CN104506665B - Distinguish method and system in a kind of IPv4/IPv6 addresses - Google Patents

Abstract

The invention provides a method and system for distinguishing IPv4/IPv6 addresses, relates to the communication field, and solves the problem of reduced user experience caused by dual-stack users accessing an IPv4 server through an IPv6 protocol stack. The method includes: the authoritative DNS receives the domain name sent by the local DNS, and according to the domain name address mapping list, obtains the IPv4 address and the IPv6 address of the corresponding domain name, wherein the IPv6 address corresponding to the domain name is the original IPv6 address or the corresponding IPv4 address added by the authoritative DNS The IPv6 address of the address, the authoritative DNS marks the added IPv6 address corresponding to the IPv4 address, and sends the IPv4 address and IPv6 address of the corresponding domain name to the local DNS; the local DNS receives the IPv4 address and IPv6 address of the corresponding domain name, and according to the user The type of the terminal and whether the IPv6 address has a flag, and the IPv4 address or the IPv6 address is sent to the user terminal. The present invention is used in the transition business of converting from IPv4 to IPv6.

Description

A method and system for distinguishing IPv4/IPv6 addresses

technical field

The invention relates to the communication field, in particular to a method and system for distinguishing IPv4/IPv6 addresses.

Background technique

In recent years, due to the lack of network addresses contained in the IPv4 network, the development of the network has been limited. The global network has an inevitable trend of transition from IPv4 to IPv6. During this process, most small and medium CP (ContentProvider, content provider )/SP (Service Provider, Service Provider) has neither the ability nor the resources to migrate to IPv6 as a whole. Therefore, the problem of IPv6 single-stack users accessing IPv4 applications is inevitable. The prior art adopts the NAT64/DNS64 system to solve the above problems. This solution deploys NAT64 at the exit of the Internet Data Center (IDC), converts IPv4 data packets into IPv6 data packets through protocol translation and sends them back to user terminals, so that IPv6 single-stack users can access IPv4 applications.

However, in NAT64 and DNS64 systems, IPv4/IPv6 dual-stack users can not only directly access IPv4 applications through the IPv4 protocol stack, but also access IPv4 applications through NAT64 translation through the IPv6 protocol stack, just like IPv6 single-stack servers. When a large number of dual-stack users access IPv4 applications through NAT64 translation through the IPv6 protocol stack, the NAT64 devices deployed at the IDC egress are occupied by a large number of dual-stack users, resulting in the inability of IPv6 single-stack users to obtain sufficient NAT64 translation services, and the translation process of NAT64 This leads to delays in the access of dual-stack users, and ultimately affects the service experience of IPv6 single-stack users and dual-stack users.

Contents of the invention

The embodiment of the present invention provides a method and system for distinguishing IPv4/IPv6 addresses to solve the problem that a large number of dual-stack users access IPv4 servers through NAT64 translation through the IPv6 protocol stack, resulting in reduced service experience of IPv6 single-stack users and dual-stack users The problem.

In order to achieve the above object, embodiments of the present invention adopt the following technical solutions:

In a first aspect, the present invention provides a method for distinguishing IPv4/IPv6 addresses, comprising the following steps:

Address marking step, the authoritative DNS receives the domain name sent by the local DNS, and obtains the IPv4 address and IPv6 address corresponding to the domain name according to the domain name address mapping list of the authoritative DNS, wherein the IPv6 address corresponding to the domain name is a native IPv6 address or The IPv6 address corresponding to the IPv4 address added by the authoritative DNS, the authoritative DNS marks the added IPv6 address corresponding to the IPv4 address, and sends the IPv4 address and IPv6 address corresponding to the domain name to the local DNS, so that The local DNS can judge whether the server corresponding to the domain name supports the IPv6 protocol stack by whether the IPv6 address corresponding to the domain name has a mark;

The address sending step, the local DNS receives the IPv4 address and IPv6 address corresponding to the domain name, and sends the IPv4 address or IPv6 address to the user terminal according to the user type and whether the IPv6 address has a mark, so as to provide the user terminal with a corresponding The address of the domain name that the user visits.

