This documentation is archived and is not being maintained.

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 */
public boolean get_MulticastLoopback ()

/** @property */
public void set_MulticastLoopback (boolean value)

public function get MulticastLoopback () : boolean

public function set MulticastLoopback (value : boolean)

Not applicable.

Property Value

true if the Socket receives outgoing multicast packets; otherwise, false.

Exception typeCondition


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}", 

Windows 98, Windows Server 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0