Summary:

You want to block mail for addresses that don't really exist at your domain.

Detailed Information:

By default, EMF will accept messages for any address at your domain that you do not explicitly block. So, mail will be passed for addresses that may not really exist. Your internal mail server will either reject or return these messages.

To have EMF reject or return the messages rather than passing them, see below.

Resolution:

In order to block all messages for non-existent users, you will first need to identify all legitimate users, then set a policy to block all mail to the domain (except when sent to those legitimate users).

1. Add a user record to the EMF directory for every legitimate user. These should go into a subfolder you create below internal (note that EMF supports LDAP/LDIF imports for importing all your users).
   
   
2. Once every user is identified to EMF, write a RECIPIENT based policy with no CATCH conditions with the ACTION you desire (i.e., Drop or return to sender):
   

   Policy Type: Basic Mail Filtering
   Applies To: Recipient
   
   Summary of policy, ready to save:
   
   Take the following actions...
   Drop the message

3. Edit the Internal folder, and add the policy to that domain record. Be sure to click SAVE so the change takes effect.
   
   
4. Edit the subfolder you created in step 1 and DISABLE the new policy on that subfolder. Be sure to click SAVE so the change takes effect.
   
   
5. The policy will apply to ANY domain or user in the Internal folder EXCEPT for those in the subfolder where you've disabled it. If you have more than one domain in the Internal folder, and you wish to do non-existent recipient blocking for only SOME of the domains, move the other domains into the subfolder that has the policy disabled OR edit the other domains and explicitly disable the policy on those domains.

The result will be:

• for any message sent to a user with a user record, the policy will NOT be located, the user will receive the e-mail
  
• for any message sent to a user with NO user record, the domain record will be found, and the policy will cause the message to be dropped.

NOTE: You MUST remember to add new records for each new employee or they will be unable to receive mail. You should also delete records for employees who have left the company.

Additional Info:

If your user directory is available on an LDAP server or in an LDIF file format, you can import the user records using the EMF "Import Directory" functionality. See the Administrators guide for information on setting up directory importing.