Your First DNS Monitor

By the end of this guide, you’ll have a DNS monitor checking that your domain resolves correctly and returns the expected records.

Prerequisites

DevHelm CLI installed or an API token for REST calls
An API token set as DEVHELM_API_TOKEN — see Authentication
A domain name to monitor

Create the monitor

Create the DNS monitor

devhelm monitors create \
  --name "example.com DNS" \
  --type DNS \
  --url example.com \
  --frequency 300 \
  --regions us-east,eu-west

version: "1"
monitors:
  - name: example.com DNS
    type: DNS
    config:
      hostname: example.com
      recordTypes:
        - A
        - AAAA
    frequencySeconds: 300
    regions:
      - us-east
      - eu-west

curl -X POST https://api.devhelm.io/api/v1/monitors \
  -H "Authorization: Bearer $DEVHELM_API_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "example.com DNS",
    "type": "DNS",
    "config": {
      "hostname": "example.com",
      "recordTypes": ["A", "AAAA"]
    },
    "frequencySeconds": 300,
    "regions": ["us-east", "eu-west"]
  }'

With the CLI, --url is the hostname to resolve and default record types apply. To check specific record types, set config.recordTypes via YAML config-as-code or the API, as shown in the other tabs.

Verify it's running

devhelm monitors list --type DNS
devhelm monitors get <monitor-id>

Check results

Results include resolved records, query time, and the nameserver used.

devhelm monitors checks <monitor-id> --limit 5

Add assertions

Verify that DNS returns the records you expect:

monitors:
  - name: example.com DNS
    type: DNS
    config:
      hostname: example.com
      recordTypes:
        - A
    frequencySeconds: 300
    regions:
      - us-east
    assertions:
      - config:
          type: dns_resolves
        severity: fail
      - config:
          type: dns_expected_ips
          ips:
            - "93.184.216.34"
        severity: fail
      - config:
          type: dns_response_time
          maxMs: 500
        severity: warn

Key DNS assertions:

Type	What it checks
`dns_resolves`	The domain resolves to at least one record
`dns_expected_ips`	Resolved IPs match an expected list
`dns_record_count`	Number of returned records matches expectations
`dns_response_time`	Query completes within a threshold

For the full list (12 assertion types), see DNS configuration.

Common use cases

DNS migration validation

After changing DNS providers, verify that all regions resolve to the correct IPs. Run from multiple regions to catch propagation issues.

CDN failover detection

Monitor CNAME records that point to your CDN. If the CNAME changes unexpectedly, an assertion failure triggers an incident.

MX record monitoring

Verify that MX records are present and point to the correct mail servers to catch email delivery issues early.

Next steps

DNS monitor reference

All DNS configuration options and record types.

First alert

Get notified when DNS resolution fails.

Multi-region monitoring

Detect region-specific DNS issues.

Overview

Getting Started

Monitoring Guides

Alerting Guides

Incident Guides

Status Data Guides

Monitoring as Code Guides

Your First DNS Monitor

Create the monitor

Add assertions

Common use cases

Next steps

DNS monitor reference

First alert

Multi-region monitoring

​Create the monitor

​Add assertions

​Common use cases

​Next steps

DNS monitor reference

First alert

Multi-region monitoring

Create the monitor

Add assertions

Common use cases

Next steps