Broadcasting is frequently used in local area networks. If you want to send a message to all local computers you can use broadcasts. Here we will discuss about broadcasting  on TCP/IP network protocol. For example if you want to find a resource on network you can send a broadcast to all computers. Then computer(s) that  contain that resource can answer to you. You can find several applications for broadcasting. Just be sure to use broadcasting whenever it is really needed.  To send broadcasts you use UDP protocol to send packets to IP address 255.255.255.255 and you can choose any port that is  free on your computers. Sending and receiving UDP broadcasts is very easy. You will  not need a connect session for UDP. You just send and receive packets. Also packet size limitation is related to your  network devices but assume 256 bytes for maximum size of data you send each time. Below you see a sample program written in Visual Basic using MSWinsock.ocx component. This component is the most stable socket object I have seen until now. It is very easy to program sockets with this object. I even prefer this object to native Delphi  and C++Builder socket objects (Borland, Net Master and Indy)  in that environments.     Private Sub Command1_Click()     On Local Error Resume Next     Dim str As Variant     str = CVar(Text1.Text)     Winsock1.RemoteHost = "255.255.255.255"     Winsock1.RemotePort = 20480     Winsock1.SendData str    End Sub    Private Sub Form_Load()      Winsock1.Bind 20480    End Sub    Private Sub Form_Unload(Cancel As Integer)      Winsock1.Close    End Sub    Private Sub Winsock1_DataArrival(ByVal bytesTotal As Long)      Winsock1.GetData str, vbString      Text2.Text = str    End Sub Form contains a command button and two text boxes. If you want to write in other environment there is a Broadcast Page at this address:    http://www.angelfire.com/nt/sarmadys/page3.html