Exchange Online PowerShell in 2026: The Commands You Actually Need
From Exchange Server to Microsoft 365
Moving from Exchange Server to Exchange Online changes more than where your mailboxes are hosted.
The biggest change is the administration model.
Exchange Server → Servers → Databases → DAGs → Queues → Mailboxes
Exchange Online → Users → Mailboxes → Permissions → Groups → Mail Flow → Policies
If you’re an Exchange administrator moving into Microsoft 365, you will quickly notice that some familiar PowerShell commands still work, some have newer Exchange Online-optimized alternatives, and others should simply be removed from your toolbox.
💡 The goal isn’t to memorize hundreds of commands. It’s to know the right command for the problem you’re trying to solve.
🔌 1. Connect to Exchange Online
Before running Exchange Online PowerShell commands, establish a connection to your Microsoft 365 tenant.
Connect-ExchangeOnline
When you’re finished:
Disconnect-ExchangeOnline
To check your current connection:
Get-ConnectionInformation
👥 2. Find Who Manages a Distribution Group
Need to find out who owns a distribution list?
Get-DistributionGroup -Identity "DL Name" | Format-List DisplayName,ManagedBy
For a cleaner table:
Get-DistributionGroup -Identity "DL Name" | Format-Table DisplayName,ManagedBy -Wrap
You can also search for groups managed by a specific person:
Get-DistributionGroup -ManagedBy "user@contoso.com"
📋 3. See Distribution Group Members
Finding the owner is only half the job. You may also need to see who belongs to the group.
Get-DistributionGroupMember -Identity "DL Name"
For a more useful report:
Get-DistributionGroupMember -Identity "DL Name" | Format-Table Name,PrimarySmtpAddress,RecipientType
📬 4. Give a User Full Access to a Mailbox
This remains one of the most common Exchange Online administration tasks.
Add-MailboxPermission ` -Identity "shared@contoso.com" ` -User "user@contoso.com" ` -AccessRights FullAccess ` -InheritanceType All
If you don’t want Outlook to automatically map the mailbox:
Add-MailboxPermission ` -Identity "shared@contoso.com" ` -User "user@contoso.com" ` -AccessRights FullAccess ` -InheritanceType All ` -AutoMapping $false
$false prevents automatic Outlook mapping.
✉️ 5. Give Send As Permission
This is an important difference for administrators coming from on-premises Exchange.
❌ Old Exchange Server approach
Add-ADPermission
✅ Exchange Online approach
Add-RecipientPermission ` -Identity "shared@contoso.com" ` -Trustee "user@contoso.com" ` -AccessRights SendAs
Verify the permission:
Get-RecipientPermission ` -Identity "shared@contoso.com" ` -Trustee "user@contoso.com"
Full Access
The user can open and work with the mailbox.
Send As
The user can send messages that appear to come directly from that mailbox.
🔎 6. Check Mailbox Size
Exchange Online administrators should become familiar with the Exchange Online optimized cmdlets.
Get-EXOMailboxStatistics ` -Identity "user@contoso.com"
For more information:
Get-EXOMailboxStatistics ` -Identity "user@contoso.com" | Format-List DisplayName,ItemCount,TotalItemSize,TotalDeletedItemSize
- Mailbox size
- Item count
- Deleted-item size
📊 7. Find Large Mailboxes
Need to identify users with unusually large mailboxes?
Get-EXOMailbox -ResultSize Unlimited |
ForEach-Object {
Get-EXOMailboxStatistics -Identity $_.UserPrincipalName
} |
Sort-Object TotalItemSize -Descending |
Select-Object DisplayName,TotalItemSize,ItemCount
🔁 8. Check and Configure Mailbox Forwarding
Mailbox forwarding is another common support request.
Check the current configuration:
Get-Mailbox "user@contoso.com" | Format-List ForwardingAddress,ForwardingSmtpAddress,DeliverToMailboxAndForward
To configure forwarding:
Set-Mailbox ` -Identity "user@contoso.com" ` -ForwardingAddress "manager@contoso.com" ` -DeliverToMailboxAndForward $true
📁 9. Manage Exchange Online Public Folders
Public folders are still used by many organizations.
