JP2004015685A - Communication terminal and method of identifying global ip address - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To identify a global IP address assigned to a private IP address space by a general purpose means in a communication terminal on a private IP address space connected via a router comprising an NAT function. <P>SOLUTION: A mail making means 33 makes an mail addressed to the communication terminal itself, which is transmitted by a transmitting means 34 to a mail server located outside the private IP address space. A received mail screening means 36 identifies the mail transmitted by the communication terminal itself from the mails received by a mail receiving means 35, and an IP address extracting means 37 analyzes header information of the mail to extract information on the global IP address assigned to the private IP address space. The mail making means 33 makes a mail addressed to a predetermined terminal that includes the extracted global IP address information, which is transmitted by the mail transmitting means 34. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a communication terminal using network communication based on TCP / IP and a global IP address specifying method according to the communication terminal.
[0002]
[Prior art]
In recent years, with the spread of the Internet, an inexpensive, high-speed, constant connection environment to the Internet, such as an ADSL (asymmetric digital subscriber line) or a cable TV, has been enhanced. Against this background, devices that are capable of network communication based on TCP / IP (transmission control protocol / internet protocol) are increasing even in homes, and the necessity of constructing a network in homes is emerging. In such a home network environment, a private IP address space (hereinafter, referred to as a private network) is configured in the home and connected to the Internet (hereinafter, referred to as a global network), which is a global IP address space. Opportunities to communicate with each other are also increasing rapidly.
[0003]
Hereinafter, communication between the private network and the global network will be described.
[0004]
FIG. 4 shows a configuration in a case where communication is performed by connecting a private network and a global network. In FIG. 4, reference numeral 10 denotes a global network such as the Internet, which is a global IP address space, and reference numeral 11 denotes a communication terminal installed on the global network 10. Reference numeral 12 denotes a private network as a private IP address space, and reference numerals 13 and 17 denote communication terminals installed on the private network 12. Reference numeral 14 denotes an Internet service provider (hereinafter abbreviated as ISP) serving as a connection point from the private network to the global network. Reference numeral 15 denotes a global IP address acquisition device that acquires a global IP address from the ISP 14. The global IP address acquisition device 15 differs depending on the connection mode with the IPS 14. For example, in the case of ADSL connection, it is an ADSL modem, and in the case of cable TV connection, it is a dedicated connection device (cable TV modem). Also, the global IP address acquisition device 15 acquires a global IP address automatically given when communication with the IPS 14 is established. There are many.
[0005]
Reference numeral 16 has a NAT (Network Address Translator) function for performing mutual conversion between the global IP address acquired by the global IP address acquisition device 15 from the ISP 14 and the private IP addresses assigned to the communication terminals 13 and 17 on the private network. It is a router. The NAT function is generally known as RFC (request for comments) 1631.
[0006]
The communication operation between the private network and the global network configured as described above will be described below.
[0007]
First, when communication is established between the global IP address obtaining device 15 and the IPS 14, the global IP address obtaining device 15 obtains one global IP address from the IPS 14. When communication is performed from the communication terminal 13 installed on the private network 12 to the communication terminal 11 installed on the Internet 10, since the communication terminal 13 is assigned a private IP address, TCP / IP issued from the communication terminal 13 is used. Is once converted in the router 16 from the private IP address to the global IP address acquired by the global IP address acquiring device 15 in the router 16 and reaches the communication terminal 11 installed in the global network 10 through the IPS 14. I do.
[0008]
On the other hand, when communication is performed from the communication terminal 11 installed on the global network 10 to the communication terminal 13 installed on the private network 12, the global IP address acquired by the global IP address acquisition device 15 is installed on the private network 12. The communication terminal 11 is informed in advance that the TCP / IP packet is the destination of the TCP / IP packet directed to the communication terminal 13, and the communication terminal 11 transmits the TCP / IP packet to the global IP address acquired by the global IP address acquisition device 15. The TCP / IP packet which has transmitted the packet and arrived at the global IP address acquiring device 15 is further changed the destination IP address by the subsequent router 16 from the global IP address of the global IP address acquiring device 15 to the private IP address of the communication terminal 13. It is converted, to reach a communication terminal 13 installed in the private network 12.
