DEVICE AND METHOD FOR COMMUNICATING WITH ANOTHER COMMUNICATION DEVICE VIA NETWORK FORWARDING DEVICE

• US 20070110054A1
• Filed: 11/01/2006
• Published: 05/17/2007
• Est. Priority Date: 11/16/2005
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Matsuzawa, Shigeo, Kozakai, Yasuyuki
• Granted Patent: US 8,654,755 B2
• Time in Patent Office: Days
• US Class Current: 370/389
• CPC Class Codes: H04L 61/2514 between local and global IP addresses
• CPC Class Codes: H04L 61/2517 using port numbers
• CPC Class Codes: H04L 61/2564 for a higher-layer protocol, e.g. for session initiation protocol [SIP]
• CPC Class Codes: H04L 63/0428 wherein the data content is protected, e.g. by encrypting or encapsulating the payload
• CPC Class Codes: H04L 63/061 for key exchange, e.g. in peer-to-peer networks cryptographic mechanisms or cryptographic arrangements for key agreement H04L9/0838
• CPC Class Codes: H04L 63/164 at the network layer

Abstract

The communication device includes a first transmitting unit that transmits to a server a first message transmitted according to a first protocol; a receiving unit that receives a port number message including a translated port number from the server via the network forwarding device; a first protocol processing unit that generates a second message that is to be transmitted according to the first protocol; a second protocol processing unit that generates a third message in which the first protocol is concealed by appending, to the generated second message, a header according to a second protocol; a third protocol processing unit that generates a fourth message in which the first protocol is concealed by appending, to the generated third message, a header according to a third protocol; and a second transmitting unit that transmits the generated fourth message to the server via the network forwarding device.

Claims

1. A communication device comprising:

a first transmitting unit that transmits to a server a first message created according to a first protocol that a network forwarding device can translate a source port number, the network forwarding device being operable to translate each source port number contained in a protocol header of transmitted messages into a source port number capable of communicating with an external network;

a receiving unit that receives a port number message including a translated port number from the server via the network forwarding device, the translated port number being a source port number obtained after the network forwarding device performs an address translation when the first message is transmitted to the server;

a first protocol processing unit that generates a second message that is to be transmitted according to the first protocol and in which a source port number contained in a protocol header is specified as a same value as the received translated port number;

a second protocol processing unit that generates a third message in which the first protocol is concealed by appending, to the generated second message, a header according to a second protocol which cannot be translated;

a third protocol processing unit that generates a fourth message in which the first protocol is concealed by appending, to the generated third message, a header according to a third protocol that can be translated; and

a second transmitting unit that transmits the generated fourth message to the server via the network forwarding device.

2. The device according to claim 1, wherein

the first transmitting unit further transmits to the server a communication establishment message that is transmitted according to the first protocol and includes information used when a communication according to an encryption protocol is to be established, and

the receiving unit receives the port number message via the network forwarding device, the port number message having been transmitted by the server and having been arranged so that a source port number contained in a protocol header of the communication establishment message is specified as the translated port number.

3. The device according to claim 2, wherein

the first transmitting unit further transmits to the server a communication establishment message that is transmitted according to the first protocol and includes information used when a communication according to an Internet Key Exchange (IKE) protocol is to be established.

4. The device according to claim 3, wherein

the receiving unit receives, via the network forwarding device, the port number message that has been arranged and transmitted by the server so that an area into which the translated port number is stored is added to an IKE message transmitted according to the IKE protocol and the source port number contained in the protocol header of the communication establishment message is specified as the translated port number in the added area.

5. The device according to claim 3, wherein

the receiving unit receives, via the network forwarding device, the port number message that has been arranged and transmitted by the server so that the source port number contained in the protocol header of the communication establishment message is specified as the translated port number in an unused area included in an IKE message transmitted according to the IKE protocol.

8. The device according to claim 1, wherein

each of the first protocol and the third protocol is one of a UDP and a TCP.

