Here are the basic steps for connecting IP Gateways or IP PBXs to a Unified Messaging server:

Step 1: Install the Unified Messaging server role

Step 2: Create and configure a UM IP gateway

Step 3: Create a new UM hunt group (possibly)

See the following sections for information about each step.

If you're installing the Unified Messaging server role on an Exchange 2010 server that is separate from the server on which the Mailbox and Hub Transport server roles are installed, use Setup.exe. If you're installing the Unified Messaging server role on the Exchange 2010 computer that currently has the Mailbox and Hub Transport server roles installed, you can use Add or Remove Programs or Setup.com.

For detailed steps, see Install the Exchange 2010 Unified Messaging Server Role.

When you create a UM IP gateway, you can configure the UM IP gateway object to use an IP address or a fully qualified domain name (FQDN). If you use an FQDN, you must make sure you've correctly configured a DNS host record for the IP gateway so the host name will be correctly resolved to an IP address.

A Unified Messaging server will communicate only with IP gateways or IP PBXs listed as a trusted Session Initiation Protocol (SIP) peer. In some cases, if two IP gateways are configured to use the same IP address, an event with ID 1175 will be logged. Unified Messaging protects against unauthorized requests by retrieving the internal URL of the Unified Messaging Web Services virtual directory that is located on the server that has the Client Access role installed and then uses the URL to build the list of FQDNs for the trusted SIP peers. When two FQDNs are resolved to the same IP address, this event will be logged.

Note:

You must restart the Microsoft Exchange Unified Messaging service if an IP gateway is configured to use an FQDN and the IP gateway's DNS record is changed after the service has been started. If you don't restart the service, the UM server won't be able to locate the IP gateway. This occurs because a UM server maintains a cache for all IP gateways in memory and DNS resolution is performed only when the service is restarted or when an IP gateway's configuration has changed.

After you install the IP gateway, you must create a UM IP gateway to represent the IP gateway. After you've created a UM IP gateway object, the UM server associated with the UM IP gateway will send a SIP OPTIONS request to the IP gateway to ensure that the IP gateway is responsive. If the IP gateway doesn't respond to the SIP OPTIONS request from the Unified Messaging server, the Unified Messaging server will log an event with ID 1088 stating that the request failed. To resolve this issue, make sure that the IP gateway is available and online and that the Unified Messaging configuration is correct.

Unified Messaging supports various IP gateway vendors and other vendors of IP PBXs. Each IP gateway is designed to connect to a variety of third-party PBX systems.

For detailed information about IP gateways, see the following topics:

• Create a UM IP Gateway
  
  
• View or Configure the Properties of a UM IP Gateway
  
  
• Configure an IP Gateway or IP PBX for Use with a Unified Messaging Server
  
  

Looking for other management tasks related to Unified Messaging? Check out Managing Unified Messaging Components.

Depending on how you create the UM IP gateway, you may have to create a new UM hunt group. For more information about how to create a UM hunt group, see Create a UM Hunt Group.

After you've connected the UM server to an IP gateway or IP PBX, you may also want to:

• Configure an IP Gateway or IP PBX for Use with a Unified Messaging Server
  
  
• Configure an IP Gateway to Communicate with a PBX