With reference to the first aspect, in a first possible implementation manner, the obtaining the IPv4 address and IPv6 address corresponding to the domain name according to the domain name address mapping list includes:

The address acquisition module queries the domain name address mapping list to obtain the IPv4 address corresponding to the domain name; and

The address acquisition module queries the domain name address mapping list, if the original IPv6 address can be found, then obtains the IPv6 address corresponding to the domain name; if the original IPv6 address cannot be found, then increases the IPv6 address corresponding to the IPv4 address, An IPv6 address corresponding to the domain name is obtained.

In combination with the first aspect and the first possible implementation manner of the first aspect, in a second possible implementation manner, according to the user type and whether the IPv6 address has a flag, sending the IPv4 address to the user terminal Addresses or IPv6 addresses include:

User type judging step, the user type judging module judges the user type according to the source address of the user, and the user type includes IPv4 single-stack users, IPv6 single-stack users, dual-stack users;

In the sending step, the sending module sends the IPv4 address or IPv6 address to the user terminal according to the judgment result of the user type judging module.

With reference to the second possible implementation manner of the first aspect, in a third possible implementation manner, when the user type judging module judges that the user type is a dual-stack user, the sending step specifically includes:

If the IPv6 address corresponding to the domain name has a mark, sending the IPv4 address corresponding to the domain name to the user terminal;

If the IPv6 address corresponding to the domain name does not have a flag, sending the IPv6 address corresponding to the domain name to the user terminal.

With reference to the first possible implementation manner of the first aspect, in a fourth possible implementation manner, the marking the IPv6 address corresponding to the IPv4 address added by the authoritative DNS specifically includes:

Setting at least one bit of the IPv6 address corresponding to the IPv4 address added by the authoritative DNS as a flag value.

With reference to the second possible implementation manner of the first aspect, in a fifth possible implementation manner, the specific methods adopted in the step of determining the user type include:

By pre-storing the IP address range of the dual-stack users, judging the user type; and

By interacting with the access authentication device, the user type is judged according to the source IPv6 address of the user making the IPv6 resolution request.

With reference to the fifth possible implementation manner of the first aspect, in a sixth possible implementation manner, a specific definition of the access authentication device is provided, including:

Broadband remote access server BRAS, remote user dial-up authentication system RADIUS.

In a second aspect, the present invention provides a system for distinguishing IPv4/IPv6 addresses, including:

The authoritative DNS is used to receive the domain name sent by the local DNS, and obtain the IPv4 address and IPv6 address corresponding to the domain name according to the domain name address mapping list of the authoritative DNS, wherein the IPv6 address corresponding to the domain name is a native IPv6 address or an authoritative DNS address. The IPv6 address corresponding to the IPv4 address added by the DNS, the authoritative DNS marks the added IPv6 address corresponding to the IPv4 address, and sends the IPv4 address and IPv6 address corresponding to the domain name to the local DNS, so that the local DNS can judge whether the server corresponding to the domain name supports the IPv6 protocol stack by whether the IPv6 address corresponding to the domain name has a mark;

A local DNS, connected to the authoritative DNS, used to receive the IPv4 address and IPv6 address corresponding to the domain name, and send the IPv6 address or IPv4 address to the user terminal according to the user type and whether the IPv6 address has a mark , to provide the user terminal with the address corresponding to the domain name accessed by the user.

With reference to the second aspect, in a first possible implementation manner, the authoritative DNS includes:

Address acquisition module for

Querying the domain name address mapping list to obtain the IPv4 address corresponding to the domain name; and

Query the domain name address mapping list, if the original IPv6 address can be queried, the IPv6 address corresponding to the domain name is obtained; if the original IPv6 address cannot be queried, the IPv6 address corresponding to the IPv4 address is added to obtain the corresponding IPv6 address. IPv6 address of the above domain name.

With reference to the second aspect and the first possible implementation manner of the second aspect, in the second possible implementation manner, the local DNS includes:

User type judging module, for judging the user type according to the source address of the user, the user type includes IPv4 single-stack user, IPv6 single-stack user, dual-stack user;

The sending module is connected with the user type judging module, and is used to send the IPv4 address or IPv6 address to the user terminal according to the judgment result of the user type judging module.

With reference to the first possible implementation manner of the second aspect, in a third possible implementation manner, the authoritative DNS includes:

A marking module, connected to the address acquisition module, configured to set at least one bit of the IPv6 address corresponding to the IPv4 address added by the authoritative DNS as a marking value.

