WO2021142867A1 - Dns server selection method and proxy server - Google Patents

Abstract

Disclosed is a DNS server selection method. The method comprises: obtaining a target data access request, and resolving the target data access request to obtain a carried target domain name (S101); determining a target DNS server in a default DNS server and at least one alternative DNS server according to a target historical resolution record corresponding to the target domain name, such that the target DNS server resolves the target domain name (S102); and receiving a resolution result fed back by the target DNS server, sending the target data access request to a target source station to which the resolution result points, and updating the target historical resolution record on the basis of a response result of the target source station (S103).

Description

A DNS server selection method and proxy server

cross reference

This application refers to the Chinese patent application No. 202010052800.3 filed on January 7, 2020, entitled "A DNS server selection method and proxy server", which is fully incorporated into this application by reference.

Technical field

This application relates to the field of Internet technology, and in particular to a method for selecting a DNS server and a proxy server.

Background technique

With the rapid development of the Internet and the increasingly complex network environment, the traditional centralized deployment of resource nodes can no longer meet the needs of users. To ensure that users in different regions can get a good experience when visiting websites, many content providers will use distributed The deployment method is to deploy resource nodes in different regions, which also leads to the existence of multiple origin sites for the same domain name. Before the user sends an access request for data resources, when the destination IP address cannot be obtained from the local host table, the locally configured DNS server must first perform domain name resolution to obtain the server IP corresponding to the access domain name. Generally speaking, the user A default DNS server and an alternate DNS server are usually configured locally, and the default DNS server is used first, and a DNS request is sent to the default DNS server to obtain the destination address information (port number and IP address), and then based on the The destination address information constructs an access request and sends it to the server pointed to by the destination address.

However, the existing preferential use of the default DNS server to respond to the user's domain name resolution request has the following characteristics: When a certain DNS server is selected as the default DNS server, the system will only be able to respond to the destination address information normally when the DNS server cannot normally feed back the destination address information. Select an alternate DNS server for domain name resolution; when the DNS server successfully resolves a domain name, no matter whether the resolved origin site can respond normally or not, the user's access request for the domain name will always be directed to the origin site. .

In view of this, it is necessary to provide a new DNS server selection method and proxy server to solve the above shortcomings.

Summary of the invention

The purpose of some embodiments of this application is to provide a DNS server selection method and proxy server, which can automatically select a suitable DNS server for a domain name.

In order to achieve the above-mentioned purpose, on the one hand, this application provides a method for selecting a DNS server. The method is applied to a proxy server. The proxy server is configured with a default DNS server and at least one candidate DNS server, and stores historical resolution records. The method includes: obtaining a target data access request, and parsed from the target data access request to obtain the carried target domain name; according to the target historical resolution record corresponding to the target domain name, the default DNS server and the at least one Determine the target DNS server among the candidate DNS servers, so that the target DNS server can resolve the target domain name; receive the resolution result fed back by the target DNS server, and send the target data access request to the resolution The target source station pointed to by the result, and based on the response result of the target source station, the target historical analysis record is updated.

In order to achieve the foregoing objective, another aspect of the present application also provides a proxy server. The proxy server includes a memory and a processor. The memory is used to store a computer program. When the computer program is executed by the processor, the The above DNS server selection method.

It can be seen that, in the technical solution provided by this application, the proxy server obtains the user's access request and resolves to obtain the target domain name, and selects the DNS server based on the historical resolution record, and performs secondary resolution on the target domain name, thereby ensuring the DNS server The origin server pointed to by the destination address information of the response can respond normally.

Specifically, the default DNS server and at least one alternative DNS server can be preset in the proxy server, and the historical resolution records of each domain name can be stored. When the access request sent by the user is received, the historical resolution records can be stored first The target historical resolution record corresponding to the target domain name is queried, and then according to the value recorded in the target historical resolution record, the target DNS server is determined from the default DNS server and at least one candidate DNS server, and the target DNS server determines the target domain name. Perform domain name resolution. After the target DNS server completes the domain name resolution of the target domain name, the target DNS server can feed back the resolution result to the proxy server, so that the proxy server can forward the target data access request to the target origin site pointed to by the resolution result, and the proxy server can also target The source site’s response results update the target historical resolution records, so that the values recorded in the target historical resolution records can reflect the latest resolution status of each DNS server, which can be used as a basis for the next resolution of the target domain name. It can not only ensure the maximum use of existing resources, but also ensure that users' access requests can be responded to in a timely manner.

The technical solution provided by this application forwards the user's access request by introducing a proxy server, and the proxy server can select the forwarding path to ensure the transmission rate of the access request and the control of operating costs.

