判断真实ip

#region 获取真实ip
/// <summary>
/// 获取真实ip
/// </summary>
/// <returns></returns>
public static string GetRealIP(HttpRequest request)
{
string result = String.Empty;

result = request.ServerVariables["HTTP_X_FORWARDED_FOR"];

//可能有代理
if (!string.IsNullOrEmpty(result))
{
//没有"." 肯定是非IP格式
if (result.IndexOf(".") == -1)
{
result = null;
}
else
{
//有","，估计多个代理。取第一个不是内网的IP。
if (result.IndexOf(",") != -1)
{
result = result.Replace(" ", string.Empty).Replace("\"", string.Empty);

string[] temparyip = result.Split(",;".ToCharArray());

if (temparyip != null && temparyip.Length > 0)
{
for (int i = 0; i < temparyip.Length; i++)
{
//找到不是内网的地址
if (IsIPAddress(temparyip )
&& temparyip .Substring(0, 3) != "10."
&& temparyip .Substring(0, 7) != "192.168"
&& temparyip .Substring(0, 7) != "172.16.")
{
return temparyip ;
}
}
}
}
//代理即是IP格式
else if (IsIPAddress(result))
{
return result;
}
//代理中的内容非IP
else
{
result = null;
}
}
}

if (string.IsNullOrEmpty(result))
{
result = request.ServerVariables["REMOTE_ADDR"];
}

if (string.IsNullOrEmpty(result))
{
result = request.UserHostAddress;
}

return result;
}

public static bool IsIPAddress(string str)
{
if (string.IsNullOrEmpty(str) || str.Length < 7 || str.Length > 15)
return false;

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

Regex regex = new Regex(regformat, RegexOptions.IgnoreCase);

return regex.IsMatch(str);
}
#endregion