The embodiment of the present invention provides a method and system for distinguishing IPv4/IPv6 addresses, by marking the IPv6 addresses added by the authoritative DNS, to identify servers that only support the IPv4 protocol stack (the server only has native IPv4 addresses) and supports both A server of the IPv4 protocol stack and the IPv6 protocol stack (the server has a native IPv4 address and an IPv6 address). When a user terminal visits a domain name, according to the type of the user terminal and whether the IPv6 address corresponding to the domain name it visits has a flag, an IPv4 address or an IPv6 address is sent to the user terminal. Therefore, the embodiment of the present invention reasonably provides the address under the domain name for the user according to the user type and the protocol stack supported by the server accessed by the user, so as to avoid the meaningless translation process when the dual-stack user accesses the IPv4 server (i.e., through the NAT64 device) The mutual translation process of IPv4 data packets and IPv6 data packets), so as to not only reduce the access delay of dual-stack users, but also provide sufficient NAT64 translation services for single-stack users, and finally improve the service experience of users.

Description of drawings

Fig. 1 is the schematic flowchart of the IPv6/IPv4 address distinguishing method that the embodiment of the present invention provides;

Fig. 2 is a schematic flow chart of a specific method for obtaining an IPv4 address and an IPv6 address provided by an embodiment of the present invention;

FIG. 3 is a schematic flow chart of a specific method of the address sending step provided by an embodiment of the present invention;

Fig. 4 is a schematic flowchart of a specific method for marking the non-native IPv6 address IPv6 address provided by the embodiment of the present invention.

FIG. 5 is a schematic diagram of an IPv6/IPv4 address distinguishing system provided by an embodiment of the present invention;

FIG. 6 is a schematic diagram of an authoritative DNS provided by an embodiment of the present invention;

FIG. 7 is a schematic diagram of a local DNS provided by an embodiment of the present invention;

FIG. 8 is a schematic diagram of another authoritative DNS provided by an embodiment of the present invention.

detailed description

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

The method and system for distinguishing IPv4/IPv6 addresses according to the embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings.

The embodiment of the present invention provides a kind of IPv4/IPv6 address distinguishing method, as shown in Figure 1, comprises the following steps:

100. The address marking step, the authoritative DNS receives the domain name sent by the local DNS, and obtains the IPv4 address and IPv6 address corresponding to the domain name according to the domain name address mapping list of the authoritative DNS, wherein the IPv6 address corresponding to the domain name is a native IPv6 address or the IPv6 address corresponding to the IPv4 address added by the authoritative DNS, the authoritative DNS marks the added IPv6 address corresponding to the IPv4 address, and sends the IPv4 address and IPv6 address corresponding to the domain name to the local DNS, To enable the local DNS to determine whether the server corresponding to the domain name supports the IPv6 protocol stack by whether the IPv6 address corresponding to the domain name has a mark.

In this step, the local DNS extracts the domain name from the IPv4 resolution request and IPv6 resolution request sent by the user, and performs a recursive query through the domain name authority system to obtain the IPv4 address and IPv6 address corresponding to the domain name.

It should be noted that in the domain name authorization system, when the corresponding relationship between the domain name of this visit and the IPv4/IPv6 address can be queried from the domain name address mapping list of a certain DNS server, it is determined that the DNS server is the address of this visit. Authoritative DNS.

200. Address sending step, the local DNS receives the IPv4 address and IPv6 address corresponding to the domain name, and sends the IPv4 address or IPv6 address to the user terminal according to the user type and whether the IPv6 address has a mark, so as to serve as the user terminal Provide the address corresponding to the domain name accessed by the user.

In this step, the local DNS is generally a dual-stack DNS, and the dual-stack user can be identified according to the IP address range of the dual-stack user pre-stored by the dual-stack DNS, and it can also interact with the relevant server to query whether the current user is a dual-stack user. stack user.

