EXO Diagnostics Toolkit

Production-style diagnostics scripts for Exchange Online / Microsoft 365 operations.

What this solves

• Fast mailflow triage with message trace details.
• Practical mailbox health checks (usage, quota, activity).
• Calendar permission diagnostics (sharing, delegates, processing).
• Lightweight M365 connectivity validation from terminal.

Toolkit

PowerShell

• powershell/mailflow-diagnostic.ps1
  • Message trace + detail extraction for sender/recipient path issues.
  • Optional incident metadata: -AffectedUser, -AffectedUserEmail.
• powershell/mailbox-health-check.ps1
  • Mailbox size, quota posture, activity timestamps, top folders.
  • Optional incident metadata: -AffectedUser, -AffectedUserEmail.
• powershell/calendar-health-check.ps1
  • Calendar permissions, delegate setup, sharing + processing checks.
  • Optional incident metadata: -AffectedUser, -AffectedUserEmail.

Bash

• bash/m365-connectivity-check.sh
  • DNS + HTTPS + SMTP STARTTLS probes for key M365 endpoints.

Requirements

• PowerShell 7+
• Module: ExchangeOnlineManagement
• Bash tooling (optional script): dig, curl, openssl

Quick usage

# Connect once
Connect-ExchangeOnline

# 1) Mailflow diagnostic
./powershell/mailflow-diagnostic.ps1 `
  -Sender sender@contoso.com `
  -Recipient user@contoso.com `
  -Hours 24 `
  -AffectedUser "Any User" `
  -AffectedUserEmail "any.user@contoso.com"

# 2) Mailbox health
./powershell/mailbox-health-check.ps1 `
  -Mailbox user@contoso.com `
  -AffectedUser "Any User" `
  -AffectedUserEmail "any.user@contoso.com"

# 3) Calendar health
./powershell/calendar-health-check.ps1 `
  -Mailbox user@contoso.com `
  -AffectedUser "Any User" `
  -AffectedUserEmail "any.user@contoso.com"

./bash/m365-connectivity-check.sh contoso.onmicrosoft.com

Output

• CSV/JSON exports for ticketing and post-incident notes.
• Console-friendly summaries for rapid first response.

Professional next steps

• Add transport rules and connector audit scripts.
• Add anti-spam / anti-phish policy snapshot.
• Generate unified HTML incident report.

Project hygiene

• MIT License
• Changelog
• Contributing Guide

SEO & AI Search Keywords

Primary search title: Exchange Online Diagnostics Toolkit (PowerShell + Bash)

Target keywords:

• exchange online diagnostics toolkit
• microsoft 365 troubleshooting scripts
• mailflow mailbox calendar health check
• powershell exchange tools

High-intent AI search questions:

• What toolkit helps triage Exchange Online incidents fast?
• How to run mailbox and calendar health checks?
• How to check Microsoft 365 connectivity from terminal?

On-page SEO notes:

• Keep issue-first headings (problem -> diagnosis -> next step).
• Include command examples with realistic placeholders only.
• Repeat key terms naturally in H1/H2, intro, and troubleshooting sections.
• Add incident outcome language: root cause, remediation, validation, prevention.