To give a user Publishing Editor permission:
Add-PublicFolderClientPermission ` -Identity "\IT" ` -User "user@contoso.com" ` -AccessRights PublishingEditor
Check the permission:
Get-PublicFolderClientPermission ` -Identity "\IT" ` -User "user@contoso.com"
📅 10. Configure Calendar Processing
Resource and shared mailboxes often require customized calendar-processing settings.
Set-CalendarProcessing ` -Identity "meetingroom@contoso.com" ` -DeleteSubject $false ` -AddOrganizerToSubject $false
Check the current configuration:
Get-CalendarProcessing ` -Identity "meetingroom@contoso.com"
🗑️ 11. Investigate Recoverable Items
Don’t simply copy old Exchange Server dumpster-export procedures into Exchange Online.
For investigation, use mailbox folder statistics:
Get-EXOMailboxFolderStatistics ` -Identity "user@contoso.com" ` -FolderScope RecoverableItems
This can help investigate Recoverable Items usage, deleted-item volume and retention-related storage.
🔍 12. Troubleshoot Mail Flow With Message Trace
This is one of the biggest mindset changes when moving from Exchange Server to Exchange Online.
❌ Don’t troubleshoot Microsoft’s backend transport servers with:
Get-Queue
Instead, start with message tracing.
Get-MessageTrace ` -SenderAddress "user@contoso.com" ` -StartDate "08/14/2026" ` -EndDate "08/15/2026"
💡 The mindset change:
You troubleshoot the message journey, rather than Microsoft’s underlying transport servers.
❌ 13. Exchange Server Commands You Should Remove
A lot of old Exchange PowerShell articles mix on-premises commands with Exchange Online commands. That can be confusing for administrators.
❌ DAG Database Health
Get-MailboxDatabaseCopyStatus
DAG and database-copy management is an Exchange Server administration task. Exchange Online customers don’t manage Microsoft’s underlying mailbox database copies.
❌ Transport Queue Management
Get-Queue
Exchange Online administrators don’t manage Microsoft’s backend transport queues.
❌ Mailbox Export Requests
New-MailboxExportRequest
Get-MailboxExportRequest
These are Exchange Server concepts and should not be presented as Exchange Online commands.
🧠 The Biggest Mindset Change
Exchange Server
↓
DATABASE
↓
DAG
↓
QUEUE
↓
MAILBOX
Exchange Online
↓
EXCHANGE ONLINE
↓
MAILBOX / GROUP
↓
POLICY / PERMISSION
↓
USER
Microsoft operates the underlying Exchange Online infrastructure. Your responsibility is primarily configuration, identity, permissions, policies, security and workloads.
🚀 Your Essential Exchange Online Toolkit
If you’re building a practical PowerShell toolkit for Microsoft 365 administration, start with these commands:
# Connection Connect-ExchangeOnline Disconnect-ExchangeOnline # Groups Get-DistributionGroup Get-DistributionGroupMember # Mailboxes Get-EXOMailbox Get-EXOMailboxStatistics Get-EXOMailboxFolderStatistics # Permissions Add-MailboxPermission Get-MailboxPermission Add-RecipientPermission Get-RecipientPermission # Public Folders Add-PublicFolderClientPermission Get-PublicFolderClientPermission # Calendar Set-CalendarProcessing Get-CalendarProcessing # Mail Flow Get-MessageTrace
🎯 Final Thought
Exchange Online is not simply Exchange Server hosted in Microsoft’s cloud.
The administration philosophy has changed.
You’re no longer spending your day asking:
“Which database is unhealthy?”
You’re more likely asking:
“Who has access to this mailbox?”
“Why isn’t this message arriving?”
“Who owns this distribution group?”
“Why is this mailbox so large?”
“Why isn’t forwarding working?”
Less infrastructure. More service management.
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