The embodiment of the present invention provides a method for distinguishing IPv4/IPv6 addresses, by marking the IPv6 addresses added by the authoritative DNS, to identify servers that only support the IPv4 protocol stack (the server only has a native IPv4 address) and simultaneously support the IPv4 protocol stack and the server of the IPv6 protocol stack (the server has a native IPv4 address and an IPv6 address). When a user terminal visits a domain name, according to the type of the user terminal and whether the IPv6 address corresponding to the domain name it visits has a flag, an IPv4 address or an IPv6 address is sent to the user terminal. Therefore, the embodiment of the present invention reasonably provides the address under the domain name for the user according to the user type and the protocol stack supported by the server accessed by the user, so as to avoid the meaningless translation process when the dual-stack user accesses the IPv4 server (i.e., through the NAT64 device) The mutual translation process of IPv4 data packets and IPv6 data packets), so as to not only reduce the access delay of dual-stack users, but also provide sufficient NAT64 translation services for single-stack users, and finally improve the service experience of users.

In another implementation mode in the embodiment of the present invention, a specific method flow for realizing the above-mentioned acquisition of an IPv4 address and an IPv6 address is provided. The method flow is shown in FIG. 2 , including:

110. The address obtaining module queries the domain name address mapping list to obtain the IPv4 address corresponding to the domain name.

As mentioned above, there is a mapping relationship between the domain name accessed by the user and its address in the domain name address mapping list of the authoritative DNS, so this step makes the authoritative DNS query the domain name in the address mapping list to obtain the server corresponding to the domain name IPv4 address.

120. The address obtaining module queries the domain name address mapping list, and if the native IPv6 address can be found, then obtains the IPv6 address corresponding to the domain name; if the native IPv6 address cannot be found, then increases the IPv6 address corresponding to the IPv4 address address to obtain the IPv6 address corresponding to the domain name.

In this step, if the server corresponding to the domain name is a server that only supports the IPv4 protocol stack, then there is no IPv6 address corresponding to the domain name in the authoritative DNS, so the authoritative DNS converts the IPv4 address obtained in step 110 to An IPv6 address corresponding to the IPv4 address is added, and if the server corresponding to the domain name supports both the IPv4 protocol stack and the IPv6 protocol stack, the authoritative DNS directly queries the original IPv6 address from the domain name address mapping list.

In addition, the composition of the IPv6 address corresponding to the IPv4 address added by the authoritative DNS is: custom prefix + ServerIPv4 address.

In another implementation manner among the embodiments of the present invention, a specific method flow for realizing step 200 is provided, as shown in FIG. 3 , including

210. The user type judging step. The user type judging module judges the user type according to the user's source address, and the user type includes IPv4 single-stack users, IPv6 single-stack users, and dual-stack users.

It should be noted that the user's source address can be determined when the user sends an IPv4/IPv6 resolution request to the local DNS.

220. In the sending step, the sending module sends the IPv4 address or IPv6 address to the user terminal according to the judgment result of the user type judging module.

It is worth noting that according to the different types of users and whether the IPv6 address has a mark, different addresses are sent accordingly, so as to provide users with the most reasonable address type according to the protocol stack supported by the server corresponding to the domain name, the specific judgment and division process It will be introduced in detail in the specific method flow of step 220 below.

In a specific embodiment of the present invention, when the user type judging module judges that the user type is a dual-stack user, a specific method flow for implementing step 220 is provided, including:

If the IPv6 address corresponding to the domain name has a mark, sending the IPv4 address corresponding to the domain name to the user terminal;

If the IPv6 address corresponding to the domain name does not have a flag, sending the IPv6 address corresponding to the domain name to the user terminal.

In this step, because in step 100, only the IPv6 address added by the authoritative DNS is marked, and the original IPv6 address is not marked. In other words, if the IPv6 address under a domain name has a mark, indicating that the IPv6 address is converted from a native IPv4 address, the server under the domain name cannot be directly accessed through the IPv6 protocol stack; and if the IPv6 address under a domain name If there is no mark, it means that the IPv6 address is the original IPv6 address under the domain name, and the server under the domain name can be directly accessed through the IPv6 protocol stack. The stack user provides an address type that can be directly accessed (that is, if the above-mentioned IPv6 address corresponding to the domain name has a mark, then send the IPv4 address corresponding to the domain name to the user terminal; if the IPv6 address corresponding to the domain name If the IPv6 address does not have a tag, the IPv6 address corresponding to the domain name is sent to the user terminal).

