JP2004102410A - Information distribution method, distribution server, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To continuously distribute contents without conducting re-authentication or the like in a distribution server, even when a global IP address is changed in a client computer. <P>SOLUTION: A unique domain name is imparted to an LAN 200. A global IP address is imparted to a router 202 when a PC 204 or the like in the LAN 200 is connected to the Internet. A correspondence relation between the global IP address and the domain name is stored in a dynamic DNS server 150, and its content is updated dynamically. A distribution server 102 or the like requires repeatingly name solution to the server 150, as to the domain name, when distributing the content to the PC 204 or the like. The content is thereby continued to be distributed even when the global IP address of the router 202 is changed in the midway of the distribution. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an information distribution method, a distribution server, and a program suitable for use in a distribution service of moving images and the like on the Internet.
[0002]
[Prior art]
When a client computer connected to the Internet receives content distribution from a distribution server, the client computer generally knows the domain name and the like of the distribution server, but does not know the global IP address of the distribution server. Therefore, in the client computer, the domain name of the distribution server is transmitted to a predetermined DNS server, and the global IP address assigned to the domain name is returned from the DNS server. The process of acquiring an IP address based on the other party's domain name in this manner is called "name resolution."
[0003]
When name resolution is performed in the client computer, the global IP address of the target distribution server is determined. Therefore, an IP packet (for example, a distribution request packet) having the global IP address as a destination address is transmitted from the client computer to the distribution server. Will be supplied. On the other hand, in the distribution server, referring to the source address of the packet transmitted from the client computer, the global IP address of the client computer is immediately found, so that there is no need to perform name resolution. In the distribution server, for example, if predetermined conditions such as a correct user ID and password transmitted from a client computer are satisfied, content such as a moving image is distributed to the client computer.
[0004]
[Problems to be solved by the invention]
By the way, a client computer provided in a general home or a small office is usually connected to the Internet via an Internet service provider (ISP). However, a service for assigning a fixed global IP address to each subscriber in advance is more expensive than a service for assigning a dynamic global IP address, and therefore, an IP address is usually assigned dynamically. Here, it is assumed that a line on the client computer side is disconnected for some reason while a client computer to which a dynamic global IP address is assigned via the ISP is receiving content from the distribution server. In such a case, if the client computer reconnects to the Internet via the ISP, its global IP address will be different from the address that was previously connected.
[0005]
Since the newly assigned global IP address is an unknown address in the distribution server, the client computer must continue receiving the content unless the user ID and password are input again. Can not be done. This operation is complicated for the user on the client computer side. The present invention has been made in view of the above-described circumstances, and provides an information distribution method, a distribution server, and a program that can quickly and easily continue distribution of contents even when a global IP address of a client computer is changed. It is aimed at.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, the present invention is characterized by having the following configuration. The contents in parentheses are examples.
2. The information distribution method according to claim 1, wherein a client computer whose IP address can change each time it is connected, and a DNS that stores the IP address and a predetermined domain name in the client computer in association with each other. In an information distribution method that is provided in a network (Internet) connected to a server and is executed in a distribution server that distributes information to the client computer, by notifying the DNS server of the domain name, The step of receiving an IP address from the DNS server (SP244) and the step of distributing information to the client computer using the received IP address (SP248) are repeatedly executed during the distribution of information. And
Further, in the information distribution method (modification) according to the second aspect, a client computer whose IP address can change each time a connection is made, and the IP address and a predetermined domain name are transmitted to the client computer. In an information distribution method that is provided in a network (Internet) connected to a DNS server for storing information in association with the DNS server and that distributes information to the client computer, one IP received from the DNS server is provided. A determining step of determining whether or not information can be distributed to the client computer when the address is used; and determining that the information cannot be distributed in the determining step; By notifying the server of the domain name, the DNS server Repeating the step of receiving a new IP address and the step of delivering information to the client computer using the new IP address instead of the one IP address during the delivery of the information. Features.
According to a third aspect of the present invention, there is provided a distribution server which executes the information distribution method according to the first or second aspect.
According to a fourth aspect of the present invention, there is provided a program for executing the information distribution method according to any one of the first and second aspects.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
1. Next, the overall configuration of a network system according to an embodiment of the present invention will be described with reference to FIG.
In the figure, reference numerals 204, 206, and 208 denote personal computers (PCs), which are mutually connected via a local area network (LAN) 200. A router 202 is connected to the Internet 100 via a server on the side of an Internet service provider (hereinafter, referred to as an ISP server), and exchanges packets in the LAN 200 and packets on the Internet 100 with each other. Reference numerals 102, 104, and 106 denote distribution servers that distribute contents such as moving images to client computers (for example, PCs 204, 206, and 208) that have requested distribution of the contents via the Internet 100.
