服务器端代码server:

Socket sock = new Socket(AddressFamily.InterNetwork, SocketType.Dgram,ProtocolType.Udp); 
IPEndPoint iep1 = new IPEndPoint(IPAddress.Broadcast, 9050);//255.255.255.255 
IPEndPoint iep2 = new IPEndPoint(IPAddress.Parse("192.168.1.255"), 9050); 
string hostname = Dns.GetHostName(); 
byte[] data = Encoding.ASCII.GetBytes(hostname); 
sock.SetSocketOption(SocketOptionLevel.Socket,SocketOptionName.Broadcast, 1); 
sock.SendTo(data, iep1); 
sock.SendTo(data, iep2); 
sock.Close(); 

客户端代码client:

Socket sock = new Socket(AddressFamily.InterNetwork,SocketType.Dgram, ProtocolType.Udp); 
IPEndPoint iep = new IPEndPoint(IPAddress.Any, 9050); 
sock.Bind(iep); 
 
EndPoint ep = (EndPoint)iep; 
Console.WriteLine("Ready to receive…"); 
byte[] data = new byte[1024]; 
 
int recv = sock.ReceiveFrom(data, ref ep); 
string stringData = Encoding.ASCII.GetString(data, 0, recv); 
Console.WriteLine("received: {0} from: {1}", 
stringData, ep.ToString()); 
data = new byte[1024]; 
 
recv = sock.ReceiveFrom(data, ref ep); 
stringData = Encoding.ASCII.GetString(data, 0, recv); 
Console.WriteLine("received: {0} from: {1}", 
stringData, ep.ToString()); 
 
sock.Close();