asp.net - 获取用户的IP地址

Question

如何获得当前访问者的IP地址？

Answer 1

编辑:还发现了一个有趣的问题，涉及与IP相关的HTTP header here。

Edit2:如评论和上面提供的链接中所述，HTTP_X_FORWARDED_FOR header 可能包含多个IP地址，以逗号分隔。我没有遇到这种情况，但是认为需要对我的答案进行一些更正。

我使用以下代码来获取IP地址(如果由于某种原因而失败，它将返回IPAddress.None值):

    /// <summary>
    /// Gets the IP address of the request.
    /// <remarks>
    /// This method is more useful than built in because in some cases it may show real user IP address even under proxy.
    /// <summary>
    /// Gets the IP address of the request.
    /// <remarks>
    /// This method is more useful than built in because in some cases it may show real user IP address even under proxy.
    /// The <see cref="System.Net.IPAddress.None" /> value will be returned if getting is failed.
    /// </remarks>
    /// </summary>
    /// <param name="request">The HTTP request object.</param>
    /// <returns></returns>
    public static IPAddress GetIp(this HttpRequest request)
    {
        string ipString;
        if (string.IsNullOrEmpty(request.ServerVariables["HTTP_X_FORWARDED_FOR"]))
        {
            ipString = request.ServerVariables["REMOTE_ADDR"];
        }
        else
        {
            ipString = request.ServerVariables["HTTP_X_FORWARDED_FOR"].Split(",".ToCharArray(), StringSplitOptions.RemoveEmptyEntries)
                .FirstOrDefault();
        }

        IPAddress result;
        if (!IPAddress.TryParse(ipString, out result))
        {
            result = IPAddress.None;
        }

        return result;
    }