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FAQ about Alibaba Cloud Public DNS

Last Updated: Apr 16, 2021

This topic provides answers to frequently asked questions about Alibaba Cloud Public DNS.

Q1: Which HTTP protocol versions does Public DNS support?

A: Public DNS supports HTTP/1.1 and HTTP/2. 0

Q2: Does the JSON API for DNS over HTTPS (DoH) of Public DNS support Chinese domain names?

A: No, Chinese domain names cannot be transmitted by using the name parameter of the JSON API for DoH. Clients must use punycode to encode Chinese domain names.

Q3: If DNS over TLS (DoT) is enabled for Public DNS, can an IP address be used as the host in a URI?

A: Only IPv4 addresses can be used as the host in a URI. IPv6 addresses cannot pass certificate verification.

Q4: How do I disable Public DNS in the Alibaba Cloud DNS console?

A: If you are using Public DNS Free Edition, you can replace the IP address of the DNS server on your terminal with another IP address to disable the service.

If you are using Public DNS Commercial Edition that is activated on the Public DNS page of the Alibaba Cloud DNS console, disable the service based on the following rules:

- If you activate Public DNS Commercial Edition in public preview, perform no operations in 15 days after the public preview period ends. Then, the service is automatically disabled.

- If you activate Public DNS Commercial Edition after the public preview ends, you can disable the service on the Billing Data tab of the Public DNS page in the Alibaba Cloud DNS console.

Q5: Does Public DNS support DNS Security Extensions (DNSSEC)?

A: No, DNSSEC is not enabled on Public DNS.

Q6: Can I use Public DNS outside mainland China?

A: Public DNS can be accessed by using anycast IP addresses worldwide. This allows you to access the nearest service clusters anywhere in the world.

Q7: Does Public DNS support Anti-DDoS?

A: Yes, the Anti-DDoS feature is provided for all users.

Q8: What do I need to take note of when I call the JSON API for DoH of Public DNS in cross-origin resource sharing (CORS) mode?

A: 1. Set credentials to same-origin, which is the default value. 2. Do not pass custom headers in request headers.

Sample code:

// You can leave the credentials and headers parameters empty to use the default values.
fetch('http://dns.alidns.com/resolve?uid=9999&type=28&name=www.taobao.com', {
  credentials: 'same-origin',
  headers: {}
});

Q9: When does the public preview period of Public DNS Commercial Edition end and what happens then?

A: For more information, see Notice of commercial release.