In today's digital landscape, speed and reliability are paramount. Content Delivery Networks (CDNs) like Akamai play a crucial role in delivering content efficiently by caching it closer to the end user. However, optimizing CDN performance isn't as straightforward as it seems, particularly when it comes to DNS resolution. A key feature that can significantly improve CDN performance is the use of ECS (EDNS Client Subnet). This article explores how ECS works, why Cloudflare's 1.1.1.1 DNS resolver doesn't support it, and how Akamai leverages ECS to ensure content is served from the nearest cache to the request node. Additionally, we'll discuss how you can use Quad9's DNS service (9.9.9.11) to benefit from full ECS support.
What is ECS (EDNS Client Subnet)?
ECS is an extension to the DNS protocol that allows a DNS resolver to include a portion of the client’s IP address (the subnet) in the query sent to a DNS server. This allows the authoritative DNS server, such as those used by CDNs like Akamai, to determine the geographic location of the request more accurately. As a result, the CDN can direct the request to the nearest cache, reducing latency and improving load times.
Why Cloudflare's 1.1.1.1 Doesn't Support ECS
Cloudflare’s 1.1.1.1 DNS resolver is known for its strong emphasis on privacy. ECS, by design, shares part of the user's IP address with the DNS server, which could potentially reveal geographic information about the user. To align with its commitment to user privacy, Cloudflare has chosen not to support ECS, which can sometimes result in suboptimal CDN performance. Without ECS, the CDN may not be able to accurately determine the closest cache, leading to longer load times for users.
Leveraging Quad9's 9.9.9.11 for Full ECS Support
For users and organizations looking to optimize CDN performance without sacrificing ECS functionality, Quad9's DNS service (specifically 9.9.9.11) is an excellent alternative. Quad9 is a public DNS resolver that not only supports ECS but also provides robust security features by blocking access to known malicious domains.
By using Quad9’s 9.9.9.11 DNS resolver, you can ensure that the ECS information is passed along to the CDN’s authoritative DNS servers, like those used by Akamai. This enables the CDN to make more accurate decisions about which cache should serve the content, ensuring that users receive data from the nearest possible location.
For Windows:
Open the Control Panel and navigate to "Network and Sharing Center."
Click on your active network connection and select "Properties."
Select "Internet Protocol Version 4 (TCP/IPv4)" and click "Properties."
Under "Use the following DNS server addresses," enter 9.9.9.11 as the Preferred DNS server.
Click "OK" to save the changes.
For macOS:
Open "System Preferences" and click on "Network."
Select your active network connection and click "Advanced."
Go to the "DNS" tab and click the "+" button to add a new DNS server.
Enter 9.9.9.11 and click "OK," then "Apply."
For Linux:
Open the terminal and use a text editor to modify the /etc/resolv.conf file.
Add the line nameserver 9.9.9.11 to the file.
Save the file and restart your network service or reboot the system.
For Routers:
Access your router’s web interface and locate the DNS settings (usually under WAN or DHCP settings).
Enter 9.9.9.11 as the primary DNS server.
Save the changes and reboot the router if necessary.
Wrap
Using ECS with CDNs like Akamai can significantly enhance the performance of your content delivery by ensuring that requests are served from the nearest cache. While privacy-focused DNS resolvers like Cloudflare’s 1.1.1.1 opt out of ECS to protect user information, alternatives like Quad9’s 9.9.9.11 offer full ECS support. By configuring your devices or network to use 9.9.9.11 (secondary 149.112.112.11), you can strike a balance between performance and security, ensuring that your users experience faster load times and more efficient content delivery.
Another alternative to use as is OpenDNS, 208.67.222.222 which also has ECS support.
