This topic provides answers to frequently asked questions (FAQ) regarding intelligent DNS resolution.
FAQs
Solutions to inaccurate intelligent DNS resolution
The solutions described in this section are applied to domain names that are resolved by using Alibaba Cloud Domain Name System (DNS). If your domain names are hosted by the DNS servers of other vendors, contact the vendors for specific solutions. If you use domain names that are hosted by the DNS servers of Alibaba Cloud DNS, you can refer to solutions to inaccurate intelligent DNS resolution for further solutions when you encounter inaccurate intelligent DNS resolution.
How is the intelligent DNS resolution feature billed?
The intelligent DNS resolution feature is not separately billed. The fee of this feature is included in the fees you pay when you purchase an edition of Alibaba Cloud DNS. In addition, the supported resolution lines vary based on the edition of Alibaba Cloud DNS. For more information, see Pricing and Edition comparison.
What is the intelligent DNS resolution feature of Alibaba Cloud DNS?
In intelligent DNS resolution, specified IP addresses of website servers are returned to visitors based on the DNS request sources of the visitors. If multiple A records of different request lines are added to a domain name, the system perform DNS resolution based on the geographic location or Internet service providers (ISPs) of the source IP address of DNS requests. Typically, the IP address refers to the egress IP of the local DNS server used by the visitor. If the local DNS server supports the EDNS protocol, the system uses the extended IP information provided (including geographic location and ISPs) to match the preset DNS resolution rules and respond accordingly, returning different IP addresses. This feature supports flexible configuration based on conditions such as ISPs and geographic location.
How does intelligent DNS resolution determine the geographical location of a visitor?
Intelligent DNS resolution determines the geographic location of a visitor based on the outbound IP address of the visitor's local DNS server.
Why am I unable to set regional lines in the Chinese mainland?
You can set regional lines in the Chinese mainland. The regions include East China, North China, Central China, South China, Southwest China, Northwest China, and Northeast China. For more information, see DNS resolution lines. Note that these regional lines are exclusively available with the enterprise edition of Alibaba Cloud DNS.
How do I switch user request traffic to a functioning server by using intelligent DNS resolution when a server fails?
Intelligent DNS resolution does not support the removal of abnormal IP addresses or automatic failover. If you need these features, we recommend that you see What is GTM?
Does intelligent DNS resolution support nearby access if I have two servers hosted by China Mobile and China Unicom?
Yes, intelligent DNS resolution supports nearby access. Intelligent DNS resolution allows China Mobile users to access the server IP address provided by China Mobile and China Unicom users to access the server IP address provided by China Unicom. For more information, see Intelligent DNS resolution.
Can I point a domain name to multiple server IP addresses by using intelligent DNS resolution, and select overlapping geographic locations for resolution lines? If yes, how does Alibaba Cloud DNS respond to DNS requests?
Yes, you can point a domain name to multiple server IP addresses and select overlapping geographic locations for resolution lines. For example, assume that you select Outside mainland China, Asia, and Singapore for resolution lines. If a visitor is in Singapore, Alibaba Cloud DNS returns the IP address specified for the Singapore line. If a visitor is in Asia but not in Singapore, Alibaba Cloud DNS returns the IP address specified for the Asia line. If a visitor is in a continent other than Asia, Alibaba Cloud DNS returns the IP address specified for the line outside the Chinese mainland.