DNS monitoring
One record type asked for every minute. No answer is down; an answer without the text you expect is down too, which catches a record that quietly changed.
Northwind is up.
The monitor is responding, 4 failed checks in the last 24 hours.
A record for northwind.example
Up for 24 min99.72% passed
1,438 checks, median 19 ms, 4 failed checks
95% under 26 ms
- Failed4 min, 4 checks
How the check works
A DNS monitor asks for one record type for a name: A, AAAA, CNAME, MX, TXT or NS. It passes when at least one answer comes back within the timeout. Set text the answer must contain and the check also fails when the record is there but wrong: an A record that no longer points at your load balancer, an MX record a migration overwrote, a TXT record for SPF or domain verification that someone tidied away, an NS record pointing at the old provider. The response time recorded is how long the lookup took.
Most outages that start with DNS look like something else first: the site is fine from the office because the old answer is cached, and down for everyone whose resolver asked after the change. A DNS monitor names the cause on the strip, next to the website monitor that only saw a connection error.
When it counts as down
A DNS monitor counts as down after two failed checks in a row and as back after one success. Before a failure counts, it is checked again in the same region; only a failure both checks see goes on the record. On Hobby and Pro every other region checks at the same moment, so the page can say down from North America instead of down. A single failed check still appears on the strip with its time and reason, it just does not change the state or send an alert.
Alerts
Each change of state sends one alert: down, and back, with how long it was out. Email is on every plan. Hobby and Pro add Slack, Discord, Microsoft Teams, Telegram, PagerDuty, Opsgenie, Pushover, ntfy and a signed webhook, plus a repeat notice every so many minutes while an outage lasts. Nothing is sent during a maintenance window.
What the status page shows
Every DNS monitor gets a strip on the public page. Each bar is one check, its height the response time; amber marks a timeout and red any other failure. Consecutive failures are grouped into one entry with the time and the reason, and the mark stays there for the whole range. A DNS monitor going down opens an incident on the page by itself and resolves it on recovery.