Network Preflight

An Azure DevOps Pipelines extension that validates network connectivity from the build/release agent before critical deployments. This helps you catch DNS, HTTP, or TCP connectivity issues early in your pipeline.

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✅ Why use Network Preflight?

Detect firewall or DNS issues before production releases.
Validate critical endpoints (APIs, databases, identity providers) from the actual agent environment.
Reduce deployment failures caused by network misconfigurations.

🚀 Features

HTTP(S) Check
Validate URLs for reachability, status codes, latency, and optional header checks.
DNS Lookup
Resolve A/AAAA/CNAME/TXT/NS records with optional custom DNS resolver.
TCP Probe
Test raw TCP connectivity to host:port with optional TLS and SNI support.

📦 Tasks Overview

Task Name	Purpose	Key Inputs
`HttpCheck@1`	Validate HTTP(S) endpoints	`targets`, `method`, `expectStatus`
`DnsLookup@1`	Resolve DNS records	`targets`, `recordType`, `resolver`
`TcpProbe@1`	Test TCP connectivity (TLS optional)	`targets`, `useTls`, `serverName`

All tasks run on Node 20 (current Azure Pipelines guidance).

🛠 Inputs (Common)

targets: Multi-line list of endpoints (URLs or host:port).
timeoutSeconds: Timeout per check (default: 10).
failOn (future enhancement): Control failure behavio

YAML example

pool:
  vmImage: 'ubuntu-latest'

steps:
  - task: HttpCheck@1
    inputs:
      targets: |
        https://contoso.com/health
        https://learn.microsoft.com
      method: HEAD
      timeoutSeconds: 10
      expectStatus: 200-399

  - task: DnsLookup@1
    inputs:
      targets: |
        contoso.com
      recordType: A

  - task: TcpProbe@1
    inputs:
      targets: |
        contoso.com:443
      useTls: true

⚠️ Support Disclaimer

This extension is not an officially supported Microsoft product — for issues or feature requests, please create a GitHub issue in the https://github.com/microsoft/Network_Preflight-Extension instead of opening a Microsoft Support request. It is developed and published independently by Microsoft support engineers to assist customers and internal support teams with troubleshooting network connectivity scenarios in Azure DevOps Pipelines. This extension is provided as-is, without any warranties or guarantees of support from Microsoft. Use of this extension in production environments should follow your organization's internal validation and governance processes.