How to configure SPAM emails to be forwarded to a Microsoft Exchange public folder

Answer

Microsoft Exchange 2007 and later:

1. Create a public folder as explained at: http://technet.microsoft.com/en-us/library/aa997965.aspx
2. By default all users will be able to create items in this Public Folder. This can be confirmed using the get-publicfolderclientpermission cmdlet. More information can be found at: http://technet.microsoft.com/en-us/library/bb123881.aspx
3. Add relevant permissions for all users who will be moderating the emails blocked by GFI MailEssentials. This can be done using the Add-PublicFolderClientPermissions cmdlet. More information can be found at:
   http://technet.microsoft.com/en-us/library/bb310789.aspx
4. Mail-enable the public folder by running the Enable-MailPublicFolder cmdlet as explained at:
   http://technet.microsoft.com/en-us/library/bb691162.aspx
5. Create a new user from Microsoft Exchange Management Console -> Recipient Configuration -> Mailbox -> New Mailbox
6. In the Introduction page select User mailbox and click Next
7. In the User Type page select New User and click Next 
8. In the User Information page enter all relevant information for the mailbox and click Next 
9. In the New Mailbox page confirm the mailbox settings and click Next 
10. You need to configure mail forwarding so that emails addressed to the new mailbox are forwarded to the Public Folder. This needs to be done using the Set-Mailbox cmdlet from the Microsoft Exchange Management Shell. Microsoft Management console does not display Public folders for routing
    
    More information can be found at:
    http://technet.microsoft.com/en-us/library/bb851509.aspx

Microsoft Exchange 2000/2003

1. Create a public folder using Microsoft Exchange client or Microsoft Outlook
2. Give the necessary rights for all users to create elements in the folder as follows:
   • From Microsoft Outlook or a Microsoft Exchange client, right click on the Public Folder -> Properties
   • Go to Permissions and give the Default user the Author role and Anonymous the Contributor role
   • Add permissions for the users who will be moderating the emails blocked by GFI MailEssentials
   • Click Ok to apply the changes.
3. From Microsoft Exchange System Manager, select the newly created folder from Folders\Public Folders\
4. From the Actions menu, select Properties and then select the Microsoft Exchange Advanced tab.
5. Un-check Hidden from Microsoft Exchange address lists check box and click Ok
6. Create a new user using Active Directory Users & Computers
7. While in the user's properties, go to the Microsoft Exchange General tab, click on Delivery Options -> Forwarding address frame -> Modify button. Configure the Forwarding address to be the Public folders which you have created in the steps above
8. From the GFI MailEssentials configuration, configure this mailbox to receive all emails blocked as Spam by GFI MailEssentials