10. The device according to claim 1, wherein

the second protocol is an Encapsulating Security Payload (ESP).

6. A communication device comprising:

a first transmitting unit that transmits a first message to an address information providing device that provides information related to an address including a source port number, via a network forwarding device, the first message being transmitted according to a first protocol that the network forwarding device can translate a source port number, and the network forwarding device being operable to translate a source IP address and a source port number into values to make it possible to communicate with an external network, for each of tuples of a protocol, a source IP address, and a source port number that are contained in a protocol header of a transmitted message;

a receiving unit that receives an address information message from the address information providing device via the network forwarding device, the address information message including a translated port number that is a source port number obtained after the network forwarding device performs an address translation when the first message is transmitted to the address information providing device;

a first protocol processing unit that generates a second message that is to be transmitted according to the first protocol and in which a source port number contained in a protocol header is specified as a same value as the received translated port number;

a second protocol processing unit that generates a third message in which the first protocol is concealed by appending, to the generated second message, a header according to a second protocol which cannot be translated;

a third protocol processing unit that generates a fourth message in which the first protocol is concealed by appending, to the generated third message, a header according to a third protocol that can be translated; and

a second transmitting unit that transmits the generated fourth message to a server via the network forwarding device.

7. The device according to claim 6, wherein

the first transmitting unit further transmits a modified first message to the address information providing device via the network forwarding device, the modified first message being obtained by changing one of a destination IP address and a destination port number that are contained in a protocol header of the first message, and

the communication device further comprising:

a translation method verifying unit that judges whether a first translated port number is same as a second translated port number and terminates a communication when having judged that the first translated port number is not the same as the second translated port number, the first translated port number being the translated port number contained in the address information message transmitted by the address information providing device in response to the first message before the one of the destination IP address and the destination port number is changed, and the second translated port number being the translated port number contained in the address information message transmitted by the address information providing device in response to the modified first message obtained by changing the one of the destination IP address and the destination port number.

9. The device according to claim 6, wherein

each of the first protocol and the third protocol is one of a UDP and a TCP.

11. The device according to claim 6, wherein

the second protocol is an Encapsulating Security Payload (ESP).

12. A communicating method comprising:

transmitting to a server a first message transmitted according to a first protocol that a network forwarding device can translate a source port number, the network forwarding device being operable to translate each source port number contained in a protocol header of transmitted messages into a source port number capable of communicating with an external network;

receiving a port number message including a translated port number from the server via the network forwarding device, the translated port number being a source port number obtained after the network forwarding device performs an address translation when the first message is transmitted to the server;

generating a second message that is to be transmitted according to the first protocol and in which a source port number contained in a protocol header is specified as a same value as the received translated port number;

generating a third message in which the first protocol is concealed by appending, to the generated second message, a header according to a second protocol which cannot be translated;

generating a fourth message in which the first protocol is concealed by appending, to the generated third message, a header according to a third protocol that can be translated; and

transmitting the generated fourth message to the server via the network forwarding device.

13. A communicating method comprising:

transmitting a first message to an address information providing device that provides information related to an address including a source port number, via a network forwarding device, the first message being transmitted according to a first protocol that the network forwarding device can translate a source port number, and the network forwarding device being operable to translate a source IP address and a source port number into values to make it possible to communicate with an external network, for each of tuples of a protocol, a source IP address, and a source port number that are contained in a protocol header of a transmitted message;

receiving an address information message from the address information providing device via the network forwarding device, the address information message including a translated port number that is a source port number obtained after the network forwarding device performs an address translation when the first message is transmitted to the address information providing device;

generating a second message that is to be transmitted according to the first protocol and in which a source port number contained in a protocol header is specified as a same value as the received translated port number;

generating a third message in which the first protocol is concealed by appending, to the generated second message, a header according to a second protocol which cannot be translated;

generating a fourth message in which the first protocol is concealed by appending, to the generated third message, a header according to a third protocol that can be translated; and

transmitting the generated fourth message to a server via the network forwarding device.