[0009]
As described above, even when a plurality of communication terminals exist in the private network 12 at home, the communication terminal 13 connects to the global network 10 and obtains network communication with the communication terminal 11 by acquiring one global IP address. Can be realized.
[0010]
[Problems to be solved by the invention]
In the above-described conventional network communication environment, the global IP address acquisition device 15 that is indispensable when communicating from the communication terminal 11 installed on the global network 10 to the communication terminal 13 installed on the private network 12 has acquired the global IP address. There is no means for universally specifying an IP address, and there is no means for universally notifying the communication terminal 11 installed in the global network 10 of the global IP address acquired by the global IP address acquisition device 15. There is a problem that communication cannot be easily started from the communication terminal 11 installed on the network 10 to the communication terminal 13 installed on the private network 12.
[0011]
The present invention solves the above-mentioned conventional problems. A communication terminal installed in a private network 12 specifies a global IP address acquired by a global IP address acquisition device 15 by a general-purpose means, and The communication terminal installed in the global network 10 is notified of the destination of the TCP / IP packet to the communication terminal (self) installed in the global network 10 by a general-purpose means, so that the communication terminal installed in the global network 10 can use the private terminal. It is an object of the present invention to provide a communication terminal capable of easily realizing communication based on TCP / IP to a communication terminal installed on a network and a global IP address specifying method according to the communication terminal.
[0012]
[Means for Solving the Problems]
In order to achieve this object, a communication terminal according to the present invention is a communication terminal installed in a private IP address space connected to a router having a network address translation function, and an Internet mail installed outside the private IP address space. Mail sending means for sending an Internet mail via a server, mail receiving means for receiving an Internet mail via an Internet mail server, and analyzing the header information of the Internet mail received by the mail receiving means to obtain IP address information. And an IP address extracting means for extracting.
[0013]
With this configuration, a communication terminal installed in the private IP address space can extract desired IP address information from Internet mail transmitted and received via an Internet mail server installed outside the private IP address space.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
According to a first aspect of the present invention, there is provided a communication terminal installed in a private IP address space connected to a router having a network address translation function, via an Internet mail server installed outside the private IP address space. Mail sending means for sending internet mail, mail receiving means for receiving internet mail via the internet mail server, and analyzing the header information of the internet mail received by the mail receiving means to extract IP address information An IP address extracting means for analyzing the header information of the received Internet mail and extracting the IP address information, whereby the IP address information of the device on the network path can be specified. .
[0015]
In a second aspect of the present invention based on the first aspect, the IP address extracting means extracts the Internet mail by extracting the IP address information included in the Received term included in the header information of the Internet mail. It is characterized by specifying the IP address of the terminal that transmitted the message, and has the effect that the IP address information of the source communication terminal of the received Internet mail can be specified by a simple method.
[0016]
In a third aspect of the present invention based on the first aspect, the mail sending means sends Internet mail addressed to the communication terminal itself, and the IP address extracting means receives the Internet mail by the mail receiving means. Extracting IP address information from the header information of the Internet mail addressed to the communication terminal itself, thereby identifying the IP address information relating to the communication terminal itself. By extracting the address information, it is possible to specify the IP address information relating to the communication terminal itself.
[0017]
Further, according to a fourth aspect of the present invention, in the third aspect, the mail sending means transmits the Internet mail including IP address information relating to the communication terminal itself extracted and specified by the IP address extracting means. The Internet mail is transmitted to a predetermined terminal installed outside the private IP address space, and the Internet mail is sent to a predetermined terminal installed outside the private IP address space (for example, a global IP address space). , The IP address information relating to the communication terminal itself in the private IP address space can be notified to a predetermined terminal outside the private IP address space.
[0018]
In a fifth aspect of the present invention based on the third aspect, the IP address extracting means includes a global IP address set in a private IP address space for the router to translate a network address into IP address information. The global IP address assigned to the private IP address space to which the communication terminal itself belongs can be specified as IP address information.
