the rendezvous service.

16. The method of claim 15 wherein the first failure indication is an event associated with a timer associated with sending the communications addressed to the first computing device.

17. The method of claim 15 wherein sending communications addressed to the rendezvous service comprises sending an indication that the second computing device failed to establish communications with the first computing device.

18. The method of claim 12 further comprising:

receiving a second communications request from the rendezvous service, the second communications request specifying a relay service; and

establishing communications with the relay service.

19. The method of claim 18 wherein specifying the relay service comprises specifying an element in the set:

a name of the relay service, a public address of the relay service.

20. The method of claim 18 wherein the second communications request further specifies an identifier of a session on the relay service.

21. A computer-readable medium having instructions for performing the method of claim 12.

22. A method for a first computing device to establish communications with a second computing device, the method comprising:

sending first communications addressed to the second computing device, using an address and a first port number associated with the second computing device;

waiting to receive communications from the second computing device;

waiting for a first failure indication, indicating that the first communications failed to establish communications with the second computing device; and

if the first failure indication occurs before communications from the second computing device are received, then sending second communications addressed to the second computing device, using the address associated with the second computing device and a second port number.

23. The method of claim 22 wherein the first failure indication is an event associated with a timer associated with sending the first communications addressed to the second computing device.

24. The method of claim 22 wherein the second port number is a port number associated with sending encrypted communications to a firewall.

25. The method of claim 24 wherein the second port number is 443.

26. The method of claim 22 further comprising:

waiting for a second failure indication, indicating that the second communications failed to establish communications with the second computing device; and

if the second failure indication occurs before communications from the second computing device are received, then sending a first communications request to a proxy, requesting a proxy connection to the second computing device using the address and first port number associated with the second computing device.

27. The method of claim 26 wherein the second failure indication is an event associated with a timer associated with sending the second communications addressed to the second computing device.

28. The method of claim 26 further comprising:

waiting for a third failure indication, indicating that the first communications request to the proxy failed to establish communications with the second computing device; and

if the third failure indication occurs before communications from the second computing device are received, then sending a second communications request to the proxy, requesting a proxy connection to the second computing device using the address associated with the second computing device and a second port number.

29. The method of claim 28 wherein the third failure indication is in the set:

an event associated with a timer associated with sending the first communications request to the proxy;

reception of communications from the proxy.

30. The method of claim 28 wherein the second port number is a port number associated with sending encrypted communications to a firewall.

31. The method of claim 30 wherein the second port number is 443.

32. A computer-readable medium having instructions for performing the method of claim 22.

33. A method for a first computing device to establish communications with a second computing device, the method comprising:

sending first communications addressed to the second computing device, using an address and a first port number associated with the second computing device;

waiting to receive communications from the second computing device;

waiting for a first failure indication, indicating that the first communications failed to establish communications with the second computing device; and

if the first failure indication occurs before communications from the second computing device are received, then sending a first communications request to a proxy, requesting a proxy connection to the second computing device using the address and first port number associated with the second computing device.

34. The method of claim 33 wherein the first failure indication is an event associated with a timer associated with sending the first communications addressed to the second computing device.

35. The method of claim 33 further comprising:

waiting for a second failure indication, indicating that the first communications request to the proxy failed to establish communications with the second computing device; and

if the second failure indication occurs before communications from the second computing device are received, then sending second communications addressed to the second computing device, using the address associated with the second computing device and a second port number.

36. The method of claim 35 wherein the second failure indication is in the set:

an event associated with a timer associated with sending the first communications request to the proxy;

reception of communications from the proxy.

37. The method of claim 35 wherein the second port number is a port number associated with sending encrypted communications to a firewall.

38. The method of claim 37 wherein the second port number is 443.

39. The method of claim 35 further comprising:

waiting for a third failure indication, indicating that the second communications failed to establish communications with the second computing device; and

if the third failure indication occurs before communications from the second computing device are received, then sending a second communications request to the proxy, requesting a proxy connection to the second computing device using the address associated with the second computing device and a second port number.

40. The method of claim 39 wherein the third failure indication is an event associated with a timer associated with sending the second communications addressed to the second computing device.

41. The method of claim 39 wherein the second port number is a port number associated with sending encrypted communications to a firewall.

42. The method of claim 41 wherein the second port number is 443.

43. A computer-readable medium having instructions for performing the method of claim 33.