About network listeners
You can configure Microsoft Forefront Threat Management Gateway to listen for requests from internal and external clients as follows:
You can create and configure Web listeners to be used in Web publishing rules. Web listeners define an IP address and port on the network used to listen for inbound Web requests. For more information, see Web listener overview.
When you create a server publishing rule to publish a non-Web server, you are actually configuring a Forefront TMG network to listen for requests on behalf of that server. For example, if the published service accepts client requests from the Internet, then you should configure the External network as the network listener. The server publishing rule specifies the protocol that the server publishes and the port number associated with the protocol. For more information, see Overview of non-HTTP server publishing.
You can configure networks to listen for Web proxy requests from internal clients. By default, Forefront TMG networks listen for such requests on port 8080. For more information, see About Web proxy clients.