[0019]
According to a sixth aspect of the present invention, in a communication terminal installed in a private IP address space connected to a router having a network address translation function, a method for specifying a global IP address set in the private IP address space is provided. Transmitting an Internet mail addressed to the communication terminal via an Internet mail server provided outside the private IP address space; receiving the Internet mail via the Internet mail server; Analyzing the header information of the Internet mail and extracting the IP address information relating to the communication terminal itself, and specifying the global IP address set in the private IP address space to which the communication terminal belongs. It has the effect of that.
[0020]
A seventh invention of the present invention is the communication terminal according to the sixth invention, wherein the IP address information is obtained by extracting IP address information contained in the oldest Received term contained in header information of Internet mail. Specifies a global IP address set for a private IP address space in which a communication terminal belongs, and specifies a global IP address set in a private IP address space to which a communication terminal belongs by a simple method. It has the effect that it can be specified.
[0021]
In an eighth aspect of the present invention based on the seventh aspect, the step of transmitting Internet mail containing information on the specified global IP address to a predetermined terminal installed outside the private IP address space. A communication terminal on the private IP address space by transmitting the Internet mail to a predetermined terminal installed outside the private IP address space (for example, a global IP address space). This has the effect that the IP address information relating to itself can be notified to a predetermined terminal outside the private IP address space.
[0022]
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0023]
(Embodiment 1)
FIG. 1 is a diagram showing a network environment in which a communication terminal according to the first embodiment of the present invention is used, and shows a configuration in a case where communication is performed between a private network and a global network.
[0024]
In FIG. 1, reference numeral 10 denotes a global network, and 21 denotes a communication terminal installed in the global network, such as a mobile phone terminal or a personal computer. Reference numeral 20 denotes an Internet mail server (hereinafter, referred to as a mail server) for delivering Internet mail, reference numeral 12 denotes a private network, and reference numerals 17 and 22 denote communication terminals provided on the private network. The communication terminal is the communication terminal 22. Reference numeral 14 denotes an ISP serving as a connection point from the private network 12 to the global network 10. Reference numeral 15 denotes a global IP address acquisition device for acquiring a global IP address from the ISP 14, which is an ADSL modem for ADSL connection, a dedicated connection device for cable TV connection, and the like. Reference numeral 16 denotes a router having a NAT function for performing mutual conversion between the global IP address acquired by the global IP address acquisition device 15 from the ISP 14 and the private IP addresses assigned to the communication terminals 17 and 22 on the private network 12.
[0025]
FIG. 2 shows a configuration of the communication terminal 22 according to Embodiment 1 of the present invention. In the figure, reference numeral 31 denotes a control unit, which is realized by a microcomputer which can perform a process by using an IC or software specially designed. Reference numeral 32 denotes a mail address storage unit that stores its own Internet mail address and the Internet mail address of the communication terminal 21; 33, a mail creation unit that creates a predetermined Internet mail based on an instruction from the control unit 31; A mail sending means for transmitting an Internet mail created by the mail creating means 33 according to an instruction, a mail receiving means 35 receiving an Internet mail from the mail server 20 according to an instruction from the control section 31, And 37 is an IP address extracting means for extracting IP address information from the header information of the mail selected by the received mail selecting means 36.
[0026]
Each component of the communication terminal 22 described above can be realized as specially designed hardware or a program operable by a microcomputer. In the case of a program, a CPU (Central Processing Unit) constituting the microcomputer The communication terminal 22 can function as a communication terminal 22 using hardware resources such as a memory and a memory. Therefore, the communication terminal 22 according to the present embodiment may be any device as long as it has at least the above functions.
[0027]
The operation of the communication terminal according to the present embodiment configured as described above will be described with reference to FIGS. FIG. 3 is a flowchart for explaining the operation of the communication terminal according to the present embodiment. The global IP address (acquired by global IP acquisition device 15) assigned to private network 12 in which communication terminal 22 is installed is shown. The operation for notifying the communication terminal 21 of the assigned global IP address) is shown. In the following description, it is assumed that functions necessary for sending and receiving Internet mail to and from the mail server 20 are set in advance, and that the Internet mail address of the communication terminal 22 itself and the It is assumed that the Internet mail address is set in advance.
