1. Uptime Monitoring
  2. Create a DNS monitor

Uptime Monitoring

Create a DNS monitor

DNS monitors check that a DNS record resolves the way you expect from OnlineOrNot's monitoring regions.

Use DNS monitors for:

  • Verifying production A, AAAA, CNAME, MX, NS, SOA, or TXT records.
  • Catching DNS provider outages or resolver-specific failures.
  • Confirming DNS answers after a migration.
  • Monitoring DNS records that power email, CDN, or load-balancer routing.

Create the monitor

Go to the checks dashboard, click Add check, then choose Monitor DNS.

Enter:

  • Check name: a name for this DNS monitor.
  • Domain: the DNS name to query, for example example.com.
  • Record type: one of A, AAAA, CNAME, MX, NS, SOA, or TXT.
  • Protocol: UDP or TCP.
  • DNS server: optional custom resolver, for example 1.1.1.1 or 1.1.1.1:53.
  • Test frequency: how often OnlineOrNot should run the DNS query.
  • Regions: where OnlineOrNot should run the DNS query from.

Click Save. The monitor starts in a pending state until OnlineOrNot runs the first DNS query.

DNS server behavior

If you leave DNS server blank, OnlineOrNot uses its default resolver failover.

If you enter a DNS server, OnlineOrNot sends the DNS query to that resolver only. Custom resolvers support:

  • IPv4 addresses, for example 1.1.1.1.
  • Hostnames, for example dns.google.
  • host:port, for example 1.1.1.1:53.
  • IPv6 bracket notation, for example [2606:4700:4700::1111]:53.

Assertions

Assertions let you fail the DNS monitor when the response is available but wrong.

DNS assertion types:

  • Response code: checks the DNS response status, for example NOERROR or NXDOMAIN.
  • Text answer: checks the raw DNS response text.
  • JSON answer: checks the parsed DNS response with JSONPath, for example $.answers[0].data.

Without a response-code assertion, DNS responses with NOERROR pass by default. Add a response-code assertion if you want to intentionally monitor for another status.

Results

DNS result rows show:

  • Pass/fail state.
  • DNS status.
  • Checked region.
  • Resolver.
  • Protocol.
  • Response time.
  • Retry/final-attempt metadata where applicable.

Open a result detail page to inspect the query summary, raw DNS response, parsed JSON response, transport errors, and assertion failures.

Limitations

It is not currently possible to alert using response-time thresholds.