通过代理服务器获取真实ip by zhouwillpower

/// 取得客户端真实IP。如果有代理则取第一个非内网地址
/// </summary>
public static string IPAddress
{
    get
    {
        string result = String.Empty; 
        result = HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"];
        if(result!=null&&result!= String.Empty)
        {
            //可能有代理
            if(result.IndexOf(".")==-1)    //没有“.”肯定是非IPv4格式
                result = null;
            else
            {
                if(result.IndexOf(",")!=-1)
                {
                    //有“,”，估计多个代理。取第一个不是内网的IP。
                    result = result.Replace(" ","").Replace("'","");
                    string[] temparyip = result.Split(",;".ToCharArray());
                    for(int i=0;i<temparyip.Length;i++)
                    {
                        if( Text.IsIPAddress(temparyip[i])
                            && temparyip[i].Substring(0,3)!="10."
                            && temparyip[i].Substring(0,7)!="192.168"
                            && temparyip[i].Substring(0,7)!="172.16.")
                        {
                            return temparyip[i];    //找到不是内网的地址
                        }
                    }
                }
                else if(Text.IsIPAddress(result)) //代理即是IP格式
                    return result;
                else
                    result = null;    //代理中的内容 非IP，取IP
            }
 
        } 
        string IpAddress = (HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"]!=null && HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"] !=String.Empty)?HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"]:HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"];  
 
        if (null == result || result == String.Empty)
            result = HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"];
    
        if (result == null || result == String.Empty)
            result = HttpContext.Current.Request.UserHostAddress; 
         return result;
    }
}
/// 判断是否是IP地址格式 0.0.0.0
/// </summary>
/// <param name="str1">待判断的IP地址</param>
/// <returns>true or false</returns>
public static bool IsIPAddress(string str1)
{
    if(str1==null||str1==string.Empty||str1.Length<7||str1.Length>15) return false;

    string regformat = @"^\d{1,3}[\.]\d{1,3}[\.]\d{1,3}[\.]\d{1,3}$";

    Regex regex = new Regex(regformat,RegexOptions.IgnoreCase );
    return regex.IsMatch(str1);
}