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Socket.MulticastLoopback Property

Gets or sets a value that specifies whether outgoing multicast packets are delivered to the sending application.

Namespace:  System.Net.Sockets
Assembly:  System (in System.dll)

public bool MulticastLoopback { get; set; }

Property Value

Type: System.Boolean
true if the Socket receives outgoing multicast packets; otherwise, false.


An error occurred when attempting to access the socket.


The Socket has been closed.

Multicast is a scalable method for many-to-many communication on the Internet. A process subscribes to a multicast address; then, any packets sent by a subscribed process are received by every other process subscribed to the multicast address.

Setting this property on a Transmission Control Protocol (TCP) socket will have no effect.

The following code example demonstrates the use of the MulticastLoopback property.

        static void ConfigureUdpSocket(Socket udpSocket)
			// set the Don't Fragment flag.
			udpSocket.DontFragment = true;
			// Enable broadcast.
			udpSocket.EnableBroadcast = true;

			// Disable multicast loopback.
			udpSocket.MulticastLoopback = false;

			Console.WriteLine("Udp Socket configured:");
			Console.WriteLine("  DontFragment {0}", 
			Console.WriteLine("  EnableBroadcast {0}", 
			Console.WriteLine("  MulticastLoopback {0}", 

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.