Answer

PROBLEM

The GFI Anti-spam Public Folders are able to receive external mails. This should not happen under normal circumstances. Therefore, an external sender can add entries to the blocklist and whitelist or even add specific emails as spam or as legitimate emails.

ENVIRONMENT

• GFI MailEssentials
• Microsoft Exchange 2007 or later

SOLUTION

The following are two solutions which resolve this issue. Only one of these two solutions needs to be implemented in order for the GFI Anti-spam Public Folders not to receive emails:

Solution 1 (recommended):

Add the email addresses of the GFI Anti-spam Public Folders to the GFI MailEssentials blocklist.

1. Open the GFI MailEssentials Configuration
2. Expland the Anti-Spam node > Custom Blocklist
3. Click Add
4. In the Email Address/Domain field enter the email of the public folder: addtowhitelist@domain.com
5. Select the Check MIME TO: 
6. Click Ok.
7. Repeat step 3 to step 6 for the email address of each Subfolder of the GFI Anti-Spam Folders

Solution 2:

Change the SMTP email address for the GFI Anti Spam Public Folders to an email address that does which cannot be resolved. Perform the following:

1. Open your Microsoft Exchange System Manager
2. Browse to the Folders > Public Folders.
3. Right-click GFI AntiSpam Folders > Properties
4. Under the email addresses tab, double click on the SMTP Address GFIAntiSpamPublicFolders@domain.com to edit the entry
5. Enter a fake email address, for example: fake@fake.com to disable the possibility of sending an e-mail Public Folders
6. Repeat step 3 to step 5 for each Subfolder of the GFI Anti-Spam Folders