JP3834770B2 - Name resolution method and apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a name resolution method and apparatus, and more particularly, to a name resolution method and apparatus via a resolver when an IP (Internet Protocol) network user is simultaneously connected to a plurality of IP networks.
[0002]
[Prior art]
In today's Internet name resolution, a resolver that performs recursive queries on the Internet user side requests name resolution from the local DNS server, the local DNS server looks for the answer, and returns the answer to the resolver that has requested name resolution. Is. At that time, the resolver that performs the recursive query is connected to only one IP network.
[0003]
In recent years, it has been considered to construct an IP network independent of the Internet (hereinafter referred to as an independent network) prepared with unique content, and simultaneously provide the Internet and the independent network to Internet users. Further, a form in which an Internet user contracts with a plurality of ISPs, that is, a form in which a plurality of ISPs are simultaneously connected is also considered.
[0004]
For example, in Japanese Patent Laid-Open No. 2001-175561, in a system connected to a plurality of networks, an inquiry destination can be efficiently selected, and the speed until obtaining an inquiry result is improved. A domain name system is disclosed.
[0005]
In this technique, using the name given from the domain name search means as a key, the query destination server information stored in the search destination information storage unit is searched by the data processing means, and the IP address acquired corresponding to the name is stored in the domain Send to name search means. If the inquiry server information is not stored in the search destination information storage unit, the IP address of the inquiry server associated with the name is read from the standard search destination information storage unit and transmitted to the domain name search unit. .
[0006]
In other words, in this technique, by specifying an inquiry destination for each search request name, an inquiry to a server that does not have information on the search request is not performed, and the efficiency of the domain name search is improved.
However, this technique has a problem that it is necessary to store a key name in the search destination information storage unit.
[0007]
[Problems to be solved by the invention]
That is, in the above prior art, although it is made not to make an inquiry to a server that does not have information for a search request, when publishing content on a network, it is necessary to attach a domain name including a key name, Free domain names cannot be assigned (domain name assignment is limited).
Furthermore, when adding a name that becomes a new key, it is necessary to change the search destination information storage unit of all users connected to the network, and countermeasures are also required.
[0008]
The present invention has been made in view of such circumstances, and the object of the present invention is to solve the above-mentioned problems in the prior art and to enable name resolution even when a plurality of IP networks are connected simultaneously. Is to provide a simple name resolution method and apparatus.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, a name resolution method according to the present invention is a name resolution method for IP network users who are simultaneously connected to a plurality of IP networks, the step of storing priorities of the plurality of IP networks to be connected; , One resolver that makes a recursive inquiry broadcasts a recursive inquiry to the local DNS servers of the plurality of IP networks to be connected, and receives a response from the local DNS server and stores it for a certain period of time. And a step of selecting one answer from the stored answers and notifying the application of the selected answer.
[0010]
In the name resolution method according to the present invention, in the step of selecting one answer from the stored answers, the priority of the answers is given by associating the stored answers with the priority of the IP network. It is characterized in that one answer having a name resolution is selected from the answers having a high priority among the answers given priority.
[0011]
Further, in the name resolution method according to the present invention, in addition to the above steps, when the application requesting name resolution cannot obtain the content with the selected answer, the resolver resolves the name of the answer. It is characterized in that it has a step of selecting one answer having the next highest priority from the answers that have been made and notifying the application.
[0012]
On the other hand, the name resolution device according to the present invention is a name resolution device for resolving names of IP network users who are simultaneously connected to a plurality of IP networks, and means for storing priorities of the plurality of IP networks to be connected A resolver that makes a recursive inquiry broadcasts a recursive inquiry to a local DNS server of the plurality of IP networks to be connected, and receives a response from the local DNS server and stores it for a certain period of time. And a means for selecting one answer from the stored answers, and a means for notifying the application of the selected answer.
[0013]
In the name resolution device according to the present invention, the means for selecting one answer from the stored answers attaches the priority order of the answers by associating the stored answers with the priority order of the IP network. One of the answers having a name resolution is selected from the answers having a high priority among the answers given priority. [0014]
Further, in the name resolution device according to the present invention, when the application requesting name resolution fails to obtain content with the selected answer, the resolver is able to resolve the name from the answers. It has a function of selecting one answer with high priority and notifying the application.
