In a mixed Microsoft Exchange Server 2007 Unified Messaging (UM) server and Microsoft Office Communications Server(OCS) 2007 environment, the Auto Attendant is configured for unauthenticated callers to call in.
Dual tone multi-frequency (DTMF) Auto Attendant is only configured to use Key Mapping.
The telephone keys map to extensions and the extensions belong to users who are in the same dial plan as the Auto Attendant.
A public switched telephone network (PSTN) telephone calls Auto Attendant and then selects a key.
Call-id of the PSTN telephone is blocked.
In this scenario, the call transfer fails.
Note A PSTN caller has anonymous caller-id when the caller-id is blocked. A call transfer only works if the caller selects someone from the Activity Directory. Only a call transfer by using key mapping is broken. However, if OCS 2007 is not involved, there is no problem by using key mapping to transfer a call. In other words, a caller with caller-id blocked can perform a call transfer by using key mapping when a call comes to an Exchange Server 2007 UM server directly from a Private Branch Exchange (PBX) device. Additionally, when this problem occurs, the Exchange Server 2007 UM server sets the caller's address as the following: sip: anonymous@<domain name>
The issue that is described in the "Symptoms" section occurs because Exchange Server 2007 UM server does not provide a valid host name for an anonymous call.
To resolve this problem, install the following update rollup:
972076 Description of Update Rollup 2 for Exchange Server 2007 Service Pack 2
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
For more information about DTMF Auto Attendant, visit the following Microsoft Web site: