# DNS Resolution Outage Incident Summary (2026)

## Incident Overview

### Service Affected

DNS Resolution Services

### Impact Duration

12 Minutes

### Affected Systems

6 Lab Devices

## Incident Detection

The outage was identified through a combination of user-reported connectivity issues and monitoring alerts indicating failed DNS lookups.

## Initial Symptoms

* Internal hostnames failed to resolve.
* External internet domains failed to resolve.
* Client systems experienced intermittent connectivity symptoms despite active network connections.

## Investigation Activities

```powershell
Resolve-DnsName server01.ad.jeremyfontenot
Resolve-DnsName microsoft.com
Clear-DnsClientCache
Restart-Service DNS -WhatIf
```

### Evidence Collected

* Monitoring alerts
* DNS lookup failures
* Resolver cache validation
* Service restart testing
* Device impact assessment

### Sanitization

All hostnames, IP references, and environment details are lab-safe and do not contain production identifiers, credentials, or sensitive information.

## Root Cause Analysis

### Root Cause

Misconfigured DNS forwarder settings prevented successful external name resolution.

### Contributing Factors

* Configuration drift during testing activities
* Lack of automated DNS health validation

## Corrective Actions

* Corrected DNS forwarder configuration
* Cleared DNS resolver cache
* Validated DNS service status
* Performed internal and external resolution testing

## Validation

### Internal Resolution Test

```powershell
Resolve-DnsName server01.ad.jeremyfontenot
```

Result: Successful

### External Resolution Test

```powershell
Resolve-DnsName microsoft.com
```

Result: Successful

## Lessons Learned

* Implement automated DNS health monitoring.
* Expand configuration review procedures.
* Validate forwarder configuration after maintenance activities.

## Result

DNS functionality was restored successfully. Internal and external name resolution returned to normal operation and all affected devices resumed expected connectivity.