Access IPv4 services from IPv6 clients by using GA

Limits

Only IPv6 clients in the following regions can connect to GA: China (Qingdao), China (Beijing), China (Hangzhou), China (Shanghai), China (Shenzhen), China (Heyuan), China (Guangzhou), China (Chengdu), China (Hong Kong), Singapore (Singapore), US (Virginia), and Germany (Frankfurt). Make sure that the acceleration region that you add belongs to one of the preceding regions.

Scenarios

An enterprise has deployed services in data centers that use IPv4 networks. The enterprise needs to provide services to IPv6 clients due to business development. However, it is complex and time-consuming for the enterprise to reconfigure the current service system to support IPv6 requests. In this scenario, the enterprise can use GA to enable the service system to support IPv6 requests without changing the service system. After GA processes requests from IPv6 clients, the requests are routed to backend IPv4 services. If some enterprises have their services deployed on the cloud, the enterprises can also use GA to enable the services to support requests from IPv6 clients.

The following example describes how to deploy a GA instance to enable IPv4 services to support IPv6 requests. An enterprise in China (Beijing) has deployed the service system in a data center that uses IPv4 networks. The enterprise plans to use GA to provide IPv4 web services to IPv6 clients due to business development.

Procedure

Step 1: Purchase a GA service bundle

You can enter the information about the web service in the GA console. After you enter the information, the system generates a list of recommended services. The list includes a GA instance and a basic bandwidth plan.

1. Log on to the Global Accelerator console.
2. In the upper-right corner of the Instances page, click Purchase Guide.
   Note If this is the first time that you use the GA service, skip this step.

   
3. In the Enter the required information to generate a list of recommended services section, enter the required information and click Generate Service List.

   Parameter	Description
   Acceleration Area	Select the region that requires acceleration. In this example, China (Beijing) is selected.
   Service Region	Select the region where the backend servers are deployed. In this example, China (Beijing) is selected.
   ICP Filing	Specify whether you have applied for an Internet Content Provider (ICP) number for the domain name of the web service. Yes is selected in this example. Note All websites must obtain an ICP number before they are permitted to provide services to users in the Chinese mainland. For more information, see What is an ICP filing?.
   Server Area	Specify whether the backend service is deployed on Alibaba Cloud. In this example, Off Alibaba Cloud is selected.
   Peak Bandwidth Range	Enter the bandwidth required during peak hours. Unit: Mbit/s. In this example, 2 is entered.
   Maximum Concurrent Connections	The maximum number of concurrent connections that a GA instance supports. When the number of existing concurrent connections reaches the upper limit, new connection requests are dropped. In this example, 5 Thousand is selected.

4. In the Recommended Service List section, click Generate Service List after you confirm the information.
   
5. On the buy page, set the following parameters and click Buy Now to complete the payment.

   Parameter	Description
   Term	Select the subscription duration.
   Specification	Select a specification for the GA instance. In this example, Small I (Specification Unit) is selected.
   Bandwidth Type	Select a bandwidth type for the basic bandwidth plan. In this example, Enhanced is selected.
   Peak Bandwidth	Select the bandwidth limit of the basic bandwidth plan. In this example, 2 Mbit/s is selected.

Step 2: Add an acceleration area

After you purchase a GA instance, you can add an acceleration area, specify the region where users are located, and then allocate bandwidth resources to the region.

1. On the Instances page, find the GA instance and click its ID.
2. Click the Acceleration Areas tab and then click Add Region on the China North tab.
3. In the Add Acceleration Area dialog box, set the following parameters and click OK.

   Parameter	Description
   Regions	Select the region where the users that require the acceleration service are located. In this example, China (Beijing) is selected.
   Bandwidth	Allocate bandwidth to the region. In this example, 2 Mbit/s of bandwidth is allocated.
   Internet Protocol	Select the Internet protocol that is used by the users to connect to GA. In this example, IPv6 is selected.

   After you add the region, the system allocates an accelerated IPv6 address to the region. The IPv6 address is used to accelerate user access.

Step 3: Add a listener and an endpoint group

A listener checks for connection requests and then distributes the requests to backend servers based on the specified protocol and ports. Each listener is associated with an endpoint group. You can associate an endpoint group with a listener by specifying the region to which you want to distribute network traffic. After you associate an endpoint group with a listener, traffic is distributed to the optimal endpoint in the associated endpoint group.

1. On the instance details page, click the Listeners tab and then click Add Listener.
2. On the Configure Listener & Protocol wizard page, specify the following listener information and click Next.
   

