Product Introduction

Domain Resolution Overview

After registering a domain name, you only have the right to use the domain name but cannot directly access your website or use it as an email suffix for sending and receiving emails. "Domain resolution" is a necessary step to access a website using the domain name. People remember domain names, but machines recognize only IP addresses. The conversion between domain names and IP addresses is called domain resolution, and this process is carried out automatically by specialized domain resolution servers. Domain Name System (DNS) resolution is the service that converts domain names (e.g., www.dns.io) into machine-readable IP addresses (e.g., 123.123.123.123).

DNS Resolution Introduction

DNS.IO is a leading DNS service provider in China with 12 years of experience in DNS resolution services.

Product Advantages

• Multiple Nodes: Global leading DNS cluster technology with over 30 domestic cloud cluster nodes and over 20 international cloud cluster nodes, providing professional resolution services.

• Multiple Lines: Real-time updates for domain resolution, supporting detailed line classifications such as mobile, Unicom, and Telecom, and allowing settings for international, domestic, or custom lines.

• Speed: Next-generation high-performance DNS server program provides stable resolution services with speeds exceeding mainstream resolutions by hundreds of times.

• Security: Comprehensive protection system with multiple patented protection algorithms and over 10 TB+ bandwidth reserves, strong high-defense capabilities to easily withstand large-scale attacks.

DNS.IO provides each user with a dedicated DNS, offering higher recognition and security, and eliminating concerns about domain name malicious use by others.

Product Features

• Unlimited Domain Management: Supports comprehensive domain resolution management, allowing unlimited addition of domain resolution records.

• Record Type Description:

  • A Record: Points a domain to an IP address (external network address).
  • AAAA Record: Points a domain to an IPv6 address.
  • CNAME Record: Points a domain to another domain, which then provides the IP address.
  • MX Record: Needed for email setup to receive and send emails based on the recipient's address suffix (domain name).
  • NS Record: Required if you need to delegate subdomains to other DNS service providers.
  • SRV Record: Used to indicate that a server is using a specific service, commonly found in Microsoft system directory management.
  • TXT Record: Used for domain identification and description, mostly for SPF records (anti-spam).
  • CAA Record: Required to authorize specific CA authorities to issue SSL certificates for your domain to prevent incorrect certificate issuance.
  • URL Record: Points a domain to another existing site.

• Intelligent Resolution: Supports smart return of resolution results based on the geographic location of access users.

• Record Types Supported: A, AAAA, MX, CAA, CNAME, HTTPS, TXT, NS, SRV, SVCB, implicit URL, explicit URL.

• IPv4 & IPv6 Dual Stack: Fully supports IPv6 server nodes, allowing free choice between IPv4 and IPv6. IPv4 & IPv6 dual-stack support uses the same set of DNS addresses for both IPv4 and IPv6 DNS servers, greatly reducing maintenance difficulty and improving management efficiency.

• Security Protection: Enhanced DNS resolution security protection provides no less than 10 million QPS defense capability. Comprehensive security protection provides no less than 100 million QPS defense capability, ensuring DNS resolution quality and stability.

• Batch Operations: Batch management of resolution records, including batch export, import, and modification of records.

• Real-Time Effectiveness: Changes to resolution records take effect in real time and synchronize to authoritative DNS servers within seconds.

Application Scenarios

• Website Construction: Use A or AAAA records to point the domain name to the website server's public IP address, allowing users to access the website directly through the domain name instead of using difficult-to-remember IP addresses.

• Email: Use MX records to point to the email server, allowing the email server to receive and send emails based on the recipient's address suffix (domain name).

• Load Balancing: When multiple servers handle the same business, add multiple records of the same host, line, and record type pointing to different servers to balance and distribute traffic across multiple servers, achieving high performance, high availability, and high scalability.

• Intelligent Resolution: Configure smart resolution lines to return resolution results based on users' different geographic locations and carriers to accelerate access and improve user experience.

• CNAME Forwarding: Use CNAME records to map one domain to another, which then provides the IP address. For example, map your business domain to a CDN provider's domain to receive IP addresses from nearby nodes provided by the CDN provider.

• Security Protection: If your domain resolution is frequently attacked, causing business interruptions, you can migrate the domain to DNS.IO to avoid interruptions due to attacks. DNS resolution by DNS.IO provides no less than 100 million QPS defense capability (requires purchase) to ensure DNS resolution quality and stability.

Basic Concepts

DNS Resolution Query Process

Typically, when a user types a website domain into a browser and views the webpage, the domain resolution process involves the following four DNS servers:

• Local DNS Server (DNS Resolver or Local DNS): Generally provided by network operators or other DNS service providers like DNSPod’s public resolution service.

• Authoritative DNS Server: The DNS server set at the domain registrar for specific domain names (e.g., “dnspod.cn”), managing the domain's own resolution records (adding, deleting, modifying, etc.). Authoritative DNS servers only resolve domains they manage and refuse access to non-managed domains.

• Top-Level DNS Server (TLD Nameserver): Maintains information for all domain names with shared generic domain extensions, such as the .com top-level DNS server containing information for all websites ending in “.com”.

• Root DNS Server: When the local DNS server cannot find the resolution result, it first queries the root DNS server, which directs it to the appropriate top-level DNS server based on the domain extension (e.g., .com, .xyz, .cn).

Query Path:

Local DNS Server -> Root DNS Server -> Top-Level DNS Server -> Authoritative DNS Server -> Local DNS Server

(Note: The above path only occurs if DNS is not cached; if cached, the IP address is returned directly.)

For example, when you enter example.com in your browser, the following process occurs:

1. The local DNS server first queries the root DNS server for the address of the top-level DNS server for example.com’s .com domain.

2. After obtaining the top-level DNS server’s address, it queries the top-level DNS server for the authoritative DNS server’s address.

3. Since the example.com domain resolution is managed on this platform, the authoritative DNS server for the platform is obtained, and the local DNS server queries it for the website server’s address.

4. Once the website server address is obtained, the browser sends a request, and the website responds with the webpage content.

DNS Resolution and Domain Registration Relationship

A domain must be registered and paid for at a domain registrar before it can be used. The domain registrar and DNS service provider may differ; the DNS servers set at the registrar will determine who provides DNS resolution services (resolver).