We have a distribution list that we recently discovered was open to receiving e-mails from outside our organization.
We have turned this off so that you can only use the address from inside.
What I would like to do is have a transport rule that redirects any outside messages sent to this distribution list so they go to an internal Exchange contact (it's a SharePoint list)
I do not want to affect messages sent from inside the company.
I tried a transport rule with the following settings:
From: Outside the organization
Where Header: To contains SMTP address of distribution list
Redirect to Exchange contact
If I disable security on the distribution list this works but it doesn't work with security turned on.
How do I need to setup the rule for this to work? I don't care if the original sender gets the NDR back that the list is restricted.