Enhancing CDN Access Speed with ECS

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AdGuard Private supports the ECS feature, providing more precise resolution to optimize your network experience.

Setup method: Setup method

What is ECS (Extended Client Subnet)?

ECS (Extended Client Subnet) is a DNS protocol extension that allows the DNS resolver (such as your AdGuard Private server) to pass part of the client’s IP address information to the authoritative DNS server. This enables the authoritative server to provide more accurate DNS responses based on the client’s network location.

How ECS Works

  1. Traditional DNS Query: Without ECS, the DNS resolver only sends its own IP address to the authoritative DNS server. This means the authoritative server can only make resolution decisions based on the location of the resolver (usually a data center), which may lead to suboptimal results.

  2. DNS Query with ECS Enabled: When ECS is enabled, the DNS resolver includes a part of the client’s IP address (subnet) in the DNS query. For example, if the client’s IP address is 203.0.113.45, the resolver might send 203.0.113.0/24 as ECS information.

  3. Response from the Authoritative Server: Upon receiving a query with ECS information, the authoritative DNS server can use this information to select the most suitable IP address for the client. This typically means choosing a server geographically closest to the client.

Advantages of ECS

  • Faster Response Times: By directing the client to the nearest server, ECS can reduce latency and improve application response times.
  • Improved User Experience: Faster response times can lead to a smoother and more enjoyable online experience.
  • More Efficient CDN Usage: Content Delivery Networks (CDNs) can use ECS to direct users to the optimal content server, thereby increasing efficiency and reducing costs.
  • Bypassing Local Resolver Limitations: Some local network operators’ DNS servers may have issues, such as incorrect resolution or domain hijacking. Using ECS can bypass these limitations and obtain more accurate resolution results.

Why Use ECS in AdGuard Private?

AdGuard Private, as a private DNS server, can be configured to use upstream DNS servers for domain resolution. When ECS is enabled, AdGuard Private can pass your client subnet information to the upstream server, thereby obtaining more accurate resolution results.