How to Configure Internal NetMeeting Clients to Call External Netmeeting Clients

This article describes how to configure internal Microsoft Netmeeting client computers to call external NetMeeting clients by using the H.323 Gatekeeper service in Internet Security and Acceleration (ISA) Server.

For internal Netmeeting clients to be able to call external clients, they must place a call based on the Internet protocol (IP) address or the fully qualified domain name (FQDN) of the external client. For this call to be successful, you must configure IP rules in Gatekeeper to distinguish between internal and external IP addresses. By default, Gatekeeper is configured to assume that all IP networks are internal. To configure Gatekeeper to distinguish between internal and external IP addresses:

1. Click to expand H.323 Gatekeeper.
2. Click to expand Server Name.
3. Click to expand Call Routing.
4. Click IP address rules.
   
   In the right pane, three default rules for Classes A, B and C IP address ranges are displayed. If all of these IP ranges are external, you must reconfigure these rules to use a gateway or proxy-type destination before you proceed. To do so:
   1. Click to expand H.323 Gatekeeper.
   2. Click to expand Server Name.
   3. Click to expand Call Routing.
   4. Right-click Destinations, and then click Add Destination.
   5. When the New Destination Wizard starts, click Next, and then perform the following steps:
      • On the Destination Type page, click Gateway or Proxy Server, and then click Next.
      • On the Destination Name or Address Page, type the internal IP of the ISA Server, and then click Next.
      • On the Destination Description page, type Local ISA Server, click Next, and then click Finish.

In the Netmeeting client, when you place a call based on the IP address, Gatekeeper now forwards that call to the Internet. If you use an FQDN, the call takes slightly longer to connect because of DNS resolution of the FQDN.

Netmeeting clients are not required to use Gatekeeper if they do not want to be reached by other internal users through the directory. However, if clients that are external to ISA Server want to contact internal Netmeeting clients, the internal Netmeeting clients must register with ISA Server as the gatekeeper by using a phone number (do not enter spaces or hyphens). To use ISA Server to authenticate outbound calls if the user is not logged on to the domain, and if the firewall client is not installed on the client, set this rule to use client sets that include the client's IP address; you can also configure this rule to Any Request, so that it applies to all requests.

For more information about how to create and use Protocol rules, refer to the Online Help in ISA Server.