Streaming media filter
The streaming media filter allows Firewall and secure network address translation (SecureNAT) clients to use the following streaming media protocols to access media streaming servers such as Microsoft Windows Media Technology (WMT) Server.
| • | Microsoft Windows Media (MMS), which allows Windows Media Player client access and server publishing |
| • | Progressive Networks protocol (PNM), which allows RealPlayer client access and server publishing |
| • | Real Time Streaming Protocol (RTSP), which allows RealPlayer G2 and QuickTime 4 client access and server publishing |
Making media streaming content available to internal users
The streaming media filter can enhance perceived network performance by splitting live streams. Live stream splitting refers to the ability of filters to obtain information from the Internet once, then make it available locally on a Windows Media Technology server for access by other clients.
If you make live stream splitting available, then you can select from the following options:
| • | A single WMT server can retransmit the data. The WMT server must reside on the same computer as ISA Server. |
| • | If an array of ISA Server computers connect your network to the Internet, then you can specify a pool of one or more WMT servers. When a client requests streaming media, then the ISA Server array will obtain the data from the WMT servers. |
In order to use live stream splitting, you must first install the optional Windows Media Services in Windows. If you use the WMT server pool option, then you only need to install the Windows Media Service admin.
You cannot use the local WMT Server and publish WMT server on the ISA Server computer.
For more information, see Configure live stream splitting for media streaming application filter.
Securing access to the internal WMT server
When you use an internal WMT server to make the content available to internal clients, ensure that only clients who have permission in the access policy rules can access the content, even when it is on the WMT server in the internal network. To secure access, you should make the ISA Server a client of the WMT server—no other internal clients should be WMT Server clients.
Media server publishing
Similarly, the streaming media filter can protect an internal streaming media server, which allows external clients to obtain information from the server by way of the ISA Server computer.
Protocol definitions
The streaming media filter uses the following protocol definitions, which are installed with the filter when ISA Server is installed:
| • | Client PNM: RealNetworks protocol |
| • | Server PNM: RealNetworks protocol |
| • | Client RTSP |
| • | Client MMS: Windows Media |
| • | Server MMS: Windows Media |
| • | Server RTSP |
For more information, see Configuring protocol definitions.
You can create protocol rules that limit access to the protocol definitions. For example, you might want to limit client's access to Windows media only You can create a protocol rule that allows the Client MMS: Windows media protocol and another protocol rule that denies use of the Client PNM: RealNetworks protocol. For more information, see Create a protocol rule.
If you disable the streaming media filter, all its protocol definitions are also disabled. That is, traffic that uses Windows Media Technologies, RealNetworks, and RTSP protocol definitions is blocked.