获取客户机MAC地址 根据IP地址 获取机器的MAC地址 / 获取真实Ip地址

        [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>
        /// 获取客户机MAC地址  根据IP地址 获取机器的MAC地址
        /// </summary>
        /// <returns></returns>
        public static string GetBarMACIP(string strIP)
        {
            //MAC信息
            string mac_dest = "";
            try
            {
                int ldest = inet_addr(strIP); //目的地的ip
                int lhost = inet_addr("");   //本地服务器的ip
                Int64 macinfo = new Int64();
                int len = ;
                int res = SendARP(ldest, , ref macinfo, ref len);
                string mac_src = macinfo.ToString("X");
                if (mac_src == "")
                {
                    return "";
                }
                while (mac_src.Length < )
                {
                    mac_src = mac_src.Insert(, "");
                }

                for (int i = ; i < ; i++)
                {
                    if ( == (i % ))
                    {
                        if (i == )
                        {
                            mac_dest = mac_dest.Insert(, mac_src.Substring(i, ));
                        }
                        else
                        {
                            mac_dest = "-" + mac_dest.Insert(, mac_src.Substring(i, ));
                        }
                    }
                }
                return mac_dest;
            }
            catch
            {
                return "";
            }
        }

        /// <summary>
        /// 取得IP地址
        /// </summary>
        /// <returns></returns>
        public static string GetIp()
        {
            string str = "";
            //穿过代理服务器取远程用户真实IP地址：
            if (System.Web.HttpContext.Current.Request.ServerVariables["HTTP_VIA"] != null)
                str = System.Web.HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"].ToString();
            else
                str = System.Web.HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"].ToString();
            return str;
        }