In Exchange 2003 it’s not possible to setup auto-forwarding to only forward emails received from a particular email address.
If you set up auto-forwarding in Exchange 2003 therefore, emails received from any email address will be forwarded to your provided email address.
Taking this into account, please note that you should create a separate test user in Exchange specifically to receive emails only from firstname.lastname@example.org and forward them back to it.
Step 1. Create a new user in MS Exchange 2003 Server to receive emails from email@example.com .
Select Action -> New -> User.
The New User window will open.
Fill-in data for the new user. Here we have created a new user with name “monitis ert”.
Check the Create an Exchange mailbox. Choose the Server and the Mailbox Store.
Step 2: Create a new MS Exchange contact with firstname.lastname@example.org email address.
Click Action -> New -> Contact.
The New Contact window will open.
Fill-in the new contact data. Click Next.
Check the Create an Exchange email address box.
Select the type of the email address and click OK.
Under the Email address enter: email@example.com.
Step 3. Configure the new MS Exchange user to forward all emails to the new contact.
Right-click on the user you have created to open Properties.
Click Delivery Options.
Select Forward to and click Modify.
Under the Enter the object name to select enter the contact that you have created (“ert monitis” in our example).
Back in Delivery Options click OK.
Setup is finished. All the emails sent to the new MS Exchange user you have created will be forwarded to firstname.lastname@example.org.