Topic Last Modified: 2006-09-06

The Microsoft® Exchange Server Analyzer Tool queries the following attributes for each Routing Group Connector object (msExchRoutingGroupConnector) detected in the Active Directory® directory service to determine whether they have delivery restrictions set based on distribution group membership.

dLMemRejectPerms	Contains the domain names (DNs) of distribution lists (DL) whose members may not send through this Routing Group Connector.
dLMemSubmitPerms	Contains the domain names (DNs) of distribution lists (DL) whose members may send through this Routing Group Connector.

If the Exchange Server Analyzer determines that there are routing group connectors that have delivery restrictions set based on distribution group membership, the Exchange Server Analyzer displays a warning.

This warning indicates that delivery restrictions based on distribution group membership may affect Exchange mail flow performance.

When you send mail by using routing group connectors that have delivery restrictions set based on distribution group membership, the message categorizer must expand the membership of the distribution group, obtain the full list of DNs of the members, and then compare the list of DNs to the list sender’s DNs. An access operation or a deny operation occurs when a DN on both lists match. If a distribution group is nested in another distribution group, the nested distribution is also expanded.

To address this warning:

Design a dedicated routing group for connector restrictions and configure it to a local routing group as referenced in Microsoft Knowledge Base article 329171, "XADM: Mail Delivery Is Slow if Recipients Are Configured with Delivery Restrictions Based on Group Membership" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=329171).
Use a dedicated and more robust global catalog server as the designated bridgehead server for the connector.
Configure individual mailboxes and not distribution groups for delivery restrictions as referenced in Microsoft Knowledge Base article 812298, "Mail delivery is slow after you configure delivery restrictions that are based on a distribution list" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=812298).
Consider implementing Simple Mail Transfer Protocol (SMTP) sender filtering.
For servers that run Exchange Server 2003 Service Pack 2 (SP2) or a later version, consider implementing non-hierarchal restriction checking. For servers that run Exchange versions earlier than Exchange 2003 SP2, consider upgrading to Exchange 2003 SP2.

For More Information

For more information about non-hierarchal restriction checking, see Consider non-hierarchical restriction checking

For more information about SMTP sender filtering, see "How to Enable Sender Filtering" in the Administration Guide for Exchange Server 2003 (http://go.microsoft.com/fwlink/?LinkId=72967).

For more information about the effect of distribution group restriction on Exchange mail flow, see the following Microsoft Knowledge Base articles:

329171 " XADM: Mail Delivery Is Slow if Recipients Are Configured with Delivery Restrictions Based on Group Membership" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=329171).
895407 "In Exchange Server 2003, message delivery to local mailboxes and to external mailboxes is slower than you expect after you configure delivery restrictions based on distribution groups" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=895407).
839949 "Troubleshooting mail transport and distribution groups in Exchange 2000 Server and in Exchange Server 2003" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=839949).