Resolution For a Faster Site - How DNS Affects Page Load Time

Ido Safruti (PerimeterX)
Web Performance, Mission City Ballroom B1
Average rating: ***..
(3.05, 21 ratings)

More than 50% of the Alexa top 1,000 companies use “plain” DNS (internal vanilla service or basic service from their ISP). Why? DNS is often overlooked until it breaks down. Let’s face it, we take fast and reliable DNS resolution for granted, and focus all our efforts on optimizing what happens after a connection to the server is established, but in many cases it spells SPOF.

Even when everything works well, DNS has a significant impact on user experience. An average page uses 15 domains (per, meaning
15 DNS resolutions, with each often taking up to 50 ms, and much more on mobile networks. Additional factors like high latency mobile networks, heavy use of CNAMEs and low-powered home routers make this problem worse.
Implementing a fast and efficient DNS service, and understanding how DNS works on different browsers and operating systems and devices becomes critical for overall web performance.

In this session you can learn:

  • A quick refresher on DNS basics, and tips for doing it right
  • How different operating systems and Browsers handle DNS
  • Best practices of DNS performance and web performance recommendations
  • How CDNs use DNS and how to optimize around it
  • The do-s and don’ts of using DNS for high availability and load-balancing
    to summarize the lessons learned I will walk you through some real world examples, analyzing the good and the bad.

To finish this session I will share analysis and best practices on newer and less discussed protocols like IPv6, DNSSEC and the impact of open resolvers. Even though these are supported by a small portion of the user-base, they may have significant impact on performance of the rest of the user-base and are growing on their own, and calls for additional consideration.

Photo of Ido Safruti

Ido Safruti


Ido Safruti heads a product group in Akamai focusing on web performance and scalability. In his role Ido is an evangelist of performance technologies and innovation in Akamai, and participates in the efforts to draft HTTP/2.0.
Ido joined Akamai through the acquisition of Cotendo where he lead product and market strategy. Prior to Cotendo Ido was CEO and co-founder of CampusTech that focused on placement and commercialization of academic-created technologies, and prior to that Ido was General Manager at Metacafe, when it was one of the largest short video sites in the world, with responsibility for R&D, and IT operations. Earlier roles include R&D Manager, Chief Scientist, and Head of Software at various companies focused on high capacity network software, hardware, and security systems.


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