TWI738253B - Client connection method of domain name ststem - Google Patents

Abstract

A client connection method of Domain Name Systeem (DNS) connecting to servers is adapted to a client end and a server end of a Domain Name System, wherein a communication module of the client end communicably connects to one or more name servers of the server end. The method comprises: obtaining a number of one or more name servers of the server end by a processing module of the client end; selectively activating a parallel mode according to the number by the processing module; controling the communication module to perform a health monitoring procedure according to the number by the processing module; setting a mark on the name server that fails the health monitoring procedure by the processing module when at least one name server fails the health monitoring procedure, and updating the number according to the name server that fails the health monitoring procedure and controlling the communication module to performs a service procedure on unmarked name servers of the server end by the processing module.

Description

Client connection method of domain name system service

The invention relates to a domain name system, in particular to a method for a client of the domain name system to connect to a server.

Domain Name System (DNS) is an essential service on the Internet, and most companies have the need and need to set up a DNS server. Among them, BIND (Berkeley Internet Name Domain) is the commonly used DNS on the market. Service program. Since enterprises or financial institutions have high-frequency usage of DNS services, it is really necessary for DNS service programs to adapt and automatically adjust. Existing DNS service programs such as BIND cannot dynamically adjust the parameter settings on its own, so it often takes too long for the DNS server to respond to the DNS client, which in turn causes the client to query the DNS for a long response time and cause DNS service The program's resources are exhausted. Even if the existing DNS service has a time-out setting mechanism, it still cannot improve the above-mentioned problems. In addition, the existing DNS service programs such as BIND do not have any monitoring function, so the current status of the DNS server cannot be notified to the system administrator of the DNS client in real time, resulting in a decrease in overall service performance.

In view of this, there is indeed a need for an improved DNS service program and its control method in order to improve the above-mentioned shortcomings.

In view of this, the present invention proposes a client connection method of the domain name system service, which can dynamically adjust the setting parameters in the domain name system service, and add a monitoring mechanism to the existing domain name system service program, so that it can Reduce system performance that is degraded by waiting for response from the server. In addition, the client connection method of the domain name system service proposed by the present invention can dynamically mark whether each name server responds in real time, so the overall performance of the client when executing the domain name system service can be improved.

According to an embodiment of the present invention, a client connection method of a domain name system service is suitable for the client and server sides of the domain name system, wherein the client has a processing module and a communication module, and the communication module The communication is connected to the server side, and the server side has one or more name servers. The client connection method of the domain name system service includes: the processing module obtains one or more name servers on the server side The number of servers; the processing module selectively enables the parallel mode according to the number of servers; the processing module controls the communication module to perform health check procedures according to the number of servers; among them, when at least one of one or more name servers fails to pass health During the check procedure, the processing module sets a flag for at least one name server that has failed the health check procedure; and the processing module updates the number of servers based on the name server that has failed the health check procedure, and controls the communication module to the server side One or more name servers are running service procedures that are not set in the flags.

The above description of the disclosure and the following description of the embodiments are used to demonstrate and explain the spirit and principle of the present invention, and to provide a further explanation of the scope of the patent application of the present invention.

The detailed features and advantages of the present invention will be described in detail in the following embodiments. The content is sufficient to enable anyone familiar with the relevant art to understand the technical content of the present invention and implement it accordingly, and according to the content disclosed in this specification, the scope of patent application and the drawings. Anyone who is familiar with relevant skills can easily understand the purpose and advantages of the present invention. The following examples further illustrate the viewpoints of the present invention in detail, but do not limit the scope of the present invention by any viewpoint.

The AIX/Linux system often used in financial institutions or enterprises can be connected to the Domain Name Server (DNS) server through the BIND (Berkeley Internet Name Domain) software running on the client computer, thereby realizing DNS clients The service function of the end and the server end.

Please refer to Figure 1. FIG. 1 is a diagram of a system structure applicable to a client connection method of a domain name system service according to an embodiment of the present invention.

The client connection method of the domain name system service described in an embodiment of the present invention is applicable to the client 10 and the server 30 of the domain name system 100, wherein the client 10 has a processing module 12 and a communication module 14 . The communication module 14 is communicatively connected to the server terminal 30, and the server terminal 30 has a plurality of name servers, such as the server 32, the server 34, and the server 36 shown in FIG. 1 as an example. The present invention does not limit the number of name servers that can be connected

The client 10 is, for example, a computer running an AIX system or a Linux operating system. The present invention does not limit the type of hardware of the client 10. In one embodiment, the processing module 12 of the client 10 can run BIND (Berkeley Internet Name Domain) software and connect to the server 30 through the communication module 14.

