Problem: When you send an email to a distribution that was created in Exchange Server 2010 it works inside the domain. If you send an email from an outside, the email bounces with an error.
The error says
Delivery has failed to these recipients or groups:
Your message can't be delivered because delivery to this address is restricted.
Diagnostic information for administrators:
Generating server: example.com
email@example.com #550 5.7.1 RESOLVER.RST.AuthRequired; authentication required ##
This issue occurs because the Require that all senders are authenticated option is enabled on the Distribution Group. By default, this option is enabled for any new Distribution Groups that are created in Exchange 2010 or Exchange 2007.
To resolve this issue, use one of the following methods, as appropriate for your situation.
Method 1: Use Exchange Management Console
- Click Start, click All Programs, click Microsoft Exchange Server 2010, and then click Exchange Management Consoleto open Exchange Management Console.
- In the Exchange Management Console tree, click Recipient Configuration, and then click Distribution Group.
- In the result pane, right-click the affected Distribution Group, and then click Properties.
- On the Mail Flow Settings tab, click Message Delivery Restrictions, and then click Properties.
- Click to clear the Require that all senders are authenticated option check box, and then click OK.
- Force replication among the domain controllers.
Method 2: Use Exchange Management Shell
- Click Start, click All Programs, click Microsoft Exchange Server 2010, and then click Exchange Management Shell to open Exchange Management Shell.
- Type the following cmdlet, and then press Enter:
Set-Distributiongroup -identity "Distribution group name" -RequireSenderAuthenticationEnabled $false