dns flag day

What is DNS Flag DAY?

A number of DNS software and service providers have announced that they will all cease implementing DNS resolver workarounds to accommodate DNS authoritative systems that don’t follow the EDNS protocol, on or around February 1st 2019.

As a result, domains hosted on servers which do not fully support EDNS may be unreachable or suffer from degraded performance. Read more about the EDNS.

How do I test my own zones?

Exabytes Windows/Linux shared hosting clients who are using Exabytes Network default DNS are safe. For more details, please refer to Exabytes announcement. If you are using load balancers and/or firewalls that are incompletely/incorrectly configured or that are unaware of current DNS protocol standards, please check whether your domain will be affected by this change at https://dnsflagday.net


  1. DNS Flag Day – will it affect you?
  2. 2019 | DNS flag day
  3. National Cyber Coordination and Command Centre (NC4)

If you need further information and clarifications regarding this announcement, please do not hesitate to contact us via helpdesk at https://support.exabytes.com

Examples of test results:

dns-safe flag day test resultYou are safe!
If your test result is similar to this screenshot, good job, you are safe and no worries.


dns problem flag day test resultMinor Problem Detected!
If your test result is similar to this screenshot, take it easy, your website is still loading fine. Do contact our support if you wish to know more.

Notify of
Inline Feedbacks
View all comments