Description of the drawings

In order to more clearly describe the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings that need to be used in the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work.

FIG. 1 is a schematic diagram of the architecture of a DNS server selection system in an embodiment of the present application;

FIG. 2 is a flowchart of a method for selecting a DNS server in Embodiment 1 of the present application;

Fig. 3 is a schematic diagram of functional modules of a DNS server selection device in an embodiment of the present application;

Fig. 4 is a schematic diagram of the structure of a proxy server in an embodiment of the present application.

Detailed ways

In order to make the purpose, technical solutions, and advantages of the present application clearer, the embodiments of the present application will be described in detail below with reference to the accompanying drawings.

With the rapid development of the Internet, the network environment is becoming more and more complex. Various factors such as interoperability, regional ISP limitations, and limited export bandwidth have caused the regional inaccessibility of the website. Therefore, the traditional centralized deployment of resource nodes can no longer satisfy users. In order to ensure that users in different regions can get a good experience when visiting the website, many content providers will adopt a distributed deployment method, deploying resource nodes in different regions, which also leads to the existence of the same domain name in different locations. There are multiple source stations in a region, and the network cost is different in different regions. To reduce network costs and consider disaster tolerance, operators usually deploy multiple DNS servers. For example, operators can deploy DNS server No. 1 for resource nodes in the northern region, and DNS server No. 2 for resource nodes in the southern region. The origin site IP obtained through the resolution of different DNS servers is generally different. For example, when the DNS server No. 1 is selected to be responsible for domain name resolution, the origin site deployed in the northern region can be preferentially directed. In practical applications, the user usually sets the default DNS server locally. For example, the user's domain name resolution request is dispatched to an area where the network cost is relatively cheap. The resolution result obtained after the DNS server resolves contains the IP address of the source site, and the default DNS server feedback The source station corresponding to the source station IP is usually a closer physical distance from the requesting end, or a resource node of the same operator.

However, the existing prioritized use of the default DNS server to respond to the user’s domain name resolution request has a problem in the background technology. Therefore, how to select a suitable DNS server for the data access request according to the response of the origin site, and then ensure that the user sends it Every data access request of the company can get a response from the source site in time, which has become an urgent issue in this field.

The technical solution provided by this application can solve the above-mentioned shortcomings.

In order to facilitate understanding, the proxy server involved in this application is briefly introduced.

A proxy server is a transfer station for network information, which can obtain network information on behalf of users. Its most basic function is connection. In addition, it also includes functions such as security, caching, content filtering, and access control management. A complete proxy request process is: the client first establishes a connection with the proxy server, and then according to the proxy protocol used by the proxy server, it requests to establish a connection to the target server, or obtain the specified resources of the target server, or use NAT (Network Address Translation) , Network address translation) technology to implement the transparent proxy, the request sent by the client to the source station is redirected to the proxy server by its network exit device or local proxy program, and the proxy server processes the request and passes the response result through the original The path is fed back to the client.

The network exit device includes the routing device for the user to access the Internet. Generally speaking, the data traffic sent by the user will pass through the network exit device and finally reach the destination server.

Please refer to FIG. 1, which is a schematic diagram of the architecture of the DNS server selection system in an embodiment of this application.

In this embodiment, the DNS server selection system includes at least one requester (user A, B), a proxy server, a default DNS server and an alternative DNS server, and an origin site corresponding to the default DNS server and the alternative DNS server respectively. S1 and source station S2. All data access requests sent by users will be directed to the proxy server, which is responsible for data interaction with the source site. Specifically, the DNS server selection system can direct the data access request sent by the user to the proxy server through traffic mirroring or policy routing. The proxy server locally maintains a historical resolution record. The historical resolution record records the relevant resolution record value of each domain name received by the proxy server, which specifically includes the domain name information, the number of abnormal results, and the DNS server type.

In one embodiment, a DNS server list can be created in the configuration file of the proxy server, and multiple DNS servers are recorded in order in the above DNS server list, and the priority of each DNS server can be in accordance with the order in which it is arranged in the DNS server list. Determine, for example, set the DNS server ranked first as the default DNS server, and set the DNS server ranked second and later as alternative DNS servers. In addition, you can also set the DNS server ranked second in the DNS server list as the first candidate DNS server, and set the DNS server ranked third in the DNS server list as the second candidate DNS server. analogy. The arrangement order of each DNS server in the DNS server list can be set based on factors such as the performance of each DNS server or network cost.

It is important to point out that the number of alternative DNS servers can be set to one or multiple. When multiple DNS servers are set as alternative DNS servers, the DNS server selection system can use the polling mechanism in the above Choose between multiple DNS servers.