[0015]
The name resolution method according to the present invention can be executed by program control of a computer, and the scope of rights of the present invention extends to such a program as well as a recording medium recording this program. Needless to say.
[0016]
[Action]
According to the present invention, as described above, the resolver makes a recursive inquiry to the local DNS servers of the plurality of IP networks to be connected by broadcast, and selects one of the obtained answers. As a result, name resolution can be performed even when a plurality of IP networks are connected simultaneously.
[0017]
Further, in the present invention, in the step of selecting one answer from the stored answers, the priority order of the answers is given by associating the stored answers with the network priority, and the priority order is given. From the answers, one answer whose name can be resolved can be selected from those having a high priority.
[0018]
In addition, when the application requesting name resolution fails to obtain the content with the selected answer, the resolver selects one answer with the next highest priority in the name resolution from the answers. To notify the application.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail based on preferred examples shown in the drawings.
[0020]
FIG. 6 is an example of an IP network connection related to conventional general name resolution. The Internet user 00 is connected to one network (in this case, the Internet 20). One resolver 10 that makes a recursive query issues a name resolution request to the local DNS server 21.
[0021]
On the other hand, FIG. 1 shows an example of a plurality of IP network connections related to name resolution targeted in the present invention. Network user 01 is simultaneously connected to a plurality of IP networks. The resolver 30 is connected to a function 61 for storing the priority order of the connected IP network.
[0022]
Here, the IP networks to be simultaneously connected are the Internet 20, the independent network 40, and the independent network 50. A plurality of IP networks can be simultaneously connected to the Internet 20. The connection network is not limited to this form. Here, the resolver 30 includes a local DNS server 21 (IP address 128.10.10.2), a local DNS server 22 (IP address 200.10.10.2), a local DNS server 41 (IP address 192.168.10.2), and a local DNS server 51 (IP address). 192.10.20.2), the feature is that a name resolution request is issued by broadcast.
[0023]
FIG. 2 is a block diagram illustrating a functional configuration of the resolver 30 that performs a recursive inquiry.
The resolver 30 is associated with a means 61 for storing the priorities of the plurality of IP networks to be connected, and an application 71 that requests the resolver 30 for name resolution and receives a name response from the resolver 30.
[0024]
Specifically, the resolver 30 includes a means 31 for receiving a name resolution request from the application 71, a means 32 for performing a recursive inquiry to a local DNS server of the connected multiple IP network, and the local DNS. A means 33 for receiving an answer from the server and storing it for a predetermined time, a means 34 for selecting one answer from the stored answers, and a means 35 for notifying the application of the selected answer. This block diagram is an example, and the function may be embedded in another place.
[0025]
FIG. 3 is an explanatory diagram illustrating an example of a procedure from selection of an answer from an association between an answer IP address from the local DNS server and a network priority.
[0026]
The table 61 ′ of the means 61 for storing the priority order of the plurality of IP networks stores the correspondence relation between the network priority order and the local DNS server of the corresponding network. A table 33 ′ of the means 33 for receiving a response from the local DNS server and storing it for a certain period of time stores the correspondence between the response IP address received from the local DNS server and the local DNS server that returned the response.
[0027]
In addition, the table 34 ′ of the means 34 for selecting one answer from the stored answers includes a network priority order stored in the table 61 ′ from the answers stored in the table 33 ′. Information for selecting one answer based on the is stored.
[0028]
The priority order of the reply IP addresses is set by using the IP address of the local DNS server as a trigger. Among the IP addresses that can be replied, they are candidates for passing to the application in descending order of priority of the replied IP addresses.
In the example of FIG. 3, the IP address 192.168.20.10 received from the local DNS server with the IP address 192.168.20.2 is a candidate to be passed to the application (see the table 34 ′ of the means 34 for selecting one answer from the stored answers). ).
[0029]
FIG. 4 is a block diagram illustrating a functional configuration related to cooperation between a resolver and an application.
