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DNS resolution method

General

The DNS resolution method does a DNS lookup (like nslookup using cmd). Only two queries are sent per test run that are trying to resolve the target hostname using the standard DNS server of a client. To respect caching only the response time of the second request is measured.

When to use the DNS resolution method

The DNS resolution method can be used to test the reachability of the standard DNS-Server and measures the response time. Due to caching only the second response is measured. The method exspects a valid response (e.g. no "Not found" response).

Parameters

These are the parameters that are configurable for each test using the DNS resolution method.

Hostname

Specifies the hostname of the target service.

Examples: example.comt, worldaz.tr.teams.microsoft.com

Warning/critical threshold

The thresholds define the latency beyond which a measurement gets the status warning or critical. Your standard DNS server usually responds in up to 20ms. If a response takes more than 50ms it is gernally slow and might indicate a misconfigured DNS server. The name resolution query times out after 15s.

Base warning threshold: 20ms Base critical threshold: 100ms Allowed inputs: 1 - 10.000 and the warning threshold has to be less than the critical threshold.

Example

Google name resolution test.

Limitations and recommondations

  • The DNS queries are using port 53 UDP without authentication. This test does not use 53/TCP as Fallback or DNSSEC.