Asp.net MVC获取访问系统的客户端计算机的主机名和IP地址

string HostName = string.Empty;
string ip = string.Empty;
string ipv4 = String.Empty;

if (!string.IsNullOrEmpty(System.Web.HttpContext.Current.Request.ServerVariables["HTTP_VIA"]))
ip = Convert.ToString(System.Web.HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"]);
if (string.IsNullOrEmpty(ip))
ip = Request.UserHostAddress;

// 利用 Dns.GetHostEntry 方法，