[0008]
When the ISP server 108 receives a connection request via the router 202, one global IP address is assigned to the router 202. In the LAN 200, the one global IP address is shared by the plurality of PCs 204, 206, and 208 by a method such as IP masquerade. Note that a domain name is predetermined for the LAN 200. Reference numeral 150 denotes a dynamic DNS server that stores a database that associates the global IP address given by the ISP server 108 with the domain name of the LAN 200, and notifies the query source of the global IP address or domain name based on an external query. I do.
[0009]
2. Operation of embodiment 2.1. Next, the operation of the present embodiment will be described. First, when an operation of receiving a distribution service is performed in any of the PCs 204, 206, and 208, a distribution service request routine shown in FIG. 2 is started in the PC. In the figure, when the process proceeds to step SP106, it is determined whether or not the distribution service start request has been completed. If “NO” is determined here, the process proceeds to step SP108, and a distribution service start request is transmitted from the PC to the target distribution server. This distribution service start request includes the own domain name as “request source information”. The details of the processing on the distribution server side for this will be described later, but a distribution service for a moving image or the like is started between the PC and the distribution server. Next, when the process proceeds to step SP110, it is determined whether or not the user of the PC desires to stop the distribution service. Here, if “NO” is determined, the process returns to step SP106.
[0010]
In the state of receiving the content distribution service, "YES" is determined in step SP106, and thereafter, steps SP106 and SP110 are repeatedly executed, and no substantial processing is performed in this routine. During that period, an application program (for example, a moving image viewer) that receives the content performs processing corresponding to the content, such as displaying a moving image. Then, when the user performs a predetermined operation for instructing stop of the distribution service, “YES” is determined in step SP110, and the process proceeds to step SP112. Here, a distribution service stop request is transmitted from the PC to the distribution server. In this distribution service stop request, the own domain name is also included as the “request source information” of the distribution stop. Although the details of the processing on the distribution server side for this will be described later, the distribution of the content is stopped, and the processing of this routine ends.
[0011]
On the other hand, the router 202 constantly determines whether or not an IP packet received from the LAN 200 should be sent to the ISP server 108. When an IP packet to be transmitted to the ISP server 108 is detected, a network connection routine shown in FIG. 3 is called. In the figure, when the process proceeds to step SP121, it is determined whether or not the router 202 is connected to the Internet 100 via the ISP server 108. If "YES" is determined here, the process ends as it is.
[0012]
On the other hand, if “NO” is determined in the step SP121, the process proceeds to a step SP122, and a negotiation is performed between the router 202 and the ISP server 108 based on a connection protocol. Next, when the process proceeds to step SP124, the ISP server 108 assigns a global IP address. This global IP address is stored in the router 202 and used for mutual conversion between the local address in the LAN 200 and the global IP address. Next, when the process proceeds to step SP126, a DNS registration routine shown in FIG. 4 is called.
[0013]
In FIG. 4, when the process proceeds to step SP142, the own DNS name, global IP address, and password are notified to the dynamic DNS server 150, and an authentication operation is performed between the server 150 and the router 202. This is to prevent a domain name or the like from being changed by another person without permission. Next, when the process proceeds to step SP144, it is detected from the response from the dynamic DNS server 150 whether the DNS registration has succeeded or failed. Note that in step SP144, the router 202 itself may try to resolve the name of the own domain name to determine whether DNS registration is possible. Next, when the process proceeds to step SP146, it is determined whether or not the DNS registration has succeeded. If “NO” is determined here, the process returns to step SP142, and the processes of steps SP142 and SP144 are repeated until the DNS registration succeeds. If the DNS registration succeeds, the process of this routine ends.
[0014]
By the way, while any of the PCs is receiving content distribution, steps SP106 and SP110 are repeatedly executed as described above, but the line between the router 202 and the ISP server 108 is disconnected for some reason during the process. May be considered. In such a case, as described above, steps SP122 to SP126 in the network connection routine (FIG. 3) are started again in the router 202, and the ISP server 108 assigns a global IP address (SP124). Here, the assigned global IP address is generally an address different from the previously assigned global IP address. Therefore, in step SP126, the database in the dynamic DNS server 150 is updated so that the new global IP address is associated with the domain name of the router 202.
[0015]
However, even if the line is disconnected during the distribution of the content, the start of the distribution service has already been requested, so that “YES” is determined in the step SP106. That is, in such a case, step SP108 (transmission of a distribution service start request) is not executed. As described above, in the present embodiment, when the line is once disconnected and then reconnected, there is no need to re-execute the authentication, and there is an advantage that the user is released from a complicated re-authentication operation.
