What is DNS Flag DAY?

DNS Flag Day is 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. 2020 | 2019 DNS flag day
  3. National Cyber Coordination and Command Centre (NC4)
    DNS Flag Day 2019

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