This event occurs if you install Exchange 2007 with only the mailbox role enabled, or if you install Exchange 2007 with the hub transport role. You do not select an Exchange 2003 or an Exchange 2000 routing group connector bridge head server. Therefore, there is no routing group connector between the default routing groups in Exchange 2007 and Exchange 2000 or between the default routing groups in Exchange 2007 and Exchange 2003. See ME939764
for information on solving this problem.
On seeing this warning, we tried to troubleshoot SRS issues as suggested by Charlie Chen. However, in our case, it was no help (we had no other error or warnings in the event logs). We called Microsoft and discovered that the Symantec AV client was the culprit. We unchecked “Internet Email Protect” for the AV client. In addition, we excluded the \exchsrvr and \windows\system32\inetsrv folders from the file system scan. All was well after that.
You are mostly likely in a mixed Exchange 5.5/2003 environment. Check the server that is your master router, and also the server on which your SRS service resides. Make sure that the server is up, and that the SRS service is running.
Site Replication Service (SRS) is a component that exchanges configuration information between Active Directory and the directory in Exchange 5.5. In Exchange 5.5, SRS is necessary because Exchange 5.5 configuration information can only be exchanged between Exchange 5.5 servers and Exchange 5.5 directories, not with Active Directory. SRS mimics an Exchange 5.5 directory so that other Exchange 5.5 servers can replicate information to it. Using the configuration connection agreement created by Exchange Setup, Active Directory Connector replicates the configuration information in SRS into Active Directory.
SRS runs only in a mixed-mode Exchange administrative group. SRS also performs additional functions, such as detecting and reacting to directory replication topology changes. You cannot switch from mixed mode to native mode until you have removed all instances of SRS.
SRS is enabled automatically in two situations:
• On the first Exchange 2003 server you install in an Exchange 5.5 organization.
• When you upgrade to Exchange 2000 from an Exchange 5.5 server that is the directory replication bridgehead server for an organization.
When I changed some bridgeheads in my Exchange mailflow, other Exchange servers were unable to reach the other side until AD-replication has occurred, and the SMTP-server has been stopped and started.