Email forwarding in Exchange Online allows an incoming email to be automatically sent to another internal or external mailbox. Forwarding can be configured by the admin using the Exchange Admin Center or by the user in Outlook. Admin-controlled forwarding is most commonly used for departed employees, generic mailboxes, shared mailboxes, and service accounts.

⭐ Use Cases for Email Forwarding

✔ 1. Departed Employees

Forward emails to a manager or HR mailbox while the account is disabled.

✔ 2. Role-based Addresses

Forward sales@, billing@, or info@ to multiple recipients or a shared mailbox.

✔ 3. Service Accounts

Forward notifications from legacy systems to operational teams.

✔ 4. Business Continuity

Forward to backup mailboxes during migrations or outages.

? Security Considerations

Forwarding to external domains should be restricted due to:

• Data leakage risks

• Account compromise scenarios

• Spam and phishing forwarding risks

• Compliance and legal issues

? Most secure tenants block external forwarding globally.

Always review your policy before enabling forwarding to external mailboxes.

✔ Method 1 — Admin Forwarding (Recommended)

Using Exchange Admin Center (EAC)

Step 1: Open Exchange Admin Center

1. Go to https://admin.exchange.microsoft.com

2. Open Recipients → Mailboxes

3. Select the mailbox

4. Click Mail Flow (or Manage mail flow settings)

Step 2: Enable Forwarding

1. Turn on Forward all emails

2. Enter the target email address

   • Internal mailbox

   • Shared mailbox

   • Distribution list

3. (Optional) Check Keep a copy of forwarded messages

4. Save

✔ Method 2 — Forwarding Using Inbox Rules (User-Based)

Set by end users from Outlook or OWA.

Outlook Web

1. Go to Outlook → Settings → Mail → Rules

2. Create rule:

   • Condition: Apply to all messages

   • Action: Forward to

3. Save

Outlook Desktop

1. Home → Rules → Manage Rules

2. New Rule → Apply to incoming messages

3. Choose Forward to

4. Save

⚠️ These rules may bypass certain admin controls but are restricted by external forwarding policies.

✔ Method 3 — Distribution Lists & Shared Mailboxes

Forward a shared mailbox automatically

Use Mail flow rules or routing settings.

Forward a distribution group

1. Teams & Groups → Active

2. Select the group

3. Delivery management → Add forwarding
   (availability varies by group type)

? Forwarding to External Domains — Requirements

External forwarding must be enabled under:

Microsoft 365 Defender → Policies → Anti-Spam Outbound

• Outbound spam policy:
  Automatic forwarding → ON or On to external recipients

By default, most tenants block external forwarding.

?️ Troubleshooting

❗ Forwarding not working

• External forwarding is blocked

• Recipient blocked or mailbox disabled

• Forwarding address not valid

• Conflicting inbox rule exists

• Mail flow rule overrides forwarding

• Hybrid server routing issues

❗ Keep a copy not working

• Mailbox is full

• Retention policy deleting emails

• Inbound connector restrictions