It is important to point out that in this application, the default DNS server and the alternative DNS server are two completely independent DNS servers. They have the same status in the network architecture and can independently respond to domain name requests, as shown in the full text. As mentioned, the operator usually deploys multiple DNS servers to resolve requests in the area. Correspondingly, among the resolution results of these DNS servers, the preferred feedback is the content server (origin site) in the area where the DNS server is located. Therefore, usually the default DNS server and the alternate DNS server maintain different domain name to IP address mapping records. Assuming that at a certain moment, both the default DNS server and the alternate DNS server are used to resolve the domain name of the same access request. The IP address of the source station resolved by the default DNS server and the alternate DNS server may be different.

Please refer to FIG. 2, which is a flowchart of a method for selecting a DNS server in Embodiment 1 of this application. The method for selecting a DNS server in this embodiment is applied to a proxy server, and the method may include the following steps.

S101: Obtain a target data access request, and parse the target data access request to obtain a carried target domain name.

In one embodiment, all data access requests sent by users in the system will be directed to the proxy server. For one of the data access requests (that is, the target data access request), when the proxy server obtains the target data access request, The proxy server may perform preliminary analysis on the target data access request to obtain the target domain name carried in the target data access request. It should be particularly pointed out that the proxy server will perform a preliminary analysis on all data access requests received to obtain the domain name information carried in each data access request.

In one embodiment, the proxy server can obtain the target data access request by receiving the target data access request sent by the user's network exit device, where the target data access request is redirected to the proxy server by the aforementioned network exit device (that is, in The network exit device intercepts user traffic and forwards it to the proxy server), and/or receives the target data access request forwarded by the local proxy (that is, the user traffic is directed to the proxy server by embedding the SDK in the client).

In one embodiment, the proxy server parses the target domain name carried in the target data access request can be implemented in the following manner. The proxy server parses the URI (Uniform Resource Identifier, Uniform Resource Identifier) from the data message corresponding to the target data access request. Identifier), and then determine the target domain name from the resolved URI. Usually a data access request is composed of multiple data messages. Taking the http protocol as an example, an http data access request includes at least a TCP connection request message, a data request message including a URI, etc. When the proxy server receives http data After the access request, the proxy server can parse out the data request message containing the URI in the data message, and then parse the data request message containing the URI to obtain the target domain name carried therein.

S102: Determine a target DNS server from the default DNS server and the at least one candidate DNS server according to the target historical resolution record corresponding to the target domain name, so that the target DNS server resolves the target domain name .

After the proxy server obtains the target domain name carried in the target data access request, the proxy server can query the historical resolution record of the target historical resolution record corresponding to the target domain name according to the target domain name, and analyze the value in the target historical record according to the target domain name. , The target DNS server is determined from the default DNS server and the at least one candidate DNS server, and then the proxy server constructs a domain name resolution request based on the target domain name and sends it to the target DNS server, so that the target DNS server performs Parsing.

In practical applications, the historical resolution record contains at least the domain name information, the number of abnormal results, and the DNS server type. Each domain name obtained by the proxy server will be recorded in the historical resolution record, and for each domain name, the historical resolution record contains the number of abnormal results corresponding to the domain name and the type of DNS server. For example, for the domain name "www.abc.com", the historical resolution record will record the type information of all DNS servers that have performed domain name resolution on www.abc.com. The type information includes at least the unique identification information of the DNS server and the DNS server The availability status of the DNS server, the load status of the DNS server, etc., and the response results corresponding to the source station resolved by each DNS server and the number of abnormal response results (that is, the number of abnormal results) are also recorded in the historical analysis record.

For example, the historical analysis record can have the structure shown in Table 1:

Table 1 (historical analysis records)

Domain name information	DNS server type	Number of abnormal results
www.abc.com	Default DNS server, available	20
www.abc.com	The first alternative DNS server, available	60
www.abc.com	The second alternative DNS server, unavailable	100
www.xy.com	Default DNS server, unavailable	80
www.xy.com	The first alternative DNS server, available	20
…	…	…

When the proxy server obtains the domain name "www.abc.com", the proxy server can query the historical analysis records corresponding to www.abc.com in the historical analysis records, that is,

www.abc.com	Default DNS server, available	20
www.abc.com	The first alternative DNS server, available	60
www.abc.com	The second alternative DNS server, unavailable	100

By parsing the values in the historical resolution records of the target, the proxy server can determine that the default DNS server and the first candidate DNS server are available, and the number of abnormal results corresponding to the default DNS server is less than the number of abnormal results corresponding to the first candidate DNS server. Therefore, the proxy server can select the default DNS server as the target DNS server for the domain name "www.abc.com", and the default DNS server will perform domain name resolution on the domain name "www.abc.com".

