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Intelligent DNS resolution

Last Updated: Aug 27, 2020

Scenarios

Intelligent DNS resolution applies to the following scenarios:

1 . Access business across carrier networks or geographic areas in China: Usually, enterprises host their applications on multiple servers, whose IP addresses are provided by different carriers. A traditional DNS server returns these IP addresses to visitors randomly or based on service loads. The IP address returned to a visitor may be in a different carrier network or geographic area from the visitor. In this case, the visitor experiences high latency or poor network quality. You can configure intelligent DNS resolution to address these issues.

2 . Access business worldwide: If enterprises serve users around the world, they deploy application servers in China and other countries to ensure that users can have quick access to their business. In this scenario, you can use intelligent DNS resolution to route users to the nearest servers. This allows you to improve the performance of your business.

3 . Restrict visitors in a carrier network or geographical area from accessing your business: Some enterprises want to deny access from specific visitors. For example, you want to limit access to your application from specific areas. You can use intelligent DNS resolution to restrict visitors from accessing your business.


Preparations

Access business across carrier networks or geographic areas in China

  • Domain name, for example, dns-example.com. We recommend that you use the Enterprise Standard Edition of Alibaba Cloud DNS.
  • Three IP addresses: 1.1.1.1 (China Unicom), 2.2.2.2 (China Mobile), and 3.3.3.3 (China Telecom).

Access business worldwide

  • Domain name, for example, dns-example.com. We recommend that you use the Enterprise Standard Edition of Alibaba Cloud DNS.
  • Two IP addresses: 1.1.1.1 (located outside China) and 2.2.2.2 (China Telecom).

Restrict visitors in a carrier network or geographical area from accessing your business

  • Domain name, for example, dns-example.com. We recommend that you use the Enterprise Standard Edition of Alibaba Cloud DNS.
  • IP address: 2.2.2.2 (China Telecom).


Configuration

Access business across carrier networks or geographic areas in China


You can configure DNS records so that Alibaba Cloud DNS can return IP addresses to visitors based on the carrier networks they come from.

  • If the local DNS server of a visitor is provided by China Mobile, 2.2.2.2 is returned.
  • If the local DNS server of a visitor is provided by China Telecom, 3.3.3.3 is returned.
  • If the local DNS server of a visitor is provided by another carrier, such as Dr.Peng or China Unicom, 1.1.1.1 is returned.


Procedure

1 . Log on to the DNS console.
2 . On the Domains tab of the Manage DNS page, click your domain name to go to the DNS Settings page.
Click a domain name
3 . On the DNS Settings page, click Add Record. Add three records to map the subdomain test.dns-example.com to the three IP addresses: 1.1.1.1 (China Unicom), 2.2.2.2 (China Mobile), and 3.3.3.3 (China Telecom). Set the ISP Line field of the records to Default, China Mobile, and China Telecom, respectively.
Add Record button
Add Record dialog box
Record list

Access business worldwide


The following results are achieved after the configuration:

  • If the local DNS server of a visitor resides outside China, 1.1.1.1 is returned.
  • If the local DNS server of a visitor resides in China, 2.2.2.2 is returned.


Procedure
Worldwide business access

Restrict visitors in a carrier network or geographical area from accessing your business


You can achieve the following result after the configuration:

  • If the local DNS server of a visitor resides outside China, 127.0.0.1 is returned. This IP address blocks access requests from this visitor.
  • If the local DNS server of a visitor resides in China, 2.2.2.2 is returned.


Procedure

Block access outside China