Configure Message Delivery Restrictions on a resource mailbox in Exchange 2016

We just recently migrated from Exchange 2010 to 2016. In addition to our user mailboxes we also migrated a couple dozen conference room mailboxes or resource mailboxes as they are referred to in Exchange 2016.

All our conference rooms are set to auto booking for everyone except on a particular conference room that is reserved for the executives. Only the executives and their administrative assistants are allowed to book meetings to this conference room.

To limit the other employees for booking the executive conference room I used the Message Delivery Restrictions, Accept Messages From, Only Senders in the Following List option in Exchange 2010. I have eight people in the list.

Since our move to Exchange 2016 we have had one executive leave the company, one executive admin leave the company, and one admin change responsibilities to cover for the one admin that left. I needed to make the changes to the Only Senders in the Following List option for the executive conference room.

After much searching in Exchange 2016 I could not find any place where these setting could be modified in the Exchange Management Console. In the Resources tab under Recipients I found the resource but when I went to edit the room there was no setting for Message Delivery Restrictions.

Command line to the rescue. Open the Exchange Management Shell. 

Step #1 - Get Resource properties

Using the command: get-mailbox -Identity "Resource name" | fl I was able to see the parameters that contained the users who had access to send emails to the resource room. The parameter “AcceptMessagesOnlyFrom” listed all the names with access.

To narrow the search down I used this command:

get-mailbox -Identity "Resource name" | fl “AcceptMessagesOnlyFrom”

Step #2 – Added New Admin

Set-Mailbox -Identity "Resource name" -AcceptMessagesOnlyFrom @{Add="user@domain.com"}

Step #3 – Remove Departed Users

Set-Mailbox -Identity "Resource name" -AcceptMessagesOnlyFrom @{Remove="user@domain.com"} 

If you need to add or remove multiple users then just add a comma in between the name.

@{Add="<value1>","<value2>"...; Remove="<value1>","<value2>"...}

That’s it. Very simple after quite a bit of digging. I hope this helps.