Hi,
We can try the following steps (supposing the \testPF is the Public Folder, Test1 is the user who want to send mails on behalf of that PF to the restricted DL, the domain is CU1.com):
1. Mail-Enable this Public Folder:
Enable-MailPublicFolder -Identity "\testPF"
2. Assign Send As permission to the user:
Add-ADPermission -Identity "CN=testPF,CN=Microsoft Exchange System Objects,DC=CU1,DC=com" -User Test1 -ExtendedRights "Send As"
3. Restart Microsoft Exchange Information Store service.
4. Add this Public Folder to the senders restricted list:
a.Run the following command in the Exchange Management Shell to create a new distribution group:
New-DistributionGroup "PFGroup"
b.Run the following command to add the public folder to the new distribution group:
Add-DistributionGroupMember -Identity "PFGroup" -Member "testPF@cu1.com"
c.Run the following command to add the new distribution group to the Only senders in the following list field of the target distribution group:
Set-DistributionGroup -Identity "DG10" -AcceptMessagesOnlyFromSendersOrMembers @{Add="PFGroup"}
Regards,