It should be particularly pointed out that the structure shown in Table 1 above is only an illustration, and is not a limitation on historical analysis records. Based on the idea of this application, those skilled in the art can also use other forms (such as log tables) to achieve this. Historical analysis records.

In one embodiment, according to the target historical resolution record corresponding to the target domain name, the following steps may be adopted to determine the target DNS server among the default DNS server and at least one candidate DNS server.

First, determine the target historical resolution record in the historical resolution record according to the target domain name.

Secondly, obtain the DNS server type whose number of abnormal results in the target historical analysis record does not exceed the target threshold.

Finally, based on the DNS server type and preset rules, the target DNS server is determined from the default DNS server and at least one candidate DNS server.

Since the historical resolution records record the relevant resolution record values of all domain names received by the proxy server, the proxy server can query the historical resolution records for all relevant resolution record values that contain the target domain name according to the target domain name, and based on the above query All relevant analysis record values of, determine the target historical analysis record.

After the proxy server determines the target historical resolution record, the proxy server can obtain the number of abnormal results corresponding to each DNS server from the historical resolution record of the target, and then determine the record item whose abnormal number does not exceed the target threshold, and then from the above record items The corresponding DNS server type is queried, and based on the queried DNS server type and preset rules, the target DNS server is determined from the default DNS server and the at least one candidate DNS server.

Continuing to take Table 1 as an example, after the proxy server finds the target historical resolution record corresponding to www.abc.com in the historical resolution record, it can obtain from the target historical resolution record that the number of abnormal results corresponding to the default DNS server is 20. The number of abnormal results corresponding to one candidate DNS server is 60, and the number of abnormal results corresponding to the second candidate DNS server is 100. Assuming the target threshold is 80, then the proxy server can determine that the record items whose abnormal results do not exceed 80 are included The record item of the default DNS server type, and the record item containing the first candidate DNS server type. If the preset rule is to first determine the available status of the DNS server, if all are available, then determine the number of abnormal results, and select the DNS server with a small number of abnormal results as the target DNS server, then the proxy server will follow the records in the DNS server type, First, it can be determined that both the default DNS server and the first candidate DNS server are available, and then it is determined that the number of abnormal results corresponding to the default DNS server is less than the number of abnormal results corresponding to the first candidate DNS server. Therefore, the proxy server will select the default DNS server As the target DNS server for www.abc.com. Generally speaking, when configuring the DNS server, the selection of the default DNS server will be confirmed based on factors such as network cost and quality. Therefore, the default DNS server is often a better choice. In other embodiments of this application, preset rules may also be used. Include When the default DNS server is included in the available DNS servers, the default DNS server is preferred.

S103: Receive the resolution result fed back by the target DNS server, and send the target data access request to the target source station pointed to by the resolution result, and update the target historical resolution based on the response result of the target source station record.

In one embodiment, after the target DNS server successfully completes the domain name resolution work of the target domain name, the resolution result of the target domain name can be obtained. The resolution result is usually the address information of a certain source station that provides resource services for the target domain name, including IP address. The target DNS server will feed back the above analysis result to the proxy server. After the proxy server receives the analysis result fed back by the target DNS server, the proxy server can send the target data access request to the source represented by the above IP address according to the address information in the analysis result. Station (that is, the target source station). Specifically, the proxy server can determine the data information requested by the user by analyzing each request message contained in the target data access request, and encapsulate a new access request based on the data information and the address information of the source station, and send it to Source station.

When the proxy server sends the target data access request to the target source site, the target source site will feedback the response data to the proxy server. After the proxy server receives the above response data, it can obtain the response status code through the header information of the response data, and according to The above response status code determines whether the target source station can respond normally. If the response status code is "5xx" (server error), such as "500", "503" and other information, the proxy server can determine that the target source station responds abnormally, and the source station cannot feed back the requested data normally. If the response status code is "2xx" (success), such as "200", "201" and other information, the proxy server can determine that the target source station responds normally, and the proxy server will receive the request data and target data fed back by the source station Access the data resource pointed to by the request. After the proxy server obtains the response result of the target source station, it can update the target historical analysis record according to the response result of the target source station.

In one embodiment, based on the response result of the target source station, updating the target historical analysis record may include the following steps.

First, determine whether the response result is normal. If so, reset the number of abnormal results corresponding to the target source station; if not, accumulate the number of abnormal results corresponding to the target source station.

