For people who worry about the plumbing and inner-workings of the internet, this week is really important.

Friday 1 February 2019 is DNS Flag Day, and if you’ve never heard of it don’t assume it shouldn’t be in your calendar.Flag Day marks the evolution of DNS to a new implementation known as EDNS (enhanced domain name system), a faster, more efficient and potentially more secure level of compliance.[#pullquote#]If websites and domain names are not hosted by an EDNS compliant service before the beginning of February they could fall offline.[#endpullquote#]If websites and domain names are not hosted by an EDNS compliant service before the beginning of February they could fall offline.So, pause scrolling for a second and run a quick check.What are the changes?Changes are coming about after DNS service and software providers announced that they would no longer accommodate non-EDNS protocol compliant systems following Flag Day.Major open source resolvers will release updates that will stop accommodating non-standard responses from authoritative DNS servers which do not correctly implement EDNS.[#pullquote#]DNS software providers have already released versions fully compliant with EDNS [#endpullquote#]DNS software providers have already released versions fully compliant with EDNS, so for DNS services running current versions of software there should be little to worry about.Not to be overlooked from 1 February, it is also important that firewalls do not drop DNS packets with EDNS extensions. This would prevent DNS resolution and requires configuration changes before the deadline.Some would say that there has been surprisingly little publicity in the run-up to the long-awaited DNS Flag Day. For the less vigilant (or just busy) administrators, we think a reminder to check all essential services is well worth it.What to do nextFortunately, thanks to the Internet Systems Consortium (ISC) it’s very easy to find out more and check whether your domains are all ready to go, or if you need to make some quick changes this week.The DNS Flag Day website offers a simple way to check your domain for compliance and has plenty of advice for domain or DNS service owners.For more detail and background, the ISC has covered all the bases in their post, DNS Flag Day – will it affect you?