CN102148882B - Method and system for dynamic domain name resolution after deploying NAT - Google Patents

Abstract

The invention provides a dynamic domain name analytic method and system after deployment of NAT (Network Address Translation). The dynamic domain name analytic method comprises the steps: DDNS (Dynamic Domain Name System) subscriber equipment sends a network access request to access equipment of an operator; the access equipment of the operator forwards the network access request to NAT equipmentso as to obtain a public network IP address and a private network IP address from the NAT equipment for DDNS subscriber equipment allocation, and sends the public network IP address and the domain name address of the DDNS subscriber equipment to a DDNS server; the DDNS server correlatively saves the received domain name address and the public network IP address; and when receiving a domain name analytic request from guest user equipment, the DDNS server performs domain name analysis according to the correlatively saved public network IP address and the domain name address. The invention realizes the dynamic domain name analysis under the condition of deployment of NAT by a telecom operator.

Description

Method and system for dynamic domain name resolution after deploying NAT

technical field

The invention relates to a dynamic domain name resolution method and system after deploying Network Address Translation (NAT for short), and belongs to the technical field of domain name resolution.

Background technique

Dynamic Domain Name System (Dynamic Domain Name System, DDNS for short) is a service that can resolve fixed Internet domain names and dynamic IP addresses in real time. Compared with the traditional static DNS, it can resolve a fixed domain name to a dynamic IP address. Whether it changes, it can ensure that other users can access the user's computer through a fixed domain name.

With the rapid development of the Internet, IP addresses have gradually become a scarce resource. For this reason, telecom operators will likely deploy NAT solutions. NAT is a method of converting private (reserved) addresses into legal public IP addresses. Conversion technology, which is widely used in various types of Internet access methods and various types of networks, solves the problem of insufficient 1P addresses to a certain extent, and can effectively avoid attacks from outside the network, hide and protect Computers inside the network.

However, there are at least the following problems in the prior art:

After deploying NAT, users access to the Internet not only dynamically obtain IP addresses, but also obtain private IP addresses. Since the private network IP addresses cannot be routed globally, traditional DDNS cannot work normally.

Contents of the invention

The present invention provides a method and system for dynamic domain name resolution after NAT is deployed, so as to realize dynamic domain name resolution after NAT is deployed.

One aspect of the present invention provides a dynamic domain name resolution method after NAT is deployed, including:

The DDNS user equipment sends a network access request to the operator's access equipment;

The operator access device forwards the network access request to the NAT device, obtains the public network IP address and the private network IP address allocated for the DDNS user equipment from the NAT device, and combines the public network IP address with the The domain name address of the DDNS user equipment is jointly sent to the DDNS server;

The DDNS server associates and saves the received domain name address with the public network IP address;

When the DDNS server receives the domain name resolution request from the visiting user equipment, it performs domain name resolution according to the associated stored public network IP address and domain name address.

Another aspect of the present invention provides a dynamic domain name resolution system, which includes DDNS user equipment, operator access equipment, NAT equipment, and a DDNS server. The DDNS user equipment is located in a private network, and the NAT equipment and DDNS server are located in a public network. In the network, the operator access device is connected to the private network and the public network, wherein:

The DDNS user equipment is used to send a network access request to the operator access equipment;

The operator access equipment includes:

A forwarding module, configured to forward the network access request from the DDNS user equipment to the NAT device;

An acquisition module, configured to obtain a public IP address and a private IP address assigned to the DDNS user equipment from the NAT device, and send the public IP address and the domain name address of the DDNS user equipment to the DDNS server;

The NAT device is used to allocate a public network IP address and a private network IP address for the DDNS user equipment according to the network access request sent by the DDNS user equipment;

The DDNS server includes:

An associating module, configured to associate and store the received domain name address with the public network IP address;

The parsing module is used for performing domain name parsing according to the public IP address and domain name address associated and saved by the association module when receiving a domain name resolution request from a visiting user device from the public network.