When the proxy server knows the response status code through the header information of the response data, it can judge whether the target source station can respond normally according to the above response status code. If the proxy server judges that the target source station can respond normally (that is, the response result is normal), then the proxy The server can reset the number of abnormal results corresponding to the target source station to zero, or reduce the number of abnormal results by 1. If the proxy server determines that the target source station cannot respond normally (that is, the response result is abnormal), then the proxy server can reset the target source station The corresponding number of abnormal results plus one. Through the response results of the target source site, the number of abnormal results in the historical analysis record of the target is updated, which can indirectly monitor the working status of the target DNS server corresponding to the target source site. For example, the proxy server can be set when the result is abnormal. After the number of times exceeds the specified value, the working state of the corresponding DNS server is adjusted to be unavailable, or, when the number of abnormal results is less than the specified value, the working state of the corresponding DNS server is adjusted to be available.

In practical applications, in addition to the source station’s own reasons that cause the proxy server to judge the source station’s response abnormally, such as the source station’s address information has been updated or the source station’s failure, there may also be factors such as network congestion that cause the proxy server to judge the source The station responds abnormally. For example, the source station can respond normally, but the proxy server judges that the source station's response is timed out due to network congestion. At this time, the proxy server will also judge that the source station's response is abnormal. Therefore, the proxy server can adjust the number of abnormal results according to the number of continuous responses from the source station.

In one embodiment, when the proxy server determines that the target source station responds normally, the proxy server may set the number of abnormal results corresponding to the target source station to zero. When the proxy server determines that the target source station responds abnormally, the proxy server may set the target source station to respond abnormally. The number of abnormal results corresponding to the station is the sum of the current value and the specified positive integer. For example, the proxy server sends the corresponding nth data access request to the target source station according to the nth domain name resolution result of the target domain name fed back by the DNS server, and when it is judged that the nth data access request is a normal response from the target source station After that, the proxy server can set the number of abnormal results corresponding to the target source site to zero, and then the proxy server sends the corresponding n+1th data access request according to the n+1th domain name resolution result of the target domain name fed back by the DNS server To the target source site, after judging that the n+1th data access request obtains an abnormal response from the target source site, the proxy server can set the number of abnormal results corresponding to the target source site to 1, and then the proxy server continues to follow the target feedback from the DNS server The n+2th domain name resolution result of the domain name, the corresponding n+2th data access request is sent to the target source site. After judging that the n+2th data access request obtains an abnormal response from the target source site, the proxy server can Set the number of abnormal results corresponding to the target source station to 2, and so on. Through the above method, only when the proxy server judges that the target domain name is continuously unable to obtain the normal response of the target source station, the number of abnormal results corresponding to the target source station will increase, which can reduce the proxy server judgment due to network congestion and other factors to a certain extent. The source station responds abnormally, and the number of abnormal results can more truly reflect the working status of the target source station.

In practical applications, the concurrent traffic on the proxy server is constantly changing. If the target threshold is set to a fixed value, the proxy server will not be able to adjust the DNS server selection conditions according to the actual load. For example, if the target threshold is set to 100, and the concurrent traffic of the proxy server reaches 3000 at a certain time, the number of abnormal results of the target domain name may reach 100 in a short time, and the proxy server will check the available status of the currently used DNS server Adjust to unavailable, and then select other DNS servers for subsequent resolution of the target domain name. In fact, the currently used DNS server still has not reached the maximum load, and it can still continue to perform domain name resolution on other domain names. Therefore, the proxy server can also dynamically adjust the target threshold according to the concurrent traffic.

In an embodiment, the proxy server may also set an initial threshold in advance, calculate the adjustment threshold according to the concurrent traffic in the update period and a preset proportional coefficient, and then generate the target threshold according to the initial threshold and the adjustment threshold. For example, the proxy server sets the initial threshold to 100 and the preset scale factor to 0.1 based on experience. If the concurrent traffic of the proxy server reaches 3000 at a certain moment, the proxy server can calculate the adjustment threshold to be 300 and set the target The threshold is set to 400; if the concurrent traffic of the proxy server reaches 1000 at a certain moment, the proxy server can calculate the adjustment threshold to be 100 and set the target threshold to 200. To prevent the proxy server from frequently adjusting the target threshold, the proxy server can also set trigger conditions for adjusting the target threshold. For example, the adjustment threshold is calculated only when the concurrent traffic exceeds 1000, and the target threshold is reset; or every 10 minutes, the current proxy is taken Concurrent traffic value on the server, calculate the adjustment threshold, and reset the target threshold.

It should be pointed out that the proxy server can set the same initial threshold for all domain names, or set different initial thresholds for different domain names. Correspondingly, the proxy server can set the same preset scale factor for all domain names. Different preset ratio coefficients can be set for different domain names, which is not limited in this application.