Please refer to FIG. 2, which illustrates a flowchart of a client connection method of a domain name system service according to an embodiment of the present invention. In general, in this embodiment, a preset script file can be loaded through the Shell interface under the operating system of the client 10 to implement the steps described below.

Please refer to step S1, the processing module 12 obtains the number of one of the name servers (such as the server 32, the server 34, and the server 36) of the server end 30. In this step S1, the client 10 determines the number of servers currently available for connection. Taking the example shown in FIG. 1, the number of said servers is three. Specifically, the processing module 12 can read the configuration file resolv.conf under the etc directory, and find the number of nameserver keywords in the file through the Shell command written in the script file, thereby obtaining the number of servers.

Please refer to step S3, the processing module 12 selectively activates a parallel mode according to the number of servers. The aforementioned parallel mode means that the client 10 can simultaneously connect to multiple name servers 32, 34, and 36 on the server side when performing the following steps. In one embodiment, the parallel mode represents that the processing module 12 allows the communication module 14 to simultaneously send multiple packets to one or more name servers 32, 34, and 36 in the server 30. If the processing module 12 chooses not to enable the parallel mode, the processing module 12 enables the single transmission mode. The single mode means that the client 10 only sends packets to a single name server (when the number of servers obtained in step S1 is less than or equal to 1 o'clock).

Specifically, through the Shell command written in the script file, set the option rotate parameter. Setting option rotate means that processing module 12 can use all name servers in resolv.conf, not just the first one. In other words, after enabling the option rotate function, the load of the first name server originally located in resolv.conf can be reduced, and each instance of the processing module 12 can use the name servers listed in resolv.conf in turn.

Please refer to FIG. 3, which shows a detailed flowchart of step S3. After step S1 in FIG. 2 is completed, step S31 is continued.

Please refer to step S31 to determine whether the number of servers is less than or equal to one. If the judgment result is "Yes", step S32 and step S33 are executed. If the judgment result is "No", step S34 and step S35 are executed. It should be noted that the present invention does not need to limit the execution sequence of step S32 and step S33. Similarly, the execution sequence of step S34 and step S35 does not need to be limited.

When the number of servers is less than or equal to 1, please refer to step S32, the processing module 12 prohibits the communication module 14 from sending a packet to each of the one or more name servers 32, 34, and 36 in the server 30 . Specifically, the processing module 12 removes the parameter setting option rotate.

Please refer to step S33, the processing module reduces the waiting time of the communication module 14 and the number of retransmissions of the communication module 14. Specifically, the processing module reduces the setting value of RES_TIMEOUT representing the waiting time in the etc/environment configuration file, and reduces the setting value of RES_RETRY representing the number of retransmissions. In practice, if there is only one name server in resolv.conf and its response time is too long, reducing the waiting time and retransmission times through step S33 can prevent the business service program operated by the client 10 from being exhausted due to long waiting The problem of resources.

When the number of servers is greater than 1, please refer to step S34. The processing module 12 allows the communication module 14 to send a packet to each of the one or more name servers 32, 34, and 36 in the server 30. . Specifically, the processing module 12 adds the option rotate parameter setting.

Please refer to step S35, the processing module 12 restores the default value of the waiting time of the communication module 14 and the default value of the number of retransmissions of the communication module 14. In detail, when the number of name servers available for query is sufficient, the default values of the two parameters RES_TIMEOUT and RES_RETRY can be restored adaptively. However, the present invention is not limited to the above examples.

After step S32 and step S33 in FIG. 3 are completed, or after step S34 and step S35 are completed, step S5 in FIG. 2 will continue to be executed.

Please refer to step S5, the processing module 12 controls the communication module 14 to execute a health check procedure according to the number of servers. Please also refer to FIG. 4, which shows a detailed flowchart of step S5.

Please refer to step S51, the processing module 12 selects one or more of the name servers 32, 34, and 36 in the server end 30. In one embodiment, the order of selecting the name servers 32, 34, and 36 may follow the order in which the nameserver keywords appear in the resolv.conf configuration file, but the invention is not limited to this. For example, when this step S51 is executed for the first time, the processing module 12 selects the server 32.

Please refer to step S53, the processing module 12 controls the communication module 14 to send packets to the selected name server (such as the server 32) and accumulate the waiting time. Following the previous example, when the communication module 14 starts to send packets to the server 32, the processing module 12 starts a timer to start accumulating the waiting time.

After step S53 is executed, if the client terminal 10 does not receive a response from the selected name server (such as the server 32), step S55 is executed. Conversely, if the client 10 receives a response from the selected name server (such as the server 32), step S57 is executed.

Please refer to step S55. When the communication module 14 does not receive the response packet sent by the selected name server (such as server 32) and the waiting time reaches the threshold, the processing module 12 instructs the server 32 to perform a health check procedure It is "Failed".

