Azure DevOps – Network Preflight (HTTP/DNS/TCP)

Validate HTTP, DNS, and TCP connectivity from your build/release agents before critical deployments. Catch network issues early, fail fast, and ship with confidence.

✅ 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 headers.
DNS Lookup
Resolve A/AAAA/CNAME records with optional expected target validation.
TCP Probe
Test raw TCP connectivity to host:port with configurable retries and timeouts.

📦 Tasks Overview

Task Name	Purpose	Key Inputs
`HttpCheckV1`	Validate HTTP(S) endpoints	`url`, `method`, `expectedStatus`
`DnsLookupV1`	Resolve DNS records	`hostname`, `expectedRecordType`
`TcpProbeV1`	Test TCP connectivity	`host`, `port`, `timeoutSeconds`

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

✅ 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

AzureDevOpsCSS-Network Preflight