[0016]
2.2. Operation of Dynamic DNS Server 150 In the above step SP142, the dynamic DNS server 150 is notified of its own domain name, global IP address, and password. When the server 150 receives these data, a DNS server domain name registration routine shown in FIG. 5 is started. In the figure, when the processing proceeds to step SP204, it is determined whether or not the notified domain name is a domain name already registered in the database. If this domain name is a new domain name and is not registered in the database, "NO" is determined, and the process proceeds to step SP208. Here, the domain name and the global IP address are recorded in the database corresponding to the notified password. Then, when the process proceeds to step SP210, the client computer is notified that the DNS registration has succeeded, and the process of this routine ends.
[0017]
On the other hand, if the line is interrupted and then reconnected, the client computer notifies the server 150 of the same domain name as the previous time. In such a case, “YES” is determined in step SP204, and the process proceeds to step SP206. In step SP206, it is determined whether or not the domain name is a domain name used by the user holding the transmitted password. If the line is temporarily interrupted and then reconnected, the same password as the previous password should be supplied to the server 150, so that the determination is "YES" here, and the process proceeds to step SP208. . Thus, the contents of the database in the server 150 are updated so that the newly assigned global IP address, the domain name, and the password are associated with each other. Then, in step SP210, the client computer is notified that the DNS registration has succeeded, and the processing of this routine ends.
[0018]
Further, there is a case where a DNS registration request is transmitted to the server 150 for the same domain name from another user even though an existing user is using a certain domain name. In such a case, since the passwords of the two users are different, "NO" is determined in step SP206, and the process proceeds to step SP210. Here, the client computer of the other user is notified that the DNS registration is rejected, and the processing of this routine ends.
[0019]
Further, when the name resolution request is supplied from another computer (for example, the distribution servers 102, 104, 106) after the DNS registration of the client computer is completed, the name resolution routine shown in FIG. Is activated. In the figure, when the processing proceeds to step SP224, it is determined whether or not the IP address corresponding to the domain name requested to be resolved is registered in the database. If "YES" is determined here, the process proceeds to step SP226, and the IP address is stored in a response packet supplied to the computer that has requested name resolution. Next, when the process proceeds to step SP228, the generated response packet is transmitted to the computer requesting name resolution, and the process of this routine ends.
[0020]
On the other hand, if the IP address corresponding to the domain name requested to be resolved is not registered in the database, “NO” is determined in the step SP224, and the process proceeds to a step SP228. In this case, a packet indicating that the name resolution has not been successful is transmitted to the computer requesting name resolution, and the processing of this routine ends.
[0021]
2.3. Operation of Distribution Server As described above, in step SP108, a distribution service start request is transmitted from the client computer to the distribution server. When this distribution service start request is received by the corresponding distribution servers 102, 104, and 106, the distribution server distribution service routine shown in FIG. 7 is started. In the figure, when the processing proceeds to step SP244, the domain name of the client computer that has output the distribution service start request is supplied to the dynamic DNS server 150 in order to resolve the name. As described above, in the server 150, if the name resolution is successful, the IP address is returned to the requesting distribution server, and if the name resolution is not successful, a packet indicating that is returned to the distribution server. Is done.
[0022]
Next, when the process proceeds to step SP246, it is determined based on the packet returned from the server 150 whether or not the name resolution is successful. If the name resolution is successful, “YES” is determined, and the process proceeds to step SP248. Here, content such as a moving image is distributed to the IP address obtained by name resolution. Next, when the process proceeds to step SP250, it is determined whether a distribution service stop request has been received from the client computer. If "NO" is determined here, the process returns to step SP244, and the processes in steps SP244 to SP250 are repeated unless the name resolution is successful and the distribution service stop request is not received.
[0023]
Then, when a distribution service stop request is supplied from the client computer or when the name resolution fails, the process proceeds to step SP252 via step SP246 or SP250. Here, the distribution service in the distribution server is stopped, and the processing of this routine ends. As described above, the distribution server of the present embodiment is characterized in that name resolution is repeatedly performed for the same domain name during the distribution service. Thus, even if the IP address of the client computer is changed during distribution of the content, the distribution service can be continued following the result of the change.
[0024]
In other words, from the viewpoint of the client computer, when the connection to the Internet is once disconnected and the connection is made again, even if an IP address different from the last time is given, the user logs in to the distribution servers 102, 104 and 106. It is not necessary to perform an operation for requesting the restart of the distribution service, such as an operation, and the reception of the content can be restarted immediately.
