获取IP及判断IP是否在区间

    /// <summary>
    /// 获取客户端IP
    /// </summary>
    /// <returns></returns>
    public static string GetClientIpAddress()
        {
            var httpContext = HttpContext.Current;
            if (httpContext.Request.ServerVariables == null)
            {
                return null;
            }
 
            var clientIp = httpContext.Request.ServerVariables["HTTP_X_FORWARDED_FOR"] ??
                           httpContext.Request.ServerVariables["REMOTE_ADDR"];
 
            try
            {
                foreach (var hostAddress in Dns.GetHostAddresses(clientIp))
                {
                    if (hostAddress.AddressFamily == AddressFamily.InterNetwork)
                    {
                        return hostAddress.ToString();
                    }
                }
 
                foreach (var hostAddress in Dns.GetHostAddresses(Dns.GetHostName()))
                {
                    if (hostAddress.AddressFamily == AddressFamily.InterNetwork)
                    {
                        return hostAddress.ToString();
                    }
                }
            }
            catch (Exception ex)
            {
 
            }
 
            return clientIp;
        }
 
    /// <summary>
    /// ip是否在ip空间内
    /// </summary>
    /// <param name="ip"></param>
    /// <param name="ipSection"></param>
    /// <returns></returns>
    public static Boolean ipExistsInRange(String ip, String ipSection)
    {
 
        ipSection = ipSection.Trim();
 
        ip = ip.Trim();
 
        int idx = ipSection.IndexOf('-');
 
        String beginIP = ipSection.Substring(, idx);
 
        String endIP = ipSection.Substring(idx + );
 
        return getIp2long(beginIP) <= getIp2long(ip) && getIp2long(ip) <= getIp2long(endIP);
 
    }
 
    public static long getIp2long(String ip)
    {
 
        ip = ip.Trim();
 
        String[] ips = ip.Split('.');
 
        long ip2long = 0L;
 
        for (int i = ; i < ; ++i)
        {
 
            ip2long = ip2long <<  | Int64.Parse(ips[i]);
 
        }
 
        return ip2long;
    }
 
    public static long getIp2long2(String ip)
    {
 
        ip = ip.Trim();
 
        String[] ips = ip.Split('.');
 
        long ip1 = Int64.Parse(ips[]);
 
        long ip2 = Int64.Parse(ips[]);
 
        long ip3 = Int64.Parse(ips[]);
 
        long ip4 = Int64.Parse(ips[]);
 
        long ip2long = 1L * ip1 *  *  *  + ip2 *  *  + ip3 *  + ip4;
 
        return ip2long;
 
    }