In practical applications, the default DNS server set by the operator can dispatch the user's data access request to an area where the network cost is relatively cheap. Therefore, when the DNS server selection system is used for the first time, the default DNS server can be set to resolve all data access requests. When the DNS server selection system is used for the first time, no domain name is usually recorded in the historical resolution records. Therefore, for all data access requests sent by users, the proxy server will use the default DNS server to resolve the above data access requests, and according to The response result of the target origin site updates the historical resolution records of each domain name.

In one embodiment, the proxy server may update the historical analysis record based on active detection, which specifically includes the following steps.

First, determine the domain name and the corresponding DNS server with the number of abnormal results in the historical analysis record greater than the detection threshold as the domain name to be detected and the DNS server to be detected.

Then, a first detection message is constructed based on the domain name to be detected, and sent to the corresponding DNS server to be detected to obtain the resolution result.

Finally, a second detection message is constructed based on the analysis result and sent to the source station pointed to by the analysis result, and the historical resolution record corresponding to the DNS server to be detected is updated according to the response result of the source station.

The proxy server can set the detection threshold, and query all the domain names with abnormal times greater than the detection threshold in the historical analysis records, and determine the corresponding DNS server, and then mark the queried domain name and the corresponding DNS server as the domain name to be detected and the domain name to be detected. DNS server.

After determining the domain name to be detected and the DNS server to be detected, the proxy server may construct a first detection message based on the domain name to be detected. The first detection message carries the domain name to be detected, and then sends the first detection message to the corresponding domain name to be detected. Detecting the DNS server. After the DNS server to be detected resolves the domain name to be detected in the first detection message, the domain name resolution result can be obtained. The domain name resolution result is usually the IP address of a certain source station that provides access services for the domain name to be detected .

After the proxy server receives the domain name resolution result fed back by the DNS server to be detected, the proxy server can construct a second detection message based on the above analysis result, and the second detection message carries the information of the source station that provides access services for the domain name to be detected. IP address, and then the proxy server sends the above-mentioned second detection message to the source station, and according to the response result of the source station, updates the historical resolution record corresponding to the DNS server to be detected.

Continuing to take Table 1 as an example, suppose the proxy server sets the detection threshold to 90. The proxy server can determine that the domain name with abnormal results greater than 90 is: www.abc.com, and its corresponding DNS server is the second backup. Select the DNS server, so the proxy server marks www.abc.com as the domain name to be detected, and marks the second candidate DNS server as the DNS server to be detected. Then the proxy server constructs a first detection message containing "www.abc.com" information, and sends the first detection message to the second candidate DNS server, and the second candidate DNS server pairs www.abc.com Perform analysis to obtain the IP address of the source site that provides access to www.abc.com. After the second candidate DNS server obtains the IP address of the source site that provides access services for www.abc.com, the second candidate DNS server will feed back the above IP address to the proxy server so that the proxy server can construct the IP address containing the above IP Address of the second detection message, the proxy server can send the above-mentioned second detection message to the source station represented by the IP address. After receiving the second detection message, the source station can feedback response data to the proxy server, and the proxy server can send the response data to the proxy server according to The status code in the response data determines whether the source station can respond normally. If the source station can respond normally (that is, the response result is normal), the proxy server can reset the number of abnormal results corresponding to the second candidate DNS server to zero (that is, by Update 100 to 0), or reduce the number of abnormal results by 1 (that is, update from 100 to 99); if the proxy server determines that the source station cannot respond normally (that is, the response result is abnormal), then the proxy server can change the second candidate DNS The number of abnormal results corresponding to the server is increased by 1 (that is, updated from 100 to 101).

In addition, the proxy server can also update the working status of the DNS server according to the number of abnormal results. Continuing to take Table 1 as an example, assuming that the proxy server sets the DNS server to be available when the number of abnormal results is less than 70, then the proxy server updates the number of abnormal results corresponding to the second candidate DNS server according to the response results of the source site. When the updated number of abnormal results becomes 69, the proxy server will update the working status of the second candidate DNS server to "available".

In one embodiment, after the proxy server determines the domain name and the corresponding DNS server whose number of abnormal results in the historical analysis record is greater than the detection threshold, as the domain name to be detected and the DNS server to be detected, the proxy server can also set each domain name to be detected The same/different detection period, so that the proxy server constructs the first detection message based on the detection period corresponding to each domain name to be detected.

Continuing to take Table 1 as an example, suppose the domain name 1 to be detected is www.abc.com, its corresponding DNS server is the second candidate DNS server, the domain name 2 to be detected is www.xy.com, and its corresponding DNS server is the default DNS server, then the proxy server can set the detection period for www.abc.com and www.xy.com respectively. The length of the detection period can be the same or different. The proxy server is based on www.abc.com and www.xy.com. In the detection cycle, the first detection message is constructed for www.abc.com and www.xy.com respectively, and the first detection message of www.abc.com is sent to the second candidate DNS server, and www.xy.com is sent to the second candidate DNS server. The first detection message of com is sent to the default DNS server, so as to update the historical resolution records corresponding to the second candidate DNS server and the default DNS server according to the response result of the source station.

