Lightboard Lessons: Be Ready...DNS Flag Day is Coming!

February 1, 2019 is DNS Flag Day. This day could be catastrophic to your website if you don't have the appropriate configurations in place for your DNS servers. In this video, I outline the details of DNS Flag Day and talk about what to do to make sure you are ready for the big transition that is coming. Enjoy!


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Published Jan 25, 2019
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  • Excellent explanation John! One Important thing: If you manage a Normal Cache Resolver DNS inside your company, is not mandatory to update your DNS to send EDNS and only accept EDNS responses. The most sensitive point is to make EDNS-compatible the Authoritative DNS, this issue is very important because starting 1 Feb several DNS resolver vendors will not accept noEDNS Authoritative DNS responses.




  • Hey,


    In case of EDNS tester had scored my domains as "Minor problems detected!" and in my need to postpone my BIG-IP update to due to possible new issues not yet tested, do you think is good workaround to apply the code from here:, plus adding code to fix buffer size "DNS::edns0 sz 512", it covers all is needed for awhile? This way, should I be "compliant"? Is it a good workaround till the BIG-IP version can be updated or need I just to plan upgrade soon I can?


    Thank you in advance.