It should be noted that, if the user type is a single-stack user, the IPv4 address or IPv6 address corresponding to its protocol stack is directly provided to the user.

In another embodiment of the present invention, a specific method flow for marking the IPv6 address corresponding to the IPv4 address added by the authoritative DNS is provided. The method flow is shown in FIG. 4 , including:

130. Set at least one bit of the IPv6 address added by the authoritative DNS corresponding to the IPv4 address as a flag value.

In this step, the IPv6 address has 128 bits, the first X bits are the network domain, identifying the network where the host is located, and the last 128-X bits are the host domain, identifying the address of the host. The size of X is determined manually, and commonly used X values include 48, 56, 64, etc. To make a special mark on the IPv6 address, at least one bit of the network domain or the host domain can be set as a mark value, so that the IPv6 address has a special mark and can be identified in the subsequent process.

In a specific embodiment of the present invention, a specific way of identifying user types is provided, for example:

Determine the user type by pre-storing the IP address range of the dual-stack user; or

By interacting with the access authentication device, the user type is judged according to the source IPv6 address of the user making the IPv6 resolution request.

In this step, the user-side DNS can pre-store the IPv6 address segment of the dual-stack user and the IPv6 single-stack user (the address segment generated through unified planning during the construction of the metropolitan area network), and determine by querying the address segment where the user's IPv6 source address is located. Type of user (dual-stack user or IPv6 single-stack user).

In another specific embodiment of the present invention, a specific definition of access authentication equipment is provided, including:

Broadband remote access server BRAS, remote user dial-up authentication system RADIUS.

The user-side DNS close to the user is often a dual-stack DNS, which is usually reachable with the IP route of the BRAS device and RADIUS device (storing user source address and user type) of the MAN. The provided source address information is exchanged with the BRAS device and the RADIUS device to query and obtain the user type.

Example 1

1. The authoritative DNS of the MAN of Z city receives the domain name sent by the local DNS of user A, which corresponds to the China Unicom website server.

2. The authoritative DNS queries the IPv4 address corresponding to the domain name from the domain name address mapping list. If there is no IPv6 address corresponding to the domain name, the authoritative DNS converts the IPv4 address and IPv4/IPv6 address to generate a corresponding IPv6 address. The composition of the IPv6 address is: prefix+Server IPv4 address.

3. The authoritative DNS sets the 57th-64th bits of the IPv6 address to 10101010 to obtain the corresponding IPv4 address and IPv6 address of the China Unicom website server, and sends the corresponding IPv4 address and IPv6 address of the China Unicom website server to the local DNS;

4. The local DNS receives the IPv4 address and IPv6 address corresponding to the China Unicom website server, and interacts with the BRAS device and RADIUS device, uses the source address information of user A to query the user type of A, and judges that A is a dual-stack user;

5. The local DNS judges whether the IPv6 address corresponding to the China Unicom website server has a mark, and confirms that the IPv6 address has a mark, indicating that the IPv6 address is not a native IPv6 address, that is, the server of the China Unicom website only supports the IPv4 protocol stack;

6. The local DNS returns the IPv4 address corresponding to the China Unicom website server to A, so that A can directly access the China Unicom website through the IPv4 protocol stack without translation through the NAT64 device.

Example 2

1. The authoritative DNS of the MAN of Y city receives the domain name sent by the local DNS of user B, which corresponds to the China Unicom website server.

2. The authoritative DNS obtains the original IPv4 address and IPv6 address from the China Unicom website server, and sends the corresponding IPv4 address and IPv6 address of the China Unicom website server to the local DNS.

3. The local DNS queries the IPv6 address segment of the dual-stack user and the IPv6 single-stack user planned during the construction of the MAN, and compares the IPv6 source address of user B with the above address segment, and determines that user B is a dual-stack user;

4. The local DNS judges whether the IPv6 address corresponding to the China Unicom website server has a mark, and determines that the IPv6 address does not have a mark, indicating that the IPv6 address is a native IPv6 address, that is, the China Unicom website server supports the IPv6 protocol stack;

5. The local DNS returns the IPv6 address corresponding to the China Unicom server to B, so that B can directly access the China Unicom website through the IPv6 protocol stack.

