tcp/ip packet listener

You should look at using the UDP protocol instead of TCP/IP.

http://en.wikipedia.org/wiki/User_Datagram_Protocol

Here is the code for the client:

using System.Net;
using System.Net.Sockets;

...

/// <summary>
/// Sends a sepcified number of UDP packets to a host or IP Address.
/// </summary>
/// <param name="hostNameOrAddress">The host name or an IP Address to which the UDP packets will be sent.</param>
/// <param name="destinationPort">The destination port to which the UDP packets will be sent.</param>
/// <param name="data">The data to send in the UDP packet.</param>
/// <param name="count">The number of UDP packets to send.</param>
public static void SendUDPPacket(string hostNameOrAddress, int destinationPort, string data, int count)
{
    // Validate the destination port number
    if (destinationPort < 1 || destinationPort > 65535)
        throw new ArgumentOutOfRangeException("destinationPort", "Parameter destinationPort must be between 1 and 65,535.");

    // Resolve the host name to an IP Address
    IPAddress[] ipAddresses = Dns.GetHostAddresses(hostNameOrAddress);
    if (ipAddresses.Length == 0)
        throw new ArgumentException("Host name or address could not be resolved.", "hostNameOrAddress");

    // Use the first IP Address in the list
    IPAddress destination = ipAddresses[0];            
    IPEndPoint endPoint = new IPEndPoint(destination, destinationPort);
    byte[] buffer = Encoding.ASCII.GetBytes(data);

    // Send the packets
    Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);           
    for(int i = 0; i < count; i++)
        socket.SendTo(buffer, endPoint);
    socket.Close();            
}