   Parameter	Description
   Listener Name	Enter a name for the listener. The name must be 2 to 128 characters in length, and can contain letters, digits, underscores (_), and hyphens (-). The name must start with a letter.
   Protocol	Select the protocol of the listener. In this example, TCP is selected.
   Port Number	Specify a listener port. The port is used to receive and forward requests to endpoints. Valid values: 1 to 65499. In this example, the value is set to 80.
   Client Affinity	Specify whether to enable client affinity. If client affinity is enabled, requests from the same client are forwarded to the same endpoint when the client connects to a stateful application. In this example, Source IP Address is selected.

3. On the Configure Endpoint Group wizard page, specify the following endpoint group information and click Next.

   Parameter	Description
   Endpoint Group Name	Enter a name for the endpoint group. The name must be 2 to 128 characters in length, and can contain letters, digits, underscores (_), and hyphens (-). The name must start with a letter.
   Region	Select the region where you want to create the endpoint group. The servers that the IPv6 clients want to access must be deployed in the specified region. In this example, China (Beijing) is selected.
   Backend Service	Specify whether the backend service is deployed on Alibaba Cloud. In this example, Off Alibaba Cloud is selected.
   Preserve Client IP	Specify whether to preserve client IP addresses. After you enable this feature, backend servers can retrieve client IP addresses. In this example, client IP address preservation is disabled.
   Endpoint	Endpoints are destinations of client requests. To add an endpoint, specify the following parameters: Backend Service Type: In this example, Custom IP Address is selected. Backend Service: Enter the public IP address of the IPv4 web service. Weight: Enter the weight of the endpoint. Valid values: 0 to 255. GA distributes network traffic to endpoints based on their weights. Notice If the weight of an endpoint is set to 0, GA stops distributing network traffic to the endpoint. Proceed with caution.

4. On the Confirm wizard page, confirm the configurations of the listener and endpoint, and then click Submit.

Step 4: Configure DNS settings

1. Log on to the Alibaba Cloud DNS console.
2. On the Manage DNS page, find the domain name and click Configure in the Actions column to go to the DNS Settings page.
3. Click Add Record, set the following parameters, and then click Confirm.
   • Add an AAAA record

     Parameter	Description
     Type	Select AAAA. The AAAA record is used to map the domain name for the IPv4 service to the IPv6 address allocated by GA.
     Host	Enter the prefix of the domain name that you want to accelerate. If the domain name is www.aliyun.com, set the prefix to www. If the domain name is aliyun.com, set the prefix to @. If the domain name is *.aliyun.com, set the prefix to *. If the domain name is mail.aliyun.com, set the prefix to mail.
     ISP Line	Select Default from the drop-down list.
     Value	Enter the accelerated IPv6 address that is allocated by GA.
     TTL	Select 10 minute(s) from the drop-down list. The time-to-live (TTL) period of the DNS record on the DNS server.

   • Add a CNAME record

     Parameter	Description
     Type	Select CNAME from the drop-down list. The CNAME record is used to map the domain name for the IPv4 service to the CNAME allocated by GA.
     Host	Enter the prefix of the domain name that you want to accelerate. If the domain name is www.aliyun.com, set the prefix to www. If the domain name is aliyun.com, set the prefix to @. If the domain name is *.aliyun.com, set the prefix to *. If the domain name is mail.aliyun.com, set the prefix to mail.
     ISP Line	Select Default from the drop-down list.
     Value	Enter the CNAME that is allocated by GA. You can find the CNAME on the Instances page.
     TTL	Select 10 minute(s) from the drop-down list. The TTL period of the DNS record on the DNS server.

     Note

     • New CNAME records immediately take effect. If you modify the CNAME record, the record takes effect within 72 hours after it is modified.
     • After you add a CNAME record, it requires about 10 minutes for the system to update the status in the console. The message "You must add the CNAME record" may appear on the Domain Names page.

Step 5: Verify the acceleration performance

1. Open the command prompt on an IPv6 client in the acceleration region. In this example, the IPv6 client is deployed in the China (Beijing) region.
2. Run the following command to check whether the IPv6 client can access the IPv4 service:

   curl -6 -g http://[<Accelerated IP address assigned by GA>]

   Note In this example, the test is performed on the CentOS operating system. The command that is used to run the test may vary based on the operating system. For more information, refer to the user guide of the operating system.

   The test result shows that the IPv6 client can access the IPv4 web service by using the accelerated IP address.