By setting the detection period for each domain name to be detected, the proxy server can actively detect each DNS server to be detected periodically, so as to update the working status of each DNS server to be detected in time.

In an embodiment, after the proxy server receives the response data fed back by the target source station, the proxy server may respond to the target data access request based on the response result. Specifically, when the proxy server sends response data to the user, it can construct a data packet based on the response result of the source station, using the user's address as the destination address, and send the data packet to the user; or, the proxy server can follow the original receiving path Return, and the export device or local agent will convert the address, and change the source address of the response packet to the original destination address and the destination address to the original source address.

Please refer to FIG. 3, this application also provides a DNS server selection device, the device is applied to a proxy server, the proxy server is set with a default DNS server and at least one candidate DNS server, and stores historical resolution records , The device includes the following modules.

The data receiving module is used to obtain the target data access request, and parse the target domain name carried from the target data access request.

The DNS selection module is configured to determine a target DNS server among the default DNS server and the at least one candidate DNS server according to the target historical resolution record corresponding to the target domain name, so that the target DNS server can The target domain name is resolved.

The resolution record update module is used to receive the resolution result fed back by the target DNS server, and send the target data access request to the target source station pointed to by the resolution result, and update based on the response result of the target source station The target historical analysis record.

In an embodiment, the historical resolution record includes at least domain name information, number of abnormal results, and DNS server type.

In one embodiment, determining the target DNS server among the default DNS server and the at least one candidate DNS server according to the target historical resolution record corresponding to the target domain name includes the following steps: Determine the target historical resolution record in the historical resolution record; obtain the DNS server type whose number of abnormal results in the target historical resolution record does not exceed the target threshold; based on the DNS server type and preset rules, in the default DNS server and the The target DNS server is determined among the at least one candidate DNS server.

In one embodiment, based on the response result of the target source station, updating the target historical analysis record includes: judging whether the response result is normal, and if so, resetting the number of abnormal results corresponding to the target source station ; If not, accumulate the number of abnormal results corresponding to the target source station.

In one embodiment, the device further includes: a threshold setting module, configured to set an initial threshold, and calculate an adjustment threshold according to the concurrent traffic in the update period and a preset proportional coefficient, and according to the initial threshold and the adjustment threshold The target threshold is generated.

In an embodiment, the device further includes: an active detection module, configured to determine the domain name and the corresponding DNS server whose number of abnormal results in the historical analysis record is greater than the detection threshold, as the domain name to be detected and the DNS server to be detected; And construct a first detection message based on the domain name to be detected and send it to the corresponding DNS server to be detected to obtain a resolution result; and construct a second detection message based on the resolution result and send it to the resolution The result points to the source station, and according to the response result of the source station, the historical resolution record corresponding to the DNS server to be detected is updated.

4, the present application also provides a proxy server, the proxy server includes a memory and a processor, the memory is used to store a computer program, when the computer program is executed by the processor, can achieve as described above DNS server selection method. Specifically, at the hardware level, the data conversion server may include a processor, an internal bus, and a memory. The memory may include memory and non-volatile memory. The processor reads the corresponding computer program from the non-volatile memory into the memory and then runs it. Those of ordinary skill in the art can understand that the structure shown in FIG. 4 is only for illustration, and it does not limit the structure of the proxy server described above. For example, the proxy server may also include more or fewer components than shown in FIG. 4, for example, may also include other processing hardware, such as a GPU (Graphics Processing Unit, image processor), or an external communication port. Of course, in addition to software implementation, this application does not exclude other implementations, such as logic devices or a combination of software and hardware, and so on.

In this embodiment, the processor may include a central processing unit (CPU) or a graphics processing unit (GPU), of course, may also include other single-chip microcomputers, logic gate circuits, integrated circuits, etc. with logic processing capabilities, or appropriate combination. The memory described in this embodiment may be a memory device for storing information. In a digital system, a device that can store binary data can be a memory; in an integrated circuit, a circuit with storage function without physical form can also be a memory, such as RAM, FIFO, etc.; in a system, it has physical storage The device can also be called a memory and so on. When implemented, the memory may also be implemented in the form of cloud storage, and the specific implementation manner is not limited in this specification.

It should be noted that, for the specific implementation of the proxy server in this specification, reference may be made to the description of the method embodiment, which will not be repeated here.

