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Exchange Admin Center (EAC) has introduced a streamlined approach to email forwarding, making it easier for admins to manage internal and external forwarding rules.
Key Improvements:
🕒 Earlier:
- Single forwarding field (
ForwardingAddress). - No distinction between internal/external addresses.
- External SMTP required PowerShell configuration.
- Forwarding conflicts were hard to detect.
🆕 Now:
✅ Separate fields for internal and external forwarding.
✅ Admins can only set one forwarding path (internal or external).
✅ External SMTP forwarding now available in the UI.
🔔 Heads-Up:
- Mailbox owners can still modify external forwarding via Outlook but not internal.
- If internal forwarding is active, adding an external address in Outlook won’t override it—internal takes precedence.
You Should Know:
1. Configuring Forwarding in EAC (GUI Method)
1. Open Exchange Admin Center (EAC).
2. Navigate to Recipients > Mailboxes.
- Select a mailbox and click Edit (pencil icon).
4. Go to Mailbox Features > Mail Flow.
- Choose Internal Forwarding (for same org) or External SMTP Forwarding.
6. Enter the target email and Save.
2. PowerShell Method (Legacy & Advanced Control)
Check current forwarding settings Get-Mailbox [email protected] | Select ForwardingAddress, ForwardingSmtpAddress Set internal forwarding Set-Mailbox [email protected] -ForwardingAddress "[email protected]" Set external SMTP forwarding Set-Mailbox [email protected] -ForwardingSmtpAddress "[email protected]" Disable forwarding Set-Mailbox [email protected] -ForwardingAddress $null -ForwardingSmtpAddress $null
3. Detecting Conflicts (PowerShell)
Find mailboxes with both forwarding types (potential conflict)
Get-Mailbox -ResultSize Unlimited | Where { $<em>.ForwardingAddress -ne $null -and $</em>.ForwardingSmtpAddress -ne $null }
4. Linux/Mac Alternative (Using curl for SMTP Testing)
Test external SMTP forwarding (via Telnet) telnet mx.example.com 25 EHLO yourdomain.com MAIL FROM:<a href="mailto:sender@domain.com">sender@domain.com</a> RCPT TO:<a href="mailto:forwardeduser@example.com">forwardeduser@example.com</a> DATA Subject: Test Forwarding This is a test email. . QUIT
What Undercode Say:
This update simplifies Exchange email management, reducing misconfigurations. However, PowerShell remains essential for bulk operations and validation. For security:
– Audit forwarding rules regularly:
Get-Mailbox -ResultSize Unlimited | Select Name,ForwardingAddress,ForwardingSmtpAddress | Export-Csv "ForwardingReport.csv"
– Block suspicious forwarding (e.g., to unknown domains):
Set-RemoteDomain Default -AutoForwardEnabled $false
– Monitor logs for unauthorized changes:
grep "Set-Mailbox" /var/log/exchange_audit.log
For hybrid setups, ensure on-premises Exchange syncs correctly:
Get-HybridConfiguration | Test-HybridConnectivity
Expected Output:
A structured guide combining EAC UI steps, PowerShell commands, and Linux-based verification methods for Exchange email forwarding.
References:
Reported By: Jake Admindroid – Hackers Feeds
Extra Hub: Undercode MoN
Basic Verification: Pass ✅
