public static void disconnect8300()
        {
            List <TcpProcessRecord> tcpClientList = GetAllTcpConnections();

            foreach (TcpProcessRecord tcpRecord in tcpClientList)
            {
                if (tcpRecord.RemotePort == 8300)
                {
                    MIB_TCPROW connToDelete = new MIB_TCPROW();
                    connToDelete.state      = MibTcpState.DELETE_TCB;
                    connToDelete.localAddr  = (int)tcpRecord.LocalAddress.Address;
                    connToDelete.localPort  = htons(tcpRecord.LocalPort);
                    connToDelete.remoteAddr = (int)tcpRecord.RemoteAddress.Address;
                    connToDelete.remotePort = htons(tcpRecord.RemotePort);
                    IntPtr tcprowPtr = GetPtrFromTCPROW(connToDelete);
                    int    ret       = SetTcpEntry(tcprowPtr);
                    ReleasePtrForTCPROW(tcprowPtr);
                    if (ret != 0)
                    {
                        uint          dwFlags  = FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS;
                        StringBuilder lpBuffer = new StringBuilder(260);    //声明StringBuilder的初始大小
                        int           count    = FormatMessage(dwFlags, IntPtr.Zero, 1439, 0, lpBuffer, 260, IntPtr.Zero);
                        Console.WriteLine("disconnect fail, ret = " + ret + " info:" + lpBuffer.ToString());
                    }
                    //Console.WriteLine(String.Format("localaddr:{0},localport:{1},remoteaddr:{2},remoteport:{3}",
                    //    connToDelete.localAddr, connToDelete.localPort, connToDelete.remoteAddr, connToDelete.remotePort));

                    break;
                }
            }
        }
        private static IntPtr GetPtrFromTCPROW(MIB_TCPROW obj)
        {
            IntPtr ptr = Marshal.AllocCoTaskMem(Marshal.SizeOf(obj));

            Marshal.StructureToPtr(obj, ptr, false);
            return(ptr);
        }
        //The function that fills the MIB_TCPROW array with connectioninfos
        private static MIB_TCPROW[] getTcpTable()
        {
            IntPtr buffer = IntPtr.Zero; bool allocated = false;

            try
            {
                int iBytes = 0;
                GetTcpTable(IntPtr.Zero, ref iBytes, false); //Getting size of return data
                buffer = Marshal.AllocCoTaskMem(iBytes);     //allocating the datasize

                allocated = true;

                GetTcpTable(buffer, ref iBytes, false);             //Run it again to fill the memory with the data

                int structCount = Marshal.ReadInt32(buffer);        // Get the number of structures

                IntPtr buffSubPointer = buffer;                     //Making a pointer that will point into the buffer
                buffSubPointer = (IntPtr)((int)buffer + 4);         //Move to the first data (ignoring dwNumEntries from the original MIB_TCPTABLE struct)

                MIB_TCPROW[] tcpRows = new MIB_TCPROW[structCount]; //Declaring the array

                //Get the struct size
                MIB_TCPROW tmp          = new MIB_TCPROW();
                int        sizeOfTCPROW = Marshal.SizeOf(tmp);

                //Fill the array 1 by 1
                for (int i = 0; i < structCount; i++)
                {
                    tcpRows[i]     = (MIB_TCPROW)Marshal.PtrToStructure(buffSubPointer, typeof(MIB_TCPROW)); //copy struct data
                    buffSubPointer = (IntPtr)((int)buffSubPointer + sizeOfTCPROW);                           //move to next structdata
                }

                return(tcpRows);
            }
            catch (Exception ex)
            {
                throw new Exception("getTcpTable failed! [" + ex.GetType().ToString() + "," + ex.Message + "]");
            }
            finally
            {
                if (allocated)
                {
                    Marshal.FreeCoTaskMem(buffer);            //Free the allocated memory
                }
            }
        }
 public static void CloseRemotePort(int port)
 {
     MIB_TCPROW[] rows = getTcpTable();
     for (int i = 0; i < rows.Length; i++)
     {
         if (port == ntohs(rows[i].remotePort))
         {
             MIB_TCPROW tcpRecord = rows[i];
             tcpRecord.state = MibTcpState.DELETE_TCB;
             IntPtr ptr = GetPtrFromTCPROW(tcpRecord);
             //Console.WriteLine(String.Format("localaddr:{0},localport:{1},remoteaddr:{2},remoteport:{3}",
             //    tcpRecord.localAddr, tcpRecord.localPort, tcpRecord.remoteAddr, tcpRecord.remotePort));
             int ret = SetTcpEntry(ptr);
             ReleasePtrForTCPROW(ptr);
             if (ret != 0)
             {
                 uint          dwFlags  = FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS;
                 StringBuilder lpBuffer = new StringBuilder(260);    //声明StringBuilder的初始大小
                 int           count    = FormatMessage(dwFlags, IntPtr.Zero, 1439, 0, lpBuffer, 260, IntPtr.Zero);
                 Console.WriteLine("disconnect fail, ret = " + ret + " info:" + lpBuffer.ToString());
             }
         }
     }
 }