This TechNet Wiki page explains how the new UDP based push notification feature introduced with
Update Rollup 3-v3
for Exchange 2010 SP1 works. In addition, it explains how you configure a static UDP port and what you need to consider before enabling this feature.
For information on how to configure static RPC ports on an Exchange 2010 Client Access Server, the
Configuring Static RPC Ports on an Exchange 2010 Client Access Server TechNet Wiki article.
Up until Exchange Server 2010 SP1 Update Rollup 2, Exchange 2010 didn’t have support for User Datagram Protocol (UDP) notifications. When opening a mailbox using Outlook 2003, Outlook
2003 tries to register itself to receive new message notifications. However since this notification method wasn’t supported with Exchange 2010, Outlook 2003 instead reverted to polling the Exchange server for changes in the mailbox. Despite the fact that Outlook
2003 initiates the polling behavior, the Exchange server will dictate the polling frequency. By default Outlook 2003 polls the Exchange server every 60 seconds.
Because of this, the end users would see the following symptoms:
There were two methods that could be used to work around the above symptoms:
Based on customer feedback, the Exchange product group decided to re-add support for UDP notifications in Exchange 2010. This means that when
Update Rollup 3-v3
has been applied on Exchange 2010 SP1 Client Access Servers, you now have a third workaround:
Update Rollup 3-v3
has been applied to the Exchange 2010 SP1 Client Access Servers in the organization, push notifications can be enabled by creating a new DWORD registry key named “EnablePushNotifications” under the following location:
The value for the key should be set to “1” in order to enable push notifications.
In this example the source RPC port used on the CAS server is port 49517 and the destination RPC port on the machine on which Outlook 2003 is running is port 1211.
By default Windows Server 2008 and 2008 R2 are configured with a dynamic RPC range of 49152-65535 for outbound connections. Earlier versions of Windows Server
by default used port 1025-65535 (for more details about this change see Microsoft KB article:
The default dynamic port range for TCP/IP has changed in Windows Vista and in Windows Server 2008). Also, when the Exchange 2010 Client Access server role is installed on Windows Server 2008
or 2008 R2, the dynamic RPC port range is changed to 6005-59530 and the highest usable port number is set to 60554.
If you have configured a static RPC port for the
RPC Client Access (RPC CA) service, Exchange Address Book (AB) service, and for public folder (PF) connections on the Exchange 2010 Client Access Servers within
the organization, you might wonder how you configure a static port for UDP notifications. Well, since this is all about push notifications (notifications pushed to the Outlook 2003 client), you cannot configure a static UDP port on the CAS servers. From the
CAS server perspective, we will always see a random source port within the dynamic RPC range being used. However, you can configure a static UDP port on the client side. More specifically you can configure an Outlook 2003 specific registry key that forces
CAS servers to use a static RPC destination port for push notifications.
To set static UDP port on a client machine, you need to create a DWORD registry key named “FixedUDPPort” under the following location:
The value for this key should be set to the RPC port you wish to use.
After having configured the static UDP port, you will need to restart the Outlook 2003 client.
If we use port 59534 as the static port, we can see this being reflected in NetMon as shown below.
When using a client access array and a load balancer solution to distribute client traffic across the Exchange 2010 CAS servers in the CAS array, you don't need
to create a UDP specific rule or virtual service on the load balancer solution. This is because push notifications are sent from the CAS server(s) to the Outlook 2003 client. UDP notifications do not occur from the Outlook 2003 client to the CAS server(s).
You must open the static UDP port (in this case port 59534) you decide to use for push notifications in any firewall that is placed between the Exchange 2010 CAS
servers and the client machines.