It can be seen that, in the technical solution provided by this application, the default DNS server and at least one alternative DNS server can be preset in the proxy server, and the historical resolution records of each domain name can be stored. When the proxy server receives the target from the user After the target data access request of the domain name, the target historical resolution record corresponding to the target domain name can be queried in the stored historical resolution records, and then according to the value recorded in the target historical resolution record, the default DNS server and at least one backup The target DNS server is determined from the selected DNS server, and the target DNS server performs domain name resolution on the target domain name. After the target DNS server completes the domain name resolution of the target domain name, the target DNS server can feed back the resolution result to the proxy server, so that the proxy server can send the target data access request to the target source site pointed to by the resolution result, and the proxy server can also target The source station’s response result updates the target historical resolution record, so that the value recorded in the target historical resolution record can reflect the latest working status of each DNS server. Based on the latest working status of each DNS server, the proxy server can be Select the best DNS server for the target domain name, which can ensure the maximum use of existing resources and ensure that users' access requests can be responded to in time.

Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solution essentially or the part that contributes to the existing technology can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM/RAM, magnetic A disc, an optical disc, etc., include several instructions to make a computer device (which may be a personal computer, a server, or a network device, etc.) execute the methods described in each embodiment or some parts of the embodiment.

The above descriptions are only preferred embodiments of this application, and are not intended to limit this application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this application shall be included in the protection of this application. Within range.

Claims (11)

1. A method for selecting a DNS server, the method is applied to a proxy server, the proxy server is configured with a default DNS server and at least one candidate DNS server, and stores historical resolution records, the method includes:

   Obtaining a target data access request, and parsed from the target data access request to obtain the carried target domain name;

   Determine a target DNS server from the default DNS server and the at least one candidate DNS server according to the target historical resolution record corresponding to the target domain name, so that the target DNS server resolves the target domain name;

   Receive the resolution result fed back by the target DNS server, and send the target data access request to the target source station pointed to by the resolution result, and update the target historical resolution record based on the response result of the target source station.
2. The method according to claim 1, wherein the historical resolution record contains at least domain name information, number of abnormal results, and DNS server type.
3. The method according to claim 2, wherein, according to the target historical resolution record corresponding to the target domain name, determining the target DNS server from the default DNS server and the at least one candidate DNS server comprises:

   Determining a target historical resolution record in the historical resolution record according to the target domain name;

   Acquiring the DNS server type whose number of abnormal results in the target historical analysis record does not exceed the target threshold;

   Based on the DNS server type and preset rules, a target DNS server is determined among the default DNS server and the at least one candidate DNS server.
4. The method according to claim 2, wherein, based on the response result of the target source station, updating the target historical analysis record comprises:

   Determine whether the response result is normal, and if so, reset the number of abnormal results corresponding to the target source station;

   If not, the number of abnormal results corresponding to the target source station is accumulated.
5. The method according to claim 3, wherein the method further comprises:

   Set the initial threshold, and calculate and adjust the threshold according to the concurrent traffic in the update period and the preset proportional coefficient;

   The target threshold value is generated according to the initial threshold value and the adjustment threshold value.
6. The method according to claim 2, wherein the method further comprises:

   Determining the domain name and the corresponding DNS server with the number of abnormal results in the historical analysis record greater than the detection threshold as the domain name to be detected and the DNS server to be detected;

   Constructing a first detection message based on the domain name to be detected, and sending it to the corresponding DNS server to be detected to obtain a resolution result;

   Construct a second detection message based on the analysis result and send it to the source station pointed to by the analysis result, and update the historical resolution record corresponding to the DNS server to be detected according to the response result of the source station.
7. The method according to claim 6, wherein after determining the domain name and the corresponding DNS server whose abnormal number of results in the historical analysis record is greater than the detection threshold as the domain name to be detected and DNS server to be detected, the method further comprises:

   The same/different detection period is set for each domain name to be detected, so that the proxy server constructs the first detection message based on the detection period corresponding to each domain name to be detected.
8. The method according to claim 1, wherein the target domain name that is obtained by parsing the target data access request comprises:

   The URI is parsed from the data message corresponding to the target data access request, and the target domain name is determined from the URI.
9. The method according to claim 1, wherein obtaining the target data access request comprises:

   Receiving a target data access request sent by a user network exit device, wherein the target data access request is redirected to the proxy server by the network exit device;

   And/or receive the target data access request forwarded by the local agent.
10. The method according to claim 1, wherein the method further comprises:

    Respond to the target data access request based on the response result.
11. A proxy server, the proxy server includes a memory and a processor, the memory is used to store a computer program, when the computer program is executed by the processor, the implementation is as described in any one of claims 1 to 10 The method described.

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