In addition, the present invention provides a system for distinguishing IPv4/IPv6 addresses, as shown in Figure 5, including:

The authoritative DNS10 is configured to receive the destination address information sent by the local DNS20, extract the domain name from the destination address information, and analyze the domain name to obtain an IPv4 address and an IPv6 address corresponding to the domain name, wherein, corresponding to the domain name The IPv6 address is the original IPv6 address or the IPv6 address corresponding to the IPv4 address added by the authoritative DNS10, and the authoritative DNS10 marks the increased IPv6 address corresponding to the IPv4 address, and will correspond to the IPv4 address of the domain name and The IPv6 address is sent to the local DNS20, so that the local DNS can judge whether the server corresponding to the domain name supports the IPv6 protocol stack by whether the IPv6 address corresponding to the domain name has a mark;

Local DNS20, connected to the authoritative DNS10, is used to receive the IPv4 address and IPv6 address corresponding to the domain name, and send the IPv6 address or IPv4 address to the user terminal according to the user type and whether the IPv6 address has a mark , to provide the user terminal with the address corresponding to the domain name accessed by the user.

The embodiment of the present invention provides a system for distinguishing IPv4/IPv6 addresses, by marking the IPv6 addresses added by the authoritative DNS, to identify servers that only support the IPv4 protocol stack (the server only has a native IPv4 address) and simultaneously support the IPv4 protocol stack and the server of the IPv6 protocol stack (the server has a native IPv4 address and an IPv6 address). When a user terminal visits a domain name, according to the type of the user terminal and whether the IPv6 address corresponding to the domain name it visits has a flag, an IPv4 address or an IPv6 address is sent to the user terminal. Therefore, the embodiment of the present invention reasonably provides the address under the domain name for the user according to the user type and the protocol stack supported by the server accessed by the user, so as to avoid the meaningless translation process when the dual-stack user accesses the IPv4 server (i.e., through the NAT64 device) The mutual translation process of IPv4 data packets and IPv6 data packets), so as to not only reduce the access delay of dual-stack users, but also provide sufficient NAT64 translation services for single-stack users, and finally improve the service experience of users.

Optionally, as shown in Figure 6, the authoritative DNS includes:

Address obtaining module 11, for

Querying the domain name address mapping list to obtain the IPv4 address corresponding to the domain name; and

Query the domain name address mapping list, if the original IPv6 address can be queried, the IPv6 address corresponding to the domain name is obtained; if the original IPv6 address cannot be queried, the IPv6 address corresponding to the IPv4 address is added to obtain the corresponding IPv6 address. IPv6 address of the above domain name.

Optionally, as shown in Figure 7, the local DNS includes:

User type judging module 21 is used to judge the user type according to the source address of the user, and the user type includes IPv4 single-stack users, IPv6 single-stack users, and dual-stack users;

The sending module 22 is connected with the user type judging module, and is used to send the IPv4 address or the IPv6 address to the user terminal according to the judgment result of the user type judging module.

Optionally, as shown in Figure 8, the authoritative DNS includes:

A marking module 12, connected to the address acquisition module, configured to set at least one bit of the IPv6 address corresponding to the IPv4 address added by the authoritative DNS as a marking value.

Apparently, the above-mentioned embodiments are only examples for clear description, rather than limiting the implementation. For those of ordinary skill in the art, other changes or changes in different forms can be made on the basis of the above description. It is not necessary and impossible to exhaustively list all the implementation manners here. However, the obvious changes or changes derived therefrom still fall within the scope of protection of the present invention.

Claims (11)