Here, in addition to the functions shown in FIG. 2, an application 72 for confirming the success / failure of the content GET and a means 73 for notifying the application 71 of the number of rejections only when the content GET is failure are provided. 30 'includes means 36 for determining whether re-request is necessary, and means 37 for determining the end of name resolution. The configuration shown in this block diagram is also an example, and the function may be embedded in another location.
[0030]
FIG. 5 is a flowchart illustrating an example of an operation procedure for name resolution.
Hereinafter, an example of performing name resolution of www.akairo.com will be described with reference to FIGS.
[0031]
The resolver 30 (30 ′) is simultaneously connected to the Internet 20 from two points, and to the independent network 40 and the independent network 50 simultaneously. The local DNS server that the resolver 30 (30 ′) goes to inquire about the name is the local DNS server 21 (128.10.10.2), the local DNS server 22 (200.10.10.2), the local DNS server 41 (192.168.10.2), and the local DNS server. 51 (192.168.20.2).
[0032]
Here, the means 61 for storing the priorities of a plurality of IP networks to be connected includes the independent network 40 to which the local DNS server 41 with the IP address 192.168.102 is inquired as the priority 1 and the local with the IP address 192.168.20.2. The independent network 50 to which the DNS server 51 is inquired is the priority 2, the Internet 20 to which the local DNS server 21 with the IP address 128.1010.2 is inquired is the priority 3, and the local DNS server 22 with the IP address 200.10.10.2 is inquired. It is assumed that the previous Internet 20 is stored as priority 4.
[0033]
When the user who requests the content requests http://www.akairo.com to the Web browser, the Web application 71 requests the resolver 30 (30 ′) for name resolution (step 101). Resolver 30 (30 ') that has received the request for name resolution determines that it is the first name resolution request (step 102), and broadcasts http://www.akairo.com to the four local DNS servers. A recursive name resolution request is issued (step 103).
[0034]
Each local DNS server performs iterative name resolution and returns an IP address to resolver 30 (30 '). Specifically, the resolver 30 (30 ′) is “Not found” from the local DNS server 41 of the independent network 40, “192.168.20.10” from the local DNS server 51 of the independent network 50, and local of the independent network 20 “210.200.10.10” is received from the DNS servers 21 and 22 respectively (step 104).
[0035]
The resolver 30 (30 ′) also calls the priority storage table 61 ′ in parallel with steps 103 and 104 (step 109). Then, priority is given to the answers received in step 104 by using the IP address of the local DNS server as a trigger (step 105). In this case, “Not found” is priority order 1, “192.168.20.10” is priority order 2, and “210.200.10.10” is priority orders 3 and 4.
[0036]
Among them, since the name resolution of “Not found” with priority 1 is not completed, the resolver 30 (30 ′) selects “192.168.20.10” with priority 2 and requested the web application 71 for name resolution. (Steps 106 and 107). The Web application 71 makes a content request to the terminal whose IP address is “192.168.20.10” (step 108).
[0037]
Information indicating that the resolver 30 (30 ′) could not obtain the content from the Web application 71 when there was some failure in the terminal having the IP address “192.168.20.10” or the network that reciprocates, and the content could not be obtained. Is recognized (steps 106 to 108), and it is recognized that it is a re-request (steps 101 and 102).
[0038]
The resolver 30 (30 ′) selects the next priority “210.200.10.10” IP address and notifies the Web application 71 of the IP address (steps 106 and 107). The cooperation between the resolver 30 (30 ′) and the Web application 71 ends when the Web application 71 obtains content or notifies the resolver 30 (30 ′) that there is no reply IP address (step 110).
[0039]
According to the above embodiment, in the name resolution of IP network users who are simultaneously connected to a plurality of IP networks, an inquiry is made to all the connected networks, and among the received answers, the answers with high priority that can be resolved are automatically The effect that it becomes possible to select automatically is acquired.
[0040]
The name resolution method according to the present invention can be executed by program control of a computer, and the scope of rights of the present invention extends to such a program as well as a recording medium recording this program. Needless to say.
