How do I check to see if UPnP is turned on for my PC?

Check in Administrative Tools | Services.

If you have a router there is also a setting in there for UPnP.
This has to be turned on if you are using a webcam.

1. Universal Plug and Play (UPnP) is an architecture supporting peer-to-peer Plug and Play functionality for network devices that:

? is designed to simplify device and network service installation and management.

? accomplishes device and service discovery and control through a driver-less, standards-based protocol mechanisms.

? can auto-configure network addressing, announce their presence on a network subnet, and enable the exchange of descriptions device and service descriptions.

? enables the computer to act as a UPnP control point to discover and control devices through a web or application interface.

Note: When UPnP support is installed and a UPnP device is added to a network, the Windows-based computer acts as a control point for that device and notification is provided on the taskbar that a new device is available.

2. UPnP involves five processes of functionality:

a. Discovery - A UPnP device advertises its presence on the network to other devices and control points by using the Simple Service Discovery Protocol (SSDP). A newly added control point uses SSDP to discover UPnP devices on the network. The information exchanged between the device and the control point is limited to discovery messages that provide basic information about the devices and their services, along with a description URL, which can be used to gather additional information about the device.

b. Description - Using the URL provided in the discovery process, a control point receives XML information about the device, such as make, model, and serial number. In addition, the description process can also include a list of embedded devices, embedded services, and URLs used to access device features.

c. Control - Control points use URLs provided during the description process to access additional XML information that describes actions to which the Universal Plug and Play device services respond, along with parameters for each action. Control messages are formatted in XML and use the Simple Object Access Protocol (SOAP) protocol.

d. Eventing - When a control point subscribes to a service, the service sends event messages to the control point to announce changes in device status. Event messages are formatted in XML and use General Event Notification Architecture (GENA).

e. Presentation - If a UPnP device provides a presentation URL, a browser can be used to access interface control features, device or service information, or any device-specific abilities implemented by the manufacturer.

3. To disable UPnP to determine whether the computer still operates or operates better and faster:

a. Right-click My Computer, Manage, Services and Applications, and then select "Services" (click to see an example screenshot).

b. Scroll down and double-click SSDP Dicovery Service, and then click Stop, Startup type, and then select Disabled.

c. Click OK to Exit and restart the computer.

4. Caveats:

a. When a computer is in Standby mode, any UPnP device(s) connected to the computer cannot be detected.

b. The Wake on LAN (WOL, where LAN is the abbreviation for local area network) ability of some network adapters is not activated by UPnP.

5. Supplemental reading:

a. "Microsoft Security Bulletin MS01-059" - Unchecked Buffer in Universal Plug and Play can Lead to System Compromise

b. "How to Add OEM Plug and Play Drivers to Windows Installations (Q25407 - Win2000."

c. "Invalid Universal Plug and Play Request can Disrupt System Operation (Q309073)."

Note: By sending a particular set of commands to an affected computer, an attacker could gradually deplete resources on a system to the point where performance could be slowed, or stopped altogether.

d. "Preventing Distributed Denial-of-Service Attacks that Use the Universal Plug-and-Play Service(Q315056)."

e. "Unchecked Buffer in Universal Plug and Play Can Lead to System Compromise for Windows XP (Q315000)."

f. "Universal Plug and Play in Windows XP."