1. A method for distinguishing IPv4/IPv6 addresses, comprising the following steps: Address marking step, the authoritative DNS receives the domain name sent by the local DNS, and obtains the IPv4 address and IPv6 address corresponding to the domain name according to the domain name address mapping list of the authoritative DNS, wherein the IPv6 address corresponding to the domain name is a native IPv6 address or The IPv6 address corresponding to the IPv4 address added by the authoritative DNS, the authoritative DNS marks the added IPv6 address corresponding to the IPv4 address, and sends the IPv4 address and IPv6 address corresponding to the domain name to the local DNS, so that When the local DNS determines that the IPv6 address corresponding to the domain name has a mark, it determines that the server corresponding to the domain name does not support the IPv6 protocol stack; Address sending step, the local DNS receives the IPv4 address and IPv6 address corresponding to the domain name, and sends the IPv4 address or IPv6 address to the user terminal according to the user type and whether the IPv6 address has a mark, so as to provide the corresponding user access for the user terminal The address of the domain name. 2. The method according to claim 1, wherein said obtaining the IPv4 address and the IPv6 address corresponding to said domain name according to the domain name address mapping list comprises: The address acquisition module queries the domain name address mapping list to obtain the IPv4 address corresponding to the domain name; and The address acquisition module queries the domain name address mapping list, if the original IPv6 address can be found, then obtains the IPv6 address corresponding to the domain name; if the original IPv6 address cannot be found, then increases the IPv6 address corresponding to the IPv4 address, An IPv6 address corresponding to the domain name is obtained. 3. The method according to claim 1 or 2, wherein, according to the user type and whether the IPv6 address has a mark, sending the IPv4 address or the IPv6 address to the user terminal comprises: User type judging step, the user type judging module judges the user type according to the source address of the user, and the user type includes IPv4 single-stack users, IPv6 single-stack users and dual-stack users; In the sending step, the sending module sends the IPv4 address or IPv6 address to the user terminal according to the judgment result of the user type judging module. 4. The method according to claim 3, wherein when the user type judging module judges that the user type is a dual-stack user, the sending step specifically includes: If the IPv6 address corresponding to the domain name has a mark, sending the IPv4 address corresponding to the domain name to the user terminal; If the IPv6 address corresponding to the domain name does not have a flag, sending the IPv6 address corresponding to the domain name to the user terminal. 5. The method according to claim 2, wherein the authoritative DNS marking the increased IPv6 address corresponding to the IPv4 address specifically comprises: Setting at least one bit of the IPv6 address corresponding to the IPv4 address added by the authoritative DNS as a flag value. 6. The method according to claim 3, wherein the specific methods adopted in the user type judgment step include: By pre-storing the IP address range of the dual-stack users, judging the user type; and By interacting with the access authentication device, the user type is judged according to the source IPv6 address of the user making the IPv6 resolution request. 7. The method according to claim 6, wherein the access authentication device comprises a broadband remote access server BRAS and a remote user dial-up authentication system RADIUS. 8. A system for distinguishing IPv4/IPv6 addresses, comprising: The authoritative DNS is used to receive the domain name sent by the local DNS, and obtain the IPv4 address and IPv6 address corresponding to the domain name according to the domain name address mapping list of the authoritative DNS, wherein the IPv6 address corresponding to the domain name is a native IPv6 address or an authoritative DNS address. The IPv6 address corresponding to the IPv4 address added by the DNS, the authoritative DNS marks the added IPv6 address corresponding to the IPv4 address, and sends the IPv4 address and IPv6 address corresponding to the domain name to the local DNS, so that the local When DNS determines that the IPv6 address corresponding to the domain name has a mark, it determines that the server corresponding to the domain name does not support the IPv6 protocol stack; The local DNS is connected to the authoritative DNS, and is used to receive the IPv4 address and IPv6 address corresponding to the domain name, and send the IPv6 address or IPv4 address to the user terminal according to the user type and whether the IPv6 address has a mark, so as to The user terminal provides an address corresponding to the domain name accessed by the user. 9. The system according to claim 8, wherein the authoritative DNS comprises: Address acquisition module for Querying the domain name address mapping list to obtain the IPv4 address corresponding to the domain name; and Query the domain name address mapping list, if the original IPv6 address can be queried, the IPv6 address corresponding to the domain name is obtained; if the original IPv6 address cannot be queried, the IPv6 address corresponding to the IPv4 address is added to obtain the corresponding IPv6 address. IPv6 address of the above domain name. 10. The system according to claim 8 or 9, wherein the local DNS comprises: User type judging module, for judging the user type according to the source address of the user, the user type includes IPv4 single-stack users, IPv6 single-stack users and dual-stack users; The sending module is connected with the user type judging module, and is used to send the IPv4 address or IPv6 address to the user terminal according to the judgment result of the user type judging module. 11. The system according to claim 9, wherein the authoritative DNS comprises: A marking module, connected to the address acquisition module, configured to set at least one bit of the IPv6 address corresponding to the IPv4 address added by the authoritative DNS as a marking value.