Restricting mailboxes to accept messages from specific external senders

Question

Here's the scenario: I have an MS Exchange distribution list called SMT. Currently, msExchRequireAuthToSendTo is set to true, so this list will not accept emails from external senders. We recently hired a new VP of something, and he uses an external email address, so he can't send to SMT.

After some Googling, I've discovered the authOrig and dlMemSubmitPerms attributes, which authorizes a list of senders, and members of a list of distribution lists respectively. I created an MS Exchange contact for the new VP's external address and added that to the authOrig list. Then I added the company wide distribution list to dlMemSubmitPerms. Finally, I set msExchRequireAuthToSendTo to false.

The company employees can send to SMT, but the external address still cannot. Is it because authOrig only works with MS Exchange users and not contacts?

According to Understanding Recipient Restrictions you can:

use this restriction ... for mail contacts that represent suppliers for a retail organization. You may want to configure each of these mail contacts to accept messages from only the buyers who work directly with those suppliers.

How can I accomplish this? (I know that the easiest solution is to make the VP use his internal address, but if I can cater to his wants, I'll get brownie points.) Thanks.

Solution

Nothing like a nearly-year-late answer. Being that I'm so late, you probably have this working already.

The settings you've mentioned should work exactly as you want, though I will admit that I rarely, if ever, set the AD attributes directly. This is very easy to do within the Exchange PowerShell module (on Exchange 2007 / 2010).

Set-DistributionGroup [your_distribution_group] -RequireSenderAuthenticationEnabled $false -AcceptMessagesOnlyFrom [contact] -AcceptMessagesOnlyFromDLMembers [company-wide_distribution_group]

If it's still not working, could you post the NDR error the contact is receiving when trying to send?