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DNS monitors require a hostname and support assertions against resolution results, response times, and specific record values.
Define this in code. YAML format · Terraform

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Config fields

FieldTypeRequiredDefaultDescription
config.hostnamestringYes—Domain name to resolve
config.recordTypesarray of stringNo["A"]Record types to query: A, AAAA, CNAME, MX, NS, TXT, SRV, SOA, CAA, PTR
config.nameserversarray of stringNosystem defaultCustom nameservers to query
config.timeoutMsintegerNo5000Per-query timeout in milliseconds
config.totalTimeoutMsintegerNo10000Total timeout for all queries in milliseconds

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Assertions

AssertionRequired fieldsDescription
dns_resolves(none)Passes if the hostname resolves at all
dns_response_timemaxMsFails if resolution takes longer than threshold
dns_response_time_warnwarnMsRecords degraded hint for elevated resolution time
dns_expected_ipsips (array)Fails if resolved IPs don’t match expected set
dns_expected_cnamevalueFails if CNAME target doesn’t match
dns_record_containsrecordType, substringFails if record value doesn’t contain substring
dns_record_equalsrecordType, valueFails if record value doesn’t match exactly
dns_txt_containssubstringFails if no TXT record contains substring
dns_min_answersrecordType, minFails if answer count is below minimum
dns_max_answersrecordType, maxFails if answer count exceeds maximum
dns_ttl_lowminTtlFails if TTL is below minimum
dns_ttl_highmaxTtlFails if TTL exceeds maximum

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Examples

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Basic resolution check

monitors:
  - name: Domain resolves
    type: DNS
    config:
      hostname: example.com
    assertions:
      - type: dns_resolves
        severity: fail

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Full validation with expected IPs

monitors:
  - name: Production DNS
    type: DNS
    config:
      hostname: api.example.com
      recordTypes: [A, AAAA]
      nameservers: ["8.8.8.8", "1.1.1.1"]
    frequencySeconds: 300
    regions: [us-east, eu-west]
    assertions:
      - type: dns_resolves
        severity: fail
      - type: dns_expected_ips
        ips: ["203.0.113.10", "203.0.113.11"]
        severity: fail
      - type: dns_response_time
        maxMs: 500
        severity: fail
      - type: dns_ttl_low
        minTtl: 60
        severity: warn

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SPF record validation

monitors:
  - name: SPF record
    type: DNS
    config:
      hostname: example.com
      recordTypes: [TXT]
    assertions:
      - type: dns_txt_contains
        substring: "v=spf1"
        severity: fail

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Next steps

DNS overview

When to use DNS monitors.

Regions

Available probe regions.