Create Redirect Rule for Specific Mail ID

Available Actions in Mail Flow Rules:

1. Redirect the message to — message goes only to the new recipient (original does not receive it)

2. Add recipient > Bcc the message to — message is delivered to both the original recipient and the Bcc'd address

Steps:

1. Go to Exchange Admin Center → Mail Flow → Rules (https://admin.exchange.microsoft.com)

2. Click + Add a rule

3. Name your rule: Forward RTA Mails to [e-mail]

4. Conditions:

   • Apply this rule if...

     • The recipient is → [e-mail]

     • The sender is → Add:

       • [e-mail]

       • [e-mail]

5. Do the following...

   • Choose: "Add recipient" → "Bcc the message to" → [e-mail]

6. Leave audit/logging defaults and save the rule.

Result

• The message is delivered normally to [e-mail]

• A copy is silently Bcc’d to [e-mail]

• The original sender is not notified

Enable External Email Forwarding in Microsoft 365

Some tenants have automatic external forwarding disabled by default (for security reasons). To allow it:

Go to:

https://security.microsoft.com → Email & Collaboration > Policies & Rules → Threat policies > Anti-spam policies

Find the active policy (often named "Default").

1. Click the policy → Edit outbound spam filter policy

2. Scroll to Automatic forwarding

3. Set to: On - Forwarding is enabled

4. Click Save

Add the External Email as a Mail Contact (Optional but Recommended)

If you want to use the external address ([e-mail]) in mail flow rules, it’s best to add it as a mail contact:

In Exchange Admin Center (https://admin.exchange.microsoft.com):

1. Go to Recipients > Contacts

2. Click + Add a mail contact

   • Name: RTA Contact

   • Email: [e-mail]

3. Save

Now this external address will show up as a selectable recipient in mail flow rules.

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REFERENCES

https://learn.microsoft.com/en-us/microsoft-365/admin/email/configure-email-forwarding?view=o365-worldwide