The present invention realizes the dynamic domain name analysis function by using the operator's access equipment instead of the DDNS user equipment, thereby realizing the dynamic domain name analysis under the condition that the telecommunication operator deploys NAT.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

Fig. 1 is the flow chart of the embodiment of the dynamic domain name resolution method after deploying NAT described in the present invention;

Fig. 2 is the structural representation of the embodiment of dynamic domain name resolution system of the present invention;

FIG. 3 is a schematic diagram of the internal structure of the operator access device 20 in the system shown in FIG. 2;

FIG. 4 is a schematic diagram of the internal structure of the DDNS server 40 in the system shown in FIG. 2 .

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments It is a part of embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

Fig. 1 is the flow chart of the embodiment of the dynamic domain name resolution method after deploying NAT described in the present invention, as shown in the figure, this method comprises the following steps:

Step 110, the DDNS user equipment sends a network access request to the operator's access equipment.

Wherein, the DDNS user device refers to a device used by a user who wishes to provide dynamic domain name resolution service through a DDNS server, such as a server of a website. Specifically, the DDNS user equipment can connect to the operator through an Ethernet-based point-to-point protocol (Point-to-Point Protocol over Ethernet, referred to as: PPPoE) or an Ethernet-based Internet protocol (Internet Protocol over Ethernet, referred to as: IPoE). The ingress device sends a network access request.

Step 120, the operator's access device authenticates the DDNS user device according to the user name and password carried in the network access request, and then executes step 130 after the authentication is passed.

Wherein, the operator access device may be a broadband remote access server (Broadband Remote Access Server, BRAS for short), which is used to provide remote broadband access services. If the authentication fails, the entire process is ended; the user name and password are obtained when the user applies for a service from the operator.

It should be noted here that if the operator's access device can determine the legitimacy of the DDNS user equipment in other ways, this step can be omitted.

Step 130, the operator access device forwards the network access request to the NAT device, obtains the public network IP address and the private network IP address assigned to the DDNS user equipment from the NAT device, and transfers the public network IP address to the NAT device. The IP address and the domain name address of the DDNS user equipment are jointly sent to the DDNS server.

Specifically, the process for the operator access device to obtain the public network IP address and the private network IP address includes: the operator access device may first forward the network access request to the NAT device, and then Then, the NAT device allocates a public network IP address and a private network IP address for the DDNS user equipment, and returns the allocated public network IP address and private network IP address to the operator access device.

Wherein, the NAT device refers to a device with NAT function; the distribution of the public IP address and the private IP address refers to that the public IP address and the private IP address allocated for the same DDNS user equipment are not fixed Yes, when the DDNS user equipment is disconnected and sends a network access request again, the NAT device may assign different public IP addresses and private IP addresses to it; the domain name address of the DDNS user equipment is the Submitted by the operator when applying for business.

Step 140, the DDNS server associates and saves the received domain name address and the public network IP address.

Step 150, when the DDNS server receives a domain name resolution request from the visiting user equipment, perform domain name resolution according to the associated stored public network IP address and domain name address.

Wherein, the visiting user equipment refers to a user terminal that wants to access the DDNS user equipment. Specifically, the DDNS server can search for the corresponding public IP address from the associated saved public IP address and domain name address according to the domain name address carried in the domain name resolution request and return it to the visiting user equipment, so as to Realize domain name resolution.

Thereafter, the visiting user equipment can communicate with the DDNS user equipment through the public network IP, which may specifically include the following steps:

Step 160, the visiting user equipment sends a communication data packet to the operator access equipment with the received public network IP address as the destination address.

Step 170, the operator access device searches for a corresponding private network IP address according to the public network IP address, and sends the communication data packet to the corresponding DDNS user equipment according to the private network IP address.

Specifically, the operator access device may look up the private network IP address corresponding to the public network IP address according to the address mapping table of the public network IP address and the private network IP address stored in the NAT device, and at this time The address mapping table is generated and stored in the NAT device when the NAT device allocates a public network IP address and a private network IP address for the DDNS user equipment in step 130;

Alternatively, the operator access device may also search for the private network IP address corresponding to the public network IP address according to the address mapping table between the public network IP address and the private network IP address stored by the operator access device itself, where The current address mapping table is generated according to the public network IP address and private network IP address obtained by the operator access device from the NAT device in step 130, and is stored in the operator access device.