Please refer to step S57. When the communication module 14 receives the response packet sent by the selected name server (such as the server 32) and the waiting time has not reached the threshold, the processing module 12 designates the health check procedure as "pass".

In summary, the process shown in FIG. 4 can adopt a parallel execution strategy, and the number of threads is equal to the number of servers. In this way, the client 10 realizes the health status check of all the name servers 32, 34, and 36 of the server 30, and can save the overall operation time when the number of servers is large. In another embodiment, the client can adopt a serial execution strategy to sequentially perform health checks on each name server.

Please refer to step S7 to determine whether any name servers have failed the health check procedure. In other words, after step S5 is executed multiple times in parallel, or after step S5 is executed multiple times in succession, the processing module 12 determines whether at least one of the one or more name servers 32, 34, and 36 has failed the health check procedure. . If the judgment result is "Yes", the processing module 12 sets a mark (Mark Down) for the name server that has not passed the health check procedure. In one embodiment, the marking processing module 12 generates a log file. This log file is used to record the identification number of the name server that failed the health check procedure. Assuming that the name server that failed the health check procedure is server 36, the identification number can be the virtual number of server 36, or the Internet protocol address of server 36, or the MAC address of server 36. The present invention There is no restriction on the form of the data recorded in the mark. In another implementation, the processing module 12 further controls the communication module 14 to send the log file to a monitoring device. In this way, the external monitoring equipment can instantly know which name servers are currently unavailable (such as server 36).

Please refer to step S8. The processing module 12 updates the number of servers based on the name servers (such as server 36) that have failed the health check procedure. For example, because the server 36 has not passed the health check procedure, the processing module 12 updates the server value obtained in step S1 from 3 to 2. On the other hand, if the processing module 12 determines that the number of servers in the name server that have not passed the health check procedure is equal to the number of servers obtained in step S1, in other words, when the number of available name servers is 0, it is also That is, when all current name servers are abnormal, the processing module 12 generates a warning signal and controls the communication module 14 to send the warning signal. In one embodiment, the warning signal is a push or short message sent to the mobile phone of the system administrator. In another embodiment, the warning signal is an email sent to a system librarian.

Please refer to step S9, the processing module 12 controls the communication module 14 to execute the DNS service procedure on the name servers (such as the server 32 and the server 34) that are not marked in the server end 30. On the other hand, for a name server (such as server 36) that has been set with a flag, the processing module 36 prohibits the query command sent during the execution of the DNS service program from being sent to this server 36

In one embodiment, steps S5 to S9 will be periodically repeated. For example, in step S9, after executing the DNS service procedure on the name servers (such as server 32 and server 34) that have not been marked with a set flag, and after a specified time has elapsed, it will return to step S5, and the processing module 12 will depend on the number of servers The control communication module 14 performs a health check procedure on each of the name servers 32, 34, and 36 of the server end 30. The above-mentioned checking procedure still includes the name server 36 that will be previously set and labeled. If the name server 36 for which the mark is set passes the health check procedure, the processing module 12 cancels its mark. When the subsequent execution reaches step S9, the processing module 12 controls the communication module 14 to cancel the mark of the server 30 The name server 36 executes the service program.

In summary, the client connection method of the domain name system service proposed in the above embodiment of the present invention implements the following two main functions based on the script file loaded into the client operating system to improve and optimize the DNS client End query performance. The first main effect of the present invention is to dynamically adjust multiple parameters in the BIND software, thereby achieving the effect of DNS query optimization. In detail, the present invention dynamically adjusts multiple parameters in the BIND software by allowing the DNS client to query the name server for the current status. The parameters that are dynamically adjusted include options rotate, RES_RETRY, and RES_TIMEOUT parameters. When the DNS client business service needs to initiate a large number of queries to the name server, if it is executed according to the default values of RES_RETRY and RES_TIMEOUT, the problem of too long response time may easily occur. Especially when there is only one name server available, the above situation is more likely to occur. Therefore, the present invention dynamically adjusts the setting values of options rotate, RES_RETRY, and RES_TIMEOUT, which can alleviate the problem of too long response time, and ensure that the DNS client business service program will not cause the business service program to consume too long response time due to the query DNS. Exhaust resources.

