Control D's Bad Setting Sat Dormant for 25 Days, Then a Fail-Closed Startup Check Turned One Reload Into a Fleet-Wide Outage

Fri, 23 Oct 2026 08:30:00 +0530

Control D’s paid DNS stopped answering queries at every location for 55 minutes on October 11, 2026. The postmortem, published October 20, puts the cause in a change that had shipped 25 days earlier and had not done anything since.

The shape of the failure is worth separating into three independent defects, because each one has a different fix and a different place in your own systems where it could be hiding.

Dns on Kuldeep Pisda

Control D's Bad Setting Sat Dormant for 25 Days, Then a Fail-Closed Startup Check Turned One Reload Into a Fleet-Wide Outage