[0028]
In FIG. 3, in step 40, based on an instruction from the control unit 31, the mail creation unit 33 reads out the Internet mail address of itself (the communication terminal 22) from the mail address storage unit 32. In step 41, the mail creating means 33 creates an Internet mail addressed to itself. A specific character string is used as the title of the mail to make it easy to specify that the mail to be created is a mail created by the user. Further, the title of this e-mail may be a character string that combines the date and time information at the time of origination or creation with the title character in order to avoid the presence of a plurality of e-mails with the same title. May be a character string obtained by combining numbers and the like that change according to the rule.
[0029]
Next, in step 42, the created mail is sent by the mail sending means 34 to the mail server 20 arranged on the global network 10. After a certain period of time, in step 43, the control section 31 receives mail from the mail server 20 by the mail receiving means 35. In step 44, the received mail selecting means 36 selects the latest mail created by itself from information such as the title of the previous mail. In step 45, the IP address extracting means 37 analyzes the header information of the selected mail.
[0030]
In the IP address extracting means 37, a received term (Received term) is present in the header information of the received Internet mail, and the mail has passed from the terminal that first sent the mail to the Received term to the terminal that last received it. Since the name and IP address information of the communication device are added in chronological order, the name and IP address information of the communication device described in the oldest Received item are the information of the communication terminal that first transmitted the mail. When the mail server 20 receives the mail, the mail server 20 recognizes the mail as being transmitted from a communication device on the same IP space as the mail server 20, and describes the name of the transmission source and IP address information. Therefore, when the mail server 20 installed in the global network 10 receives the mail from the communication terminal 22, the mail server 20 sends the source IP address information described in the Received item of the mail to the private network 12 The global IP address acquired by the global IP address acquisition device 15 converted by the NAT function of the router 16 is not the private IP address assigned to the IP address 22. Therefore, the IP address extracting means 37 can acquire a global IP address for specifying the communication terminal 22 from the global network 10.
[0031]
Next, in step 46, the mail creating means 33 reads out the Internet mail address of the communication terminal 21 notifying the extracted global IP address from the mail address storage section 32, and in step 47, the mail address is extracted by the IP address extracting means 37. A mail including a global IP address as information is generated. Then, in step 48, the mail sending means 34 sends the mail to the communication terminal 21.
[0032]
The communication terminal 21 that can be installed or connected to the global network 10 can receive the Internet mail from the communication terminal 22 to know the global IP address assigned to the private network 12 where the communication terminal 22 is located. By using this global IP address, communication with the communication terminal 22 can be easily started.
[0033]
For example, when the communication terminal 22 is a recording / reproducing device having a network communication function and the communication terminal 21 is a portable terminal having a network communication function, the communication of the global IP address according to the present embodiment allows the TCP / IP to be transmitted. It is possible to control the communication terminal 22 from the communication terminal 21 using this.
[0034]
As described above, according to the first embodiment, the mail sending unit 34, the mail receiving unit 35, and the IP address extracting unit that extracts the IP address information from the header information of the mail are transmitted to the communication terminal 22 installed on the private network 12. 37, the global IP address information of the communication terminal 22 is specified from the communication between the communication terminal 22 and the mail server 20, and is notified to the communication terminal 21 installed on the global network 10, so that a general-purpose Internet mail server is provided. When the communication terminal 21 installed on the global network 10 communicates with the communication terminal 22 installed on the private network 12 only by utilizing Internet mail, the global IP address of the communication terminal 22 21 can be notified easily It is possible to start communication from the communication terminal 21 installed in the global network 10 to the communication terminal 22 installed in the private network 12.
