1. Log on to the computer where Topology Builder is installed as a member of the Domain Admins group and the RTCUniversalServerAdmins group.

2. Start Topology Builder: Click Start, click All Programs, click Microsoft Lync Server 2010, and then click Lync Server Topology Builder.

3. In Topology Builder, in the console tree under Standard Edition Front End Servers, Enterprise Edition Front End pools, and Directory pools, select the pool name. Right-click the name, click Edit Properties, and then click Web Services.

4. Add or edit the External Web Services FQDN, and then click OK.

5. Verify the listening and published ports are configured correctly for your environment.

6. Repeat these steps for all Standard Edition servers, Front End Pools, and Director pools in your environment.

7. In the console tree, click Lync Server 2010, and then, in the Actions pane, click Publish Topology.

There are a few requirements you should be aware of when configuring the Listening and Publishing ports:

• The listening ports shown are the ports that are configured for Internet Information Server (IIS) on each Front End Server.
  
  
• The internal and external listening ports must be different for IIS. For the external listening ports, these are typically the same because one represents the hardware load balancer for internal web traffic and one represents the reverse proxy server for external web traffic.
  
  
• The published ports must be configured on the reverse proxy or hardware load balancer as listening ports.
  
  
• For an Front End pool (not shown in the example), the internal SIP pool FQDN must be different from the internal web services FQDN, because web traffic comes through the hardware load balancer and the internal SIP pool traffic travels comes through the DNS load balancer. This requirement must be met.
  
  
• A Lync Server Standard Edition deployment does not need or allow an internal web services FQDN to be overridden because this server cannot be load balanced.
  
  
• If you have a hardware load balancer in your environment that you use for both internal SIP and web traffic, the Topology Builder cannot make the distinction.
  
  

The external web services works in conjunction with a reverse proxy in the perimeter network. It provides clients external access to Microsoft Lync Server 2010 by using these web services. The FQDNs configured here are sent to clients when they log on, and are used to make an HTTPS connection back to the reverse proxy when connecting remotely. The reverse-proxy server forwards the external web service FQDN to an internal hardware load balancer, or directly to the pool. The reverse proxy must be able to resolve the external web services FQDN to the IP address of the internal Web server. The external web services FDQN must be resolvable in the public Internet.

If your internal server is a Standard Edition server, the internal FQDN is the Standard Edition server FQDN. If your internal server is a Front End pool, the FQDN is a hardware load balancer virtual IP (VIP) that load balances the internal web farm servers. A hardware load balancer is required in a Front End pool with more than one Enterprise Edition server. A load balancer is not required for a Standard Edition server or a single Enterprise Edition Front End Server.