[DllImport("Iphlpapi.dll")]
private static extern int SendARP(Int32 dest, Int32 host, ref   Int64 mac, ref   Int32 length);
    [DllImport("Ws2_32.dll")]
private static extern Int32 inet_addr(string ip);

///<summary>
///得到客户端ip
///</summary>
///<returns>ip</returns>
        private string GetClientIP()
        {
string result = HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"];
if (null == result || result == String.Empty)
            {
                result = HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"];
            }
if (null == result || result == String.Empty)
            {
                result = HttpContext.Current.Request.UserHostAddress;
            }
return result;
        }


///<summary>
/// 利用客户端ip得到客户端mac
///</summary>
///<param name="remoteip">客户端ip</param>
///<returns>int16类型的mac</returns>
    static private Int64 getremotemac(string remoteip)
    {
        Int32 ldest = inet_addr(remoteip);
try
        {
            Int64 macinfo = new Int64();
            Int32 len = 6;
int res = SendARP(ldest, 0, ref   macinfo, ref   len);
return macinfo;
        }
catch (Exception err)
        {
            Console.WriteLine("error:{0}", err.Message);
        }
return 0;
    }


///<summary>
/// int64类型的mac转换成正确的客户端mac
///</summary>
///<returns>mac</returns>
        private string GetClientMAC()
        {
            Int64 macid = getremotemac(GetClientIP());
if (macid == 0)
return "0";
string beforeMacAddr = Convert.ToString(macid, 16);
string endMacAddr = "";
string[] macArray = new string[6];
for (int i = 0; i < 6; i++)
            {
                macArray[i] = beforeMacAddr.Substring(i * 2, 2);
            }
for (int i = 0; i < 6; i++)
            {
                endMacAddr += macArray[5 - i] + "-";
            }
            endMacAddr = endMacAddr.Substring(0, endMacAddr.Length - 1);
            endMacAddr = endMacAddr.ToUpper();
return endMacAddr;
        }