[0041]
The above embodiment shows an example of the present invention, and the present invention should not be limited to this, and appropriate modifications and improvements may be made without departing from the gist of the present invention. Needless to say.
[0042]
For example, although omitted in FIGS. 2 and 4, the means 32 for making a recursive query to the local DNS server by broadcast does not read the IP address of the target DNS each time, but in the broadcast means. These IP addresses may be held. Thereby, processing is simplified and speeded up.
[0043]
Further, by providing connection ports corresponding to the number of local DNS servers at the broadcast destination on the outlet side of the broadcast means, the communication path provided between each local DNS server is used to its full capacity. It is possible to improve the substantial communication capability.
[0044]
【The invention's effect】
As described above in detail, according to the present invention, it is possible to realize a name resolution method and apparatus capable of performing name resolution even when a plurality of IP networks are simultaneously connected.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an example of a plurality of network connections related to name resolution targeted in the present invention. FIG. 2 is a block diagram illustrating a functional configuration related to a resolver 30 that performs a recursive inquiry.
FIG. 3 is a diagram illustrating an example of a procedure from selection of an answer from an association between an answer IP address from a local DNS server and a network priority order;
FIG. 4 is a block diagram illustrating a functional configuration related to cooperation between a resolver and an application.
FIG. 5 is a flowchart showing an example of an operation procedure at the time of name resolution.
FIG. 6 is a diagram showing an example of a network connection related to conventional name resolution.
[Explanation of symbols]
00, 01 Network user 20 Internet 21, 22, 41, 51 Local DNS server 30 Resolver 31 Means for receiving name resolution request from application 32 Means for performing recursive inquiry to local DNS servers of multiple IP networks to be connected 33 means for receiving an answer from the local DNS server and storing it for a certain period of time 34 means for selecting one answer from the stored answers 35 means for notifying the selected answer to the application 36 determining whether re-request is required for the resolver 30 ′ Means 37 Means 40, 50 for determining the end of name resolution Independent network 61 Means 71 for storing priorities of a plurality of IP networks to be connected 71 Application for requesting name resolution to resolver and receiving name answer 72 Content GE Application means for confirming success / failure of T 73 Means for notifying the number of times of failure when the content cannot be obtained

Claims (6)

A method for resolving names of IP network users simultaneously connected to a plurality of IP networks having a local DNS server that answers different IP addresses with the same domain name ,
Storing priorities of the plurality of IP networks to be connected;
One resolver that performs recursive queries
Recursively querying each local DNS server of the plurality of IP networks to be connected;
Receiving a response from each of the local DNS servers and storing it for a certain period of time;
Selecting one answer from the stored answers;
Notifying the application of this selected answer;
When the application requesting name resolution fails to obtain the content with the selected answer, selecting the next highest priority answer that has been resolved for the answer and notifying the application A name resolution method characterized by comprising:   In the step of selecting one answer from the stored answers, the answers are prioritized by associating the stored answers with the priority of the IP network, and name resolution is performed from the prioritized answers. The name resolution method according to claim 1, wherein one answer having a higher priority is selected. A name resolution apparatus for resolving names of IP network users simultaneously connected to a plurality of IP networks having a local DNS server that answers different IP addresses with the same domain name ,
Means for storing priorities of the plurality of IP networks to be connected;
A resolver that performs recursive queries,
The resolver is
Means for performing a recursive query by broadcast to each local DNS server of the plurality of IP networks to be connected;
Means for receiving a response from each local DNS server and storing it for a certain period of time;
A means of selecting one answer from the stored answers;
Means to notify the application of this selected answer;
Means for selecting one answer with the next highest priority that has been resolved for the name of the answer and notifying the application when the application requesting name resolution fails to obtain the content with the selected answer. A name resolution device characterized by that.   The means for selecting one answer from the stored answers prioritizes the answers by associating the stored answers with the IP network priority, and selects a name from the prioritized answers. 4. The name resolution apparatus according to claim 3, wherein one answer that can be resolved is selected from those having a high priority.   The program for making a computer perform each step in the name resolution method of any one of Claim 1 or Claim 2.   A computer-readable recording medium on which the program according to claim 5 is recorded.

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