获取多级代理时客户端真实IP地址

一、取到客户端IP地址（包括多级代理情况下获取）

        #region 获取 HTTP 请求的客户端 IP 地址(包括多级代理的情况)
        /// <summary>
        /// 获取 HTTP 请求的客户端 IP 地址。
        /// </summary>
        /// <param name="context">HTTP 的执行上下文对象。</param>
        /// <returns>客户端 IP 地址。</returns>
        public static String GetHttpClientIp(HttpContext context)
        {
            String ipAddress = String.Empty;
            if (null != context && null != context.Request)
            {
                String remoteAddr = context.Request.ServerVariables["REMOTE_ADDR"] ?? String.Empty;
                String httpXForwardedFor = context.Request.ServerVariables["HTTP_X_FORWARDED_FOR"] ?? String.Empty;
                remoteAddr = remoteAddr.Trim();
                httpXForwardedFor = httpXForwardedFor.Trim();
                if (!string.IsNullOrEmpty(httpXForwardedFor))
                {                                                   //  存在代理的情况下。
                    if (httpXForwardedFor.IndexOf(".") > 0)
                    {                                               //  判断是否非IP V6（2001:0db8:85a3:08d3:1319:8a2e:0370:7344）。
                        if (httpXForwardedFor.IndexOf(",") > 0)
                        {                                           //  多个代理的情况下。
                            httpXForwardedFor = httpXForwardedFor.Replace(" ", "").Replace("'", "");
                            String[] tempArrayIp = httpXForwardedFor.Split(",;".ToCharArray(), StringSplitOptions.RemoveEmptyEntries);
                            for (int i = 0; i < tempArrayIp.Length; i++)
                            {
                                if (!IsIPV4Innner(tempArrayIp[i]) && IsIPV4(tempArrayIp[i]))
                                {
                                    ipAddress = tempArrayIp[i];
                                }
                            }
                        }
                        else if (!IsIPV4Innner(httpXForwardedFor) && IsIPV4(httpXForwardedFor))
                        {                                           //  单个代理的情况下。
                            ipAddress = httpXForwardedFor;
                        }
                    }
                }
                if (string.IsNullOrEmpty(ipAddress) && IsIPV4(remoteAddr))
                {
                    ipAddress = remoteAddr;
                }
                if (string.IsNullOrEmpty(ipAddress))
                {
                    ipAddress = context.Request.UserHostAddress;
                }
            }
            return ipAddress;
        }
        #endregion

 

二、根据实际业务需要验证是否为自己内网的IP地址（匹配规则根据自己内网IP）.

        #region 判断指定字符串是否是 IP V4 格式的内网 IP
        /// <summary>
        /// 判断指定字符串是否是 IP V4 格式的内网 IP。
        /// </summary>
        /// <param name="ipAddress">表示 IP V4 的字符串。</param>
        /// <returns>
        ///  如果是 IP V4 格式的内网 IP字符串，则返回<c>true</c>；否则，返回<c>false</c>。
        /// </returns>
        public static Boolean IsIPV4Innner(String ipAddress)
        {
            Int64 aBegin = IpAddressToLong("10.0.0.0");
            Int64 aEnd = IpAddressToLong("10.255.255.255");
            Int64 bBegin = IpAddressToLong("172.16.0.0");
            Int64 bEnd = IpAddressToLong("172.31.255.255");
            Int64 cBegin = IpAddressToLong("192.168.0.0");
            Int64 cEnd = IpAddressToLong("192.168.255.255");
            Int64 ip = IpAddressToLong(ipAddress);
            if (IsIPV4(ipAddress) && (                          //  是正确的 IPV4 字符串表达形式。
                (ip >= aBegin && ip <= aEnd) ||                 //  IP 在 10.0.0.0 与 10.255.255.255 之间。
                (ip >= bBegin && ip <= bEnd) ||                 //  IP 在 172.16.0.0 与 172.31.255.255 之间。
                (ip >= cBegin && ip <= cEnd))                   //  IP 在 192.168.0.0 与 192.168.255.255 之间。
                )
            {
                return true;
            }
            return false;
        }
        #endregion

 

三、验证IP串是否为IP V4 格式

        #region 判断指定字符串是否是 IP V4 格式。
        /// <summary>
        /// 判断指定字符串是否是 IP V4 格式。
        /// </summary>
        /// <param name="ipAddress">表示 IP V4 的字符串。</param>
        /// <returns>
        ///  如果是 IP V4 格式的字符串，则返回<c>true</c>；否则，返回<c>false</c>。
        /// </returns>
        public static Boolean IsIPV4(String ipAddress)
        {
            Regex regex = new Regex(@"(((\d{1,2})|(1\d{2})|(2[0-4]\d)|(25[0-5]))\.){3}((\d{1,2})|(1\d{2})|(2[0-4]\d)|(25[0-5]))");
            return !string.IsNullOrEmpty(ipAddress) && regex.IsMatch(ipAddress);
        }
        #endregion