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Dan Fry posted in: Business Developer

DNS or The Domain Name System is one of the foundations of the internet. The odd thing is that most people outside of networking probably don’t realise they’re using it every day.

It was developed over two decades ago to allow computers to communicate with each other. Over the last two decades the face of the tech industry has changed a lot, but DNS systems and compliance hasn’t been updated.

In recent years there has been an industry push towards keeping DNS services running quickly, smoothly and at optimum performance.  The Internet Systems Consortium (ISC) in partnership with  Google, CloudFlare, PowerDNS, Quad9, Facebook and CleanBrowsing have come together to announce Feb the 1st 2019 as DNS Flag Day.

What is DNS?

The Domain Name System (DNS) is the postal system for the internet, every connected device on the internet including Mobile Phones, Laptops and IoT devices all need an IP to communicate – this is known as their IP address, DNS is the system and method in place that can convert a domain name such as and provide the correct IP address allowing your devices to communicate with the correct machine for resources, such as loading webpages or sending Facebook messages. Without DNS we would all be entering a very long string of characters and digits into the browser to visit our favourite sites and the internet would not be the vibrant, custom and huge forum of humanity that it is today.

What’s happening on DNS Flag day?

Any DNS zones that do not comply with the main DNS standard (RFC1034) or the newer standards for Extensions to DNS (EDNS, RFC2671, RFC6891) will be removed for having non-compliant DNS implementations. These changes are being deployed into multiple big public DNS providers along with vendors of DNS software whom will be removing the current workarounds allowing non-standard DNS

Do I need to worry on DNS Flag day?

If you do happen to have a domain name, or you are a DNS Administrator or System Admin you may want to check if there will be any disruption to your websites availability, you can run a simple check on

If you’re an internet user simply browsing the web without your own domain name you don’t need to do anything!

As a DNS admin / software developers what do I do?

The main change is that DNS software from vendors named above will interpret timeouts as a sign of a network or server problem. Starting 1st February 2019 there will be no attempt to disable EDNS in reaction to a DNS query timeout.

This effectively means that all DNS servers which do not respond at all to EDNS queries are going to be treated as dead. It is important to note that EDNS is still not mandatory. If you decide not to support EDNS it is okay as long as your software replies according to EDNS standard section 7. 

Please test your implementations using the ednscomp tool to make sure that you handle EDNS properly.

All Memset provided DNS servers are fully RFC compliant and so If you’re using our services you will be unaffected, however, it’s worth checking your own domains.


This post was written by Dan Fry, Memset Technical Service Engineer.