The method described in this embodiment implements the dynamic domain name resolution function by using the operator's access device instead of the DDNS user device, thereby realizing the dynamic domain name resolution under the condition that the telecom operator deploys NAT.

Fig. 2 is the structure diagram of the embodiment of dynamic domain name resolution system of the present invention, as shown in the figure, this system comprises: DDNS user equipment 10, operator's access equipment 20, NAT equipment 30 and DDNS server 40, described DDNS user The device 10 is located in the private network, the NAT device 30 and the DDNS server 40 are located in the public network, and the operator access device 20 is connected to the private network and the public network, and its working principle is as follows:

The DDNS user equipment 10 sends the network access request to the operator access equipment 20, wherein the DDNS user equipment 10 refers to equipment used by users who wish to provide dynamic domain name resolution services through the DDNS server 40, For example, a website server, etc. Specifically, the DDNS user equipment 10 may send a network access request to the operator access device 20 in a PPPoE-based or IPoE-based manner.

Thereafter, as shown in FIG. 3 , the operator access device 20 authenticates the DDNS user equipment 10 through the authentication module 23 according to the username and password carried in the network access request, and then passes the authentication through forwarding The module 21 forwards the network access request from the DDNS user equipment 10 to the NAT device 30, and the NAT device 30 allocates a public address for the DDNS user equipment according to the network access request sent by the DDNS user equipment 10. network IP address and private network IP address. Wherein, the operator access device 20 may be, for example, a BRAS. It should be noted here that if the operator access device 20 can determine the legitimacy of the DDNS user equipment 10 in other ways, the authentication module 23 may be omitted.

Thereafter, the operator access device 20 obtains the public network IP address and the private network IP address allocated for the DDNS user equipment 10 from the NAT device 30 through the obtaining module 22, and combines the public network IP address with the DDNS The domain name address of the user equipment 10 is jointly sent to the DDNS server 40

Thereafter, as shown in Figure 4, the DDNS server 40 associates the received domain name address with the public network IP address through the association module 41 and saves it; When requesting, the domain name resolution is performed by the resolution module 42 according to the public network IP address and the domain name address associated and saved by the association module. Wherein, the visiting user equipment refers to a user terminal that wants to access the DDNS user equipment. Specifically, the parsing module 42 may search for the corresponding public IP address from the associated saved public IP address and domain name address according to the domain name address carried in the domain name resolution request and return it to the visiting user equipment, for domain name resolution.

Thereafter, the visiting user equipment can communicate with the DDNS user equipment 10 through the public network IP, specifically, the visiting user equipment first uses the received public network IP address as the destination address to connect to the operator The access device 20 sends a communication data packet; when the operator access device 20 receives the communication data packet sent by the visiting user equipment with the public network IP address as the destination address, the search module 24 will The network IP address searches for the corresponding private network IP address, and then the communication module 25 sends the communication data packet to the corresponding DDNS user equipment according to the private network IP address found by the search module 24. For a specific search process, reference may be made to relevant content in the implementation example of the foregoing method.

The system in this embodiment implements the dynamic domain name resolution function by using the operator's access device instead of the DDNS user device, thereby realizing the dynamic domain name resolution under the condition that the telecom operator deploys NAT.

The following example illustrates the signaling process implemented by the system described in this embodiment, as shown in Figure 2, including the following process:

(1) The DDNS user equipment sends a network access request to the operator's access equipment through PPPoE or IPoE;

(2) The operator access device may first send the network access request to the NAT device;

(3) The NAT device allocates a public network IP address and a private network IP address for the DDNS user equipment, and returns the distributed public network IP address and private network IP address to the operator access device;

(4) The operator's access device sends the public network IP address and the domain name address of the DDNS user equipment to the DDNS server, and the DDNS server associates and saves the received domain name address and the public network IP address ;

(5) The visiting user equipment sends a domain name resolution request to the DDNS server;

(6) DDNS server carries out domain name resolution according to the described public network IP address and domain name address that have associated preservation, and returns corresponding public network IP address to described visiting user equipment;

(7) The visiting user equipment sends a communication data packet to the operator access equipment with the received public network IP address as the destination address;

(8) The operator's access device requests the NAT device to inquire about the private IP address corresponding to the public network IP address;

(9) The NAT device returns the private IP address found;

(10) The operator access device sends the communication data packet to the corresponding DDNS user equipment according to the private network IP address.