[0025]
Further, in the present embodiment, it is easy to perform operations such as starting and stopping the distribution service from a computer other than the client computer receiving the distribution service. This is because, while the global IP address of the client computer receiving the distribution service is changed every time the connection is made, the domain name is permanently fixed, so various settings are made by designating this domain name. Because you can do it.
[0026]
Further, in the present embodiment, when the user of each client computer makes a distribution contract with a content distributor, only the domain name for receiving the content need be notified to the distributor. Thus, individual user IDs and passwords can be managed only in the dynamic DNS server 150, and management of user IDs and passwords in the individual distribution servers 102, 104, and 106 can be omitted. This simplifies processes such as authentication in the distribution server, and saves resources of the distribution server.
[0027]
In other words, this means that the user can unify secret information such as a password on the user side. Further, the password and the like are information exchanged only between the client computer and the dynamic DNS server 150. By using a dynamic DNS server operated by the ISP or existing in the same ISP network, A feature of the present embodiment is that a password or the like can be prevented from leaking to the Internet 100. By preventing the password from leaking onto the Internet 100, extremely high security can be ensured without encrypting the packet including the password and the like. As described above, according to the present embodiment, it is possible to realize a content distribution system with high security and convenience by using an inexpensive dynamic IP service instead of an expensive fixed IP service.
[0028]
3. Modifications The present invention is not limited to the above-described embodiment, and various modifications are possible as follows, for example.
(1) In the above embodiment, the information distribution method of the present invention is realized by a program operating on the distribution server. However, only this program is stored in a recording medium such as a CD-ROM or a flexible disk and distributed. They can also be distributed via transmission channels.
[0029]
(2) In the distribution server distribution service routine of the above embodiment (FIG. 7), the name resolution (SP244) is executed each time the loop of steps SP244 to SP259 is repeated. However, instead of this, it is checked whether or not the content can be distributed by the IP address currently known by the distribution server, and if the content can be distributed, the content is distributed, and if the content cannot be distributed, the content is distributed. The IP address that can be distributed may be acquired again.
[0030]
As an example, it is conceivable that a confirmation request packet is transmitted from the distribution server to the client every predetermined period, and the client that has received the confirmation request sets a protocol so as to return an acknowledgment packet to the distribution server. In the distribution server, as long as the acknowledgment packet is continuously received, the content may be continuously distributed to the previous IP address. On the other hand, if the acknowledgment packet cannot be received by the distribution server, it is highly likely that the IP address of the client computer has been changed. In such a case, the domain name of the client computer is transmitted to the dynamic DNS server 150 to resolve the name. May be executed, and the distribution of the content may be continued to the new IP address obtained as a result.
[0031]
【The invention's effect】
As described above, according to the present invention, the distribution server repeatedly executes name resolution during information distribution, or repeatedly determines whether information distribution is possible to the client computer, and determines whether distribution is impossible. Since name resolution is performed when possible, even when the IP address of the client computer is changed, information distribution can be continued without performing re-authentication or the like.
[Brief description of the drawings]
FIG. 1 is a block diagram of a network system according to an embodiment of the present invention.
FIG. 2 is a flowchart of a distribution service request routine.
FIG. 3 is a flowchart of a network connection routine.
FIG. 4 is a flowchart of a DNS registration routine.
FIG. 5 is a flowchart of a DNS server domain name registration routine.
FIG. 6 is a flowchart of a name resolution routine.
FIG. 7 is a flowchart of a distribution server distribution service routine.
[Explanation of symbols]
100: Internet, 108: ISP server, 150: Dynamic DNS server, 200: LAN, 202: Router, 102, 104, 106: Distribution server, 204, 206, 208: Personal computer.

Claims (4)

A client computer provided with a client computer whose IP address can change each time it is connected, and a DNS server for storing the client computer in association with the IP address and a predetermined domain name, In an information distribution method executed in a distribution server that distributes information to a computer,
Receiving the IP address from the DNS server by notifying the DNS server of the domain name;
And distributing information to the client computer using the received IP address during the information distribution. A client computer provided with a client computer whose IP address can change each time it is connected, and a DNS server for storing the client computer in association with the IP address and a predetermined domain name, In an information distribution method executed in a distribution server that distributes information to a computer,
A judging step of judging whether or not information can be distributed to the client computer when one IP address received from the DNS server is used;
A step of receiving a new IP address from the DNS server by notifying the DNS server of the domain name when it is determined that distribution of information is impossible in the determination step;
And distributing the information to the client computer using the new IP address instead of the one IP address, during the distribution of the information. A distribution server that executes the information distribution method according to claim 1. A program for executing the information distribution method according to claim 1.

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