Purpose & Scope

Inside users can connect to the live communication server using windows messenger client through the Local Network. Also outside users can connect over a virtual private network (VPN) to gain access to a computer running Live Communications Server, a VPN might not be available or practical for some deployments.

An alternative to using VPN, Live Communications Server can be deployed to enable outside users to connect using Transport Layer Security (TLS) securely through ISA Server. When properly configured, users will have access to presence and instant messaging from the public network.

Note:When you use ISA Server2004 with Live Communications Server, only presence and instant messaging will be enabled for outside users. Scenarios involving features such as audio and video, data collaboration, and file transfer are not supported.

You can configure ISA server 2004 as the following:

1. Add a Server Publishing Rule for the Live Communication Server requests
2. Create a protocol definition for the (session initiation protocol) SIPS protocol
   1. In the ISA Server Management console, select Firewall Policy.
   2. In the task pane, select the Toolbox tab, and click Protocols.
   3. Under Protocols, click New, and then click Protocol to open the New Protocol Definition Wizard.
   4. On the New Protocol Definition Wizard Welcome page, in the Protocol definition name box, type SIPS, and then click Next.
   5. On the Primary Connection Information page, click New
   6. In the New/Edit Protocol Connection dialog box, in the Protocol type list, select TCP.
   7. In Direction, select Inbound.
   8. In From and to, type 5061 if you are welling to use certificates, and 5060 if your not.
   9. Click OK to close the New/Edit Protocol Connection dialog box.
   10. On the Primary Connection Information page, click Next.
   11. On the Secondary Connections page, in Do you want to use secondary connections, select No, and then click Next.
   12. Click Finish to close the New Protocol Definition Wizard. Notice that the SIPS protocol definition is listed under the User-Defined folder under the Protocols menu.
3. Create a server publishing rule to allow inbound requests to the Live Communications
   1. In ISA Server Management, select Firewall Policy.
   2. In the task pane, on the Tasks tab, click Create New Server Publishing Rule to open the New Server Publishing Rule Wizard.
   3. On the New Server Publishing Rule Wizard Welcome page, provide a name for the rule, such as Publish SIPS for Live Communications Server, and then click Next.
   4. On the Select Server page, in Server IP address, type the IP address of your computer that is running Live Communications Server, and then click Next.
   5. On the Select Protocol page, from the Selected protocol drop-down list, select the SIPS user-defined protocol, and then click Next.
   6. On the IP Addresses page, under Listen for requests from these networks, select External
      Note: You can select specific IP addresses that ISA Server will listen on. To do this, click the Address button, and then for the selected network, specify the IP addresses that ISA Server will listen on.
   7. Click Next.
   8. Click Finish to close the New Server Publishing Rule Wizard.
      Notice that in the ISA Server Management console, in the details pane, on the Firewall Policy tab, the new rule is listed.
   9. Optional on the Firewall Policy tab, under the Name column, double-click the Publish SIPS for Live Communications Server rule to open its properties. Note: On the To tab, under Requests for the published server, there is an option Requests appear to come from the ISA Server computer. This option can be used when you have not configured ISA Server as the default gateway on the published server. The disadvantage of this approach is that the published server will be unaware of the address of the client, which is a problem for server applications that use the client address for logging or for policy decisions.

In the details pane, click the Apply button to apply the changes you made.

For more information please visit the following link:
http://www.microsoft.com/technet/prodtechnol/isa/2004/plan/tls-isa.mspx

Additional Comments
applies to MLG 2005, ISA 2004, LCS 2003,LCS 2005