In October 2016, GOV.UK and various other government services were affected by an incident that took our services offline.

On the GOV.UK blog, I’ve recently published an incident report that talks about the causes and what we are doing to prevent it from happening again.

This post is a report about 2 recent incidents on the GOV.UK website. We’re still working through our incident process, but due to the scale of these issues, we felt it was important to publish our report as soon as possible.

This post covers 2 similar and related incidents:

  • an intermittent outage of the GOV.UK website and related services for around 3 hours on Friday 21 October 2016
  • an intermittent outage of just the GOV.UK website for around 25 minutes on Wednesday 26 October 2016

Both incidents were related to problems with DNS - a mechanism used to convert a website address like ‘www.gov.uk’ to an IP address like ‘151.101.60.144’.

Browsers use DNS to identify the IP address of a website so they can send requests back and forth.