# Flexible A/AAAA Record Matching

A records map domain names to IPv4 addresses, and AAAA records map to IPv6 addresses. Flexible matching allows you to verify specific IP addresses are configured while permitting customers to add additional addresses for load balancing, redundancy, or multi-CDN setups.

## Why Flexible A/AAAA Matching

Modern applications often use multiple IP addresses for high availability, geographic distribution, and failover. Exact matching becomes problematic when customers need to add or adjust their infrastructure.

### The Exact Matching Problem

```
POST https://api.dnsradar.dev/monitors

domain: api.piedpiper.com
  record_type: A
  expected_value: ["1.2.3.4", "5.6.7.8"]
  is_exact_match: true
```

If the customer adds a third server for load balancing (`9.10.11.12`), exact matching triggers a false `MISMATCH` alert.

## Enabling Flexible Matching

Use `is_exact_match: false` to verify your required IPs exist while allowing additional addresses:

```
POST https://api.dnsradar.dev/monitors

domain: api.piedpiper.com
  record_type: A
  expected_value: ["1.2.3.4", "5.6.7.8"]
  is_exact_match: false
```

## How It Works

With flexible matching for A/AAAA records, DNSRadar:

1. Verifies all IP addresses in your `expected_value` are present
2. Ignores additional IP addresses not in your list
3. Considers the monitor VALID as long as your required IPs exist
4. Triggers `MISMATCH` only if required IPs are removed


## Valid Configurations

With the flexible configuration above, these A record sets would all be VALID:

```
# Exactly your IPs
1.2.3.4
5.6.7.8

# With additional IPs
1.2.3.4
5.6.7.8
9.10.11.12

# Mixed with many others
1.2.3.4
5.6.7.8
10.20.30.40
50.60.70.80
100.110.120.130
```

All contain your required IP addresses `1.2.3.4` and `5.6.7.8`, so they pass validation.

## IPv6 (AAAA) Monitoring

Flexible matching works identically for IPv6 addresses:

```
POST https://api.dnsradar.dev/monitors

domain: piedpiper.com
  record_type: AAAA
  expected_value: ["2001:db8::1", "2001:db8::2"]
  is_exact_match: false
```

## When Monitors Trigger

A `MISMATCH` alert is triggered if:

- One or more of your required IP addresses are removed
- All A/AAAA records are removed
- DNS query returns an error


> ✅ **SUCCESS:** **IP Additions Safe**: Adding new IP addresses never triggers alerts with flexible matching, enabling customers to scale their infrastructure freely.

## Common Use Cases

### CDN and Origin Monitoring

Ensure your origin server remains configured while allowing CDN IPs:

```
POST https://api.dnsradar.dev/monitors

domain: cdn.piedpiper.com
  record_type: A
  expected_value: ["203.0.113.10"]
  is_exact_match: false
  group: cdn-configuration
```

### Dual Stack Monitoring

Monitor both IPv4 and IPv6:

```
POST https://api.dnsradar.dev/monitors/bulk

monitors:
    - domain: piedpiper.com
      record_type: A
      expected_value: ["1.2.3.4"]
      is_exact_match: false
    - domain: piedpiper.com
      record_type: AAAA
      expected_value: ["2001:db8::1"]
      is_exact_match: false
  group: dual-stack-monitoring
```

### Load Balancer Configuration

Ensure specific load balancer IPs remain configured:

```
POST https://api.dnsradar.dev/monitors

domain: app.piedpiper.com
  record_type: A
  expected_value: ["10.0.1.100", "10.0.2.100"]
  is_exact_match: false
```

### Multi-Region Deployment

Monitor presence of regional endpoints:

```
POST https://api.dnsradar.dev/monitors

domain: api.piedpiper.com
  record_type: A
  expected_value: ["52.0.0.1", "13.0.0.1", "18.0.0.1"]
  is_exact_match: false
  frequency: 5
```

## Best Practices

1. **Monitor Critical IPs Only**: Specify only the IP addresses essential to your service
2. **Use Flexible Matching by Default**: Enable it unless you need strict IP control
3. **Combine with Health Checks**: DNS monitoring verifies configuration; use separate health checks for service availability
4. **Monitor Both IPv4 and IPv6**: Create separate monitors for A and AAAA records
5. **Group Related Monitors**: Organize monitors by service or infrastructure component

## Advanced Scenarios

### Anycast IP Monitoring

Verify anycast IPs are advertised:

```
POST https://api.dnsradar.dev/monitors

domain: anycast.piedpiper.com
  record_type: A
  expected_value: ["192.0.2.1"]
  is_exact_match: false
  frequency: 5
```

### Subnet Monitoring

Monitor multiple IPs from the same subnet:

```
POST https://api.dnsradar.dev/monitors

domain: cluster.piedpiper.com
  record_type: A
  expected_value: ["10.0.1.10", "10.0.1.11", "10.0.1.12"]
  is_exact_match: false
```

### Failover Configuration

Ensure both primary and failover IPs exist:

```
POST https://api.dnsradar.dev/monitors

domain: service.piedpiper.com
  record_type: A
  expected_value: ["203.0.113.10", "203.0.113.20"]
  is_exact_match: false
  group: high-availability
```

## Integration Examples

### Infrastructure as Code

```yaml
# Terraform/Pulumi example
monitors:
  - domain: api.example.com
    record_type: A
    expected_value:
      - 1.2.3.4  # Primary load balancer
      - 5.6.7.8  # Backup load balancer
    is_exact_match: false
    frequency: 5
    group: production-api
```

### Automated Monitoring Setup

```javascript
// Automatically monitor all production services
const services = await getProductionServices()

const monitors = services.map(service => ({
  domain: service.domain,
  record_type: service.ipv6 ? 'AAAA' : 'A',
  expected_value: service.criticalIPs,
  is_exact_match: false,
  frequency: 5,
  group: 'production-infrastructure'
}))

await dnsradar.monitors.bulkCreate({ monitors })
```

## Comparing Flexible vs Exact Matching

| Scenario | Exact Match | Flexible Match |
|----------|-------------|----------------|
| Customer adds IPs | ❌ MISMATCH | ✅ VALID |
| Customer removes required IP | ❌ MISMATCH | ❌ MISMATCH |
| Customer removes non-required IP | ❌ MISMATCH | ✅ VALID |
| IP order changes | ✅ VALID | ✅ VALID |
| All IPs removed | ❌ MISMATCH | ❌ MISMATCH |

## Monitoring Complete Service Stack

```
POST https://api.dnsradar.dev/monitors/bulk

monitors:
    - domain: piedpiper.com
      record_type: A
      expected_value: ["1.2.3.4"]
      is_exact_match: false
    - domain: www.piedpiper.com
      record_type: CNAME
      expected_value: piedpiper.netlify.app
    - domain: api.piedpiper.com
      record_type: A
      expected_value: ["10.0.1.100"]
      is_exact_match: false
    - domain: api.piedpiper.com
      record_type: AAAA
      expected_value: ["2001:db8::1"]
      is_exact_match: false
  group: service-infrastructure
  frequency: 5
```

## Next Steps

- [Managing MX Record Priorities](/docs/mx-priorities)
- [Bulk Update Monitors](/docs/update-monitors-bulk)
- [Configure Webhooks](/docs/configure-webhooks)