It should be noted here that if the operator access device supports maintaining an address mapping table between a local public network IP address and a private network IP address, the operator access device can directly query the local address mapping table, Therefore, the above steps (8) and (9) can be omitted.

Those of ordinary skill in the art can understand that all or part of the steps for realizing the above-mentioned method embodiments can be completed by hardware related to program instructions, and the aforementioned program can be stored in a computer-readable storage medium. When the program is executed, the It includes the steps of the above method embodiments; and the aforementioned storage medium includes: ROM, RAM, magnetic disk or optical disk and other various media that can store program codes.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still be Modifications are made to the technical solutions described in the foregoing embodiments, or equivalent replacements are made to some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims (9)

1. a dynamic domain name resolution method after deploying NAT, it is characterized in that comprising: The DDNS user equipment sends a network access request to the operator's access equipment; The operator access device forwards the network access request to the NAT device, obtains the public network IP address and the private network IP address allocated for the DDNS user equipment from the NAT device, and combines the public network IP address with the The domain name address of the DDNS user equipment is jointly sent to the DDNS server; The DDNS server associates and saves the received domain name address with the public network IP address; When the DDNS server receives the domain name resolution request from the visiting user equipment, it performs domain name resolution according to the associated stored public network IP address and domain name address. 2. The method according to claim 1, wherein the DDNS user equipment sending a network access request to the operator access device comprises: the DDNS user equipment sends a network access request to the operator access device through PPPoE or IPoE Network access request. 3. The method according to claim 1, further comprising: before the operator access device forwards the network access request to the NAT device: the operator access device according to the network access request The user name and password carried in the incoming request are used to authenticate the DDNS user equipment. 4. The method according to claim 1, wherein said performing domain name resolution according to the associated stored public network IP address and domain name address comprises: according to the domain name address carried in the domain name resolution request, from the associated saved Find the corresponding public network IP address from the public network IP address and domain name address and return it to the visiting user equipment. 5. The method according to claim 4, further comprising: The visiting user equipment sends a communication data packet to the operator access equipment with the received public network IP address as the destination address; The operator access device searches for a corresponding private network IP address according to the public network IP address, and sends the communication data packet to the corresponding DDNS user equipment according to the private network IP address. 6. The method according to claim 5, wherein searching for the corresponding private network IP address by the operator access device according to the public network IP address comprises: according to the operator access device or the NAT device Search the private network IP address corresponding to the public network IP address in the address mapping table of the public network IP address and the private network IP address stored in the . 7. A dynamic domain name resolution system, characterized in that it includes DDNS user equipment, operator access equipment, NAT equipment and DDNS server, the DDNS user equipment is located in the private network, and the NAT equipment and the DDNS server are located in the public network , the operator access device connects the private network and the public network, wherein: The DDNS user equipment is used to send a network access request to the operator access equipment; The operator access equipment includes: A forwarding module, configured to forward the network access request from the DDNS user equipment to the NAT device; An acquisition module, configured to obtain a public IP address and a private IP address assigned to the DDNS user equipment from the NAT device, and send the public IP address together with the domain name address of the DDNS user equipment to the DDNS server; The NAT device is used to allocate a public network IP address and a private network IP address for the DDNS user equipment according to the network access request sent by the DDNS user equipment; The DDNS server includes: An associating module, configured to associate and store the received domain name address with the public network IP address; The parsing module is used for performing domain name parsing according to the public network IP address and domain name address associated and saved by the association module when receiving a domain name resolution request from a visiting user device from the public network. 8. The system according to claim 7, wherein the operator access device further comprises: an authentication module, configured to authenticate the DDNS user equipment according to the username and password carried in the network access request. certified. 9. The system according to claim 7, characterized in that the operator access device further comprises: A search module, configured to search for a corresponding private network IP address according to the public network IP address when receiving a communication packet sent by the visiting user equipment with the public network IP address as the destination address; The communication module is configured to send the communication data packet to the corresponding DDNS user equipment according to the private network IP address found by the search module.

Images