The second main effect of the present invention is to realize a name server where Mark Down is unavailable, and to provide a mechanism for instant notification and monitoring by the client. The present invention can confirm whether each current name server has a response through a regular health check procedure. If a certain name server does not exist or fails, the original DNS client program will not know that the name server does not exist, which will cause invalid queries to be sent and affect the overall query performance. The client connection method of the domain name system service of the present invention implements a marking mechanism so that the packet inquired by the client is no longer sent to an unavailable name server. In addition, the client connection method of the domain name system service of the present invention can generate a log file for the monitoring device as a warning condition. At the same time, the client connection method of the domain name system service of the present invention can send an e-mail to immediately notify the system administrator of the client to proceed. Another advantage of the present invention is that it can periodically detect whether the previously marked name server has been restored. If it is determined that the name server is ready for use, the present invention will automatically restore the service that the DNS client asks the name server.

On the whole, the client connection method of the domain name system service proposed by the present invention can dynamically adjust the setting parameters in the domain name system service and add a monitoring mechanism to the existing domain name system service program. Therefore, It can reduce the system performance that is reduced by waiting for a response from the server. In addition, the client connection method of the domain name system service proposed by the present invention can dynamically mark whether each name server responds in real time, so the overall performance of the client when executing the domain name service can be improved.

Although the present invention is disclosed in the foregoing embodiments, it is not intended to limit the present invention. All changes and modifications made without departing from the spirit and scope of the present invention fall within the scope of the patent protection of the present invention. For the scope of protection defined by the present invention, please refer to the attached scope of patent application.

S1~S9: steps S31~S35: steps S51~S57: steps 100: Domain name system 10: client 12: Processing module 14: Communication module 30: server side 32, 34, 36: name server

FIG. 1 is a diagram of a system structure applicable to a client connection method of a domain name system service according to an embodiment of the present invention. FIG. 2 shows a flowchart of a client connection method of a domain name system service according to an embodiment of the present invention. FIG. 3 is a detailed flowchart of step S3 in FIG. 2. FIG. 4 is a detailed flowchart of step S5 in FIG. 2.

S1~S9: steps

Claims (7)

A client connection method of a domain name system service is applicable to a client and a server side of the domain name system, wherein the client has a processing module and a communication module, and the communication module is connected in communication The server side, and the server side has one or more name servers, the client connection method of the domain name system service includes: obtaining the one or more name servers of the server side by the processing module Name server, the number of servers; use the processing module to selectively enable a parallel mode based on the number of servers, where when the number of servers is less than or equal to 1, use the processing module to prohibit the communication module from simultaneously Each of the one or more name servers on the server side sends a packet; and uses the processing module to reduce the waiting time of one of the communication modules and the number of retransmissions of one of the communication modules; and when the server When the number of servers is greater than 1, the processing module allows the communication module to simultaneously send a packet to each of the one or more name servers on the server side; and uses the processing module to the communication module The waiting time of the group is restored to a preset value and the number of retransmissions of the communication module is restored to another preset value; after the processing module selectively activates the parallel mode according to the number of servers, The processing module is used to control the communication module to execute a health check procedure according to the number of servers; wherein when at least one of the one or more name servers fails the health check procedure, the processing module is used to The at least one name server that fails the health check procedure sets a flag; and the processing module updates the number of servers based on the name server that fails the health check procedure, and controls the communication module to the server The one or more name servers for which the flag is not set on the server side execute a service procedure. The client connection method of the domain name system service according to claim 1, wherein the parallel mode includes: using the processing module to allow the communication module to simultaneously send a plurality of packets to the one or Multiple name servers. The client connection method of the domain name system service according to claim 1, wherein using the processing module to control the communication module to execute a health check procedure according to the number of servers includes: selecting the server in the server One of one or more name servers; and using the processing module to control the communication module to send a packet to the selected name server, and accumulate a waiting time; wherein when the communication module does not receive the The selected name server sends a response packet and the waiting time reaches a threshold, the processing module indicates that the health check procedure is not passed; and when the communication module receives the selected name server sent The response packet and the waiting time have not yet reached the threshold; the processing module specifies that the health check procedure is passed. The client connection method of the domain name system service according to claim 1, wherein when the at least one of the one or more name servers fails the health check procedure, and fails the health check procedure When the number corresponding to the at least one name server is equal to the number of the server, the processing module generates a warning signal and sends the warning signal through the communication module. The client connection method of the domain name system service according to claim 4, wherein the warning signal is a push broadcast or an email. The client connection method of the domain name system service according to claim 1, wherein after the service procedure is executed on the server, the method further includes: controlling the communication module to execute by the processing module according to the number of servers The health check procedure; wherein when the at least one name server for which the mark is set passes the health check procedure; the processing module cancels the mark; and the processing module controls the communication module to the server side The at least one name server whose mark has been cancelled executes the service procedure. The client connection method of the domain name system service according to claim 1, wherein setting the mark with the processing module to the at least one name server that has failed the health check procedure includes: generating with the processing module A log file for recording an identification number of the at least one name server that fails the health check procedure; and the processing module controls the communication module to send the log file to a monitoring device.

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