关于怎么获取网吧IP的有关问题

关于如何获取网吧IP的问题。
我写了个小东东，帮助捕获指定网卡的数据传输。我在家里和公司的机子上装了都能用。可是有朋友拿到网吧用，就不能用了。是不是网吧的机子有什么特殊的设置？
如果是动态分配，但也应该可以检测出来嘛。有一家网吧显示IP为：0.0.0.61 ，但一点开始绑定，就弹出 "在其上下文中，请求的地址无效"的错误提示。
哪位大侠能帮助解释一下。如何解决这个问题。谢谢。
代码如下：
获取IP列表：
  IPHostEntry HosyEntry = Dns.GetHostEntry((Dns.GetHostName()));
  if (HosyEntry.AddressList.Length > 0)
  {
  int i = 1;
  foreach (IPAddress ip in HosyEntry.AddressList)
  {
  sIPList.Add(ip.ToString());
   
  this.cbox_IP.Items.Add(ip.ToString());
  i++;
  }
  }

绑定IP：
  if (!bContinueCapturing)
  {
  //Start capturing the packets...
  //btnStart.Text = "&Stop";

  bContinueCapturing = true;

  //For sniffing the socket to capture the packets has to be a raw socket, with the
  //address family being of type internetwork, and protocol being IP
  mainSocket = new Socket(AddressFamily.InterNetwork,
  SocketType.Raw, ProtocolType.IP);

  //Bind the socket to the selected IP address
  mainSocket.Bind(new IPEndPoint(IPAddress.Parse(CaptureIPAddress), 0));

  //Set the socket options
  mainSocket.SetSocketOption(SocketOptionLevel.IP, //Applies only to IP packets
  SocketOptionName.HeaderIncluded, //Set the include the header
  true); //option to true

  byte[] byTrue = new byte[4] { 1, 0, 0, 0 };
  byte[] byOut = new byte[4] { 1, 0, 0, 0 }; //Capture outgoing packets

  //Socket.IOControl is analogous to the WSAIoctl method of Winsock 2
  mainSocket.IOControl(IOControlCode.ReceiveAll, //Equivalent to SIO_RCVALL constant of Winsock 2
  byTrue,
  byOut);

  //Start receiving the packets asynchronously
  mainSocket.BeginReceive(byteData, 0, byteData.Length, SocketFlags.None,
  new AsyncCallback(OnReceive), null);
  }
  }
  catch (Exception ex)
  {
  MessageBox.Show(ex.Message, "小工具", MessageBoxButtons.OK, MessageBoxIcon.Error);
  }

[解决办法]
网吧一般都装了网管软件,应该和这个有一点关系.
[解决办法]
网管软件真有可能有关系
[解决办法]
要穿过网吧的“防火墙”
[解决办法]
看看NAT网络穿透技术，哈哈
[解决办法]