WORKAROUND
To work around this problem, use one of the following
methods.
Method 1: Limit the Use of this Delivery Restriction
Try to limit the number of servers that use this kind of delivery
restriction. If you can, enable this kind of delivery restriction only on
source bridgehead servers in your organization. If you can limit this to only
certain bridgehead servers, try to dedicate a global catalog (GC) server to
each of these bridgehead servers.
Method 2: Use User-Based Delivery Restrictions
Add the specific user accounts to the
Accept messages
from list instead of using distribution lists. This increases
performance because whereas Exchange Server does not cache the results of
the expanded distribution list, it does cache the results of delivery
restrictions that are based on individual user accounts. This method works when
you want to add up to 1,000 user accounts. However, if you want to accept
messages from more than 1,000 users, create additional SMTP connectors. You
must make sure that each is identically configured, and then add up to 1,000
user accounts to the
Accept messages from box on each connector.
Important Make sure that each SMTP connector is assigned the same cost.
Otherwise, Exchange Server queries only the first SMTP connector, and
returns a non-delivery report (NDR) if the user account is not listed in the
Accept messages from list of that connector.
For more information about another solution that is available if you are running Microsoft Exchange Server 2003 Service Pack 2 or a later verion of Exchange Server 2003, click the following article number to view the article in the Microsoft Knowledge Base:
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