[0035]
In the above embodiment, the timing of executing the flowchart shown in FIG. 3 is not specified, but the global IP address of the communication terminal 22 is repeatedly extracted at regular intervals, and the result of the previous extraction and the current extraction By controlling the control unit 31 to notify the communication terminal 21 only when the result is different, unnecessary notification mail from the communication terminal 22 to the communication terminal 21 is not generated. The communication terminal 21 can be notified of the IP address.
[0036]
Although not particularly mentioned in the above description, the communication terminal according to the present embodiment is also an example of realizing the global IP address specifying method according to the sixth to eighth aspects of the present invention. Therefore, the global IP address specifying method of the present invention can be realized by software, and the software may be recorded on a predetermined recording medium and distributed, may be distributed by predetermined communication means, It may be incorporated in the memory of the device in advance.
[0037]
【The invention's effect】
As described above, the present invention is a communication terminal installed in a network in a private IP address space, provided with mail sending means, mail receiving means, and means for extracting IP address information from header information of received Internet mail. Further, by communicating with a communication terminal and an Internet mail server outside the private IP address space, the private IP space is indispensable when communication from a predetermined terminal installed outside the private IP address space to the communication terminal is performed. The set global IP address can be specified by general means only, and the global IP address can be notified to a predetermined terminal installed outside the private IP address space only by general means. Located outside the private IP address space It has excellent effect that the communication from the terminal to a private IP address communication terminal installed in a space can be easily started obtained.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a network environment including a communication terminal according to a first embodiment of the present invention. FIG. 2 is a block diagram showing a configuration of the communication terminal. FIG. 3 is a flowchart showing an operation of the communication terminal. 4 is a diagram showing the configuration of a conventional communication terminal in a network environment.
DESCRIPTION OF SYMBOLS 10 Global network 12 Private network 14 Internet service provider 15 Global IP address acquisition device 16 Router 17 Communication terminal 20 installed in private network Mail server 21 Communication terminal 22 installed in global network 22 Communication installed in global network according to the present invention Terminal 31 Control unit 32 Mail address storage unit 33 Mail creation unit 34 Mail transmission unit 35 Mail reception unit 36 Received mail selection unit 37 IP address extraction unit

Claims (8)

A communication terminal installed in a private IP address space connected to a router having a network address translation function,
Mail sending means for sending Internet mail through an Internet mail server installed outside the private IP address space;
Mail receiving means for receiving Internet mail via the Internet mail server;
A communication terminal comprising: an IP address extracting unit that analyzes header information of Internet mail received by the mail receiving unit and extracts IP address information. 2. The apparatus according to claim 1, wherein the IP address extracting unit specifies an IP address of a terminal that has transmitted the Internet mail by extracting IP address information included in a Received term included in header information of the Internet mail. Communication terminal. The mail sending means sends Internet mail addressed to the communication terminal itself, and the IP address extracting means extracts IP address information from header information of the Internet mail addressed to the communication terminal received by the mail receiving means. 2. The communication terminal according to claim 1, wherein the communication terminal specifies IP address information relating to the communication terminal itself. The mail transmitting means transmits Internet mail including IP address information relating to the communication terminal itself extracted and specified by the IP address extracting means to a predetermined terminal installed outside the private IP address space. The communication terminal according to claim 3, wherein: 4. The communication terminal according to claim 3, wherein said IP address extracting means extracts, as IP address information, a global IP address set in a private IP address space for the router to translate a network address. In a communication terminal installed in a private IP address space connected to a router having a network address translation function, a method for specifying a global IP address set for the private IP address space,
Transmitting Internet mail addressed to the communication terminal via an Internet mail server installed outside the private IP address space;
Receiving the Internet mail via the Internet mail server;
Analyzing the header information of the received Internet mail and extracting the IP address information relating to the communication terminal itself. The IP address information specifies a global IP address set for a private IP address space where a communication terminal is installed by extracting IP address information included in a Received term included in header information of Internet mail. 7. The global IP address specifying method according to claim 6, wherein: 8. The global IP address specifying method according to claim 7, further comprising a step of transmitting an Internet mail including the information of the specified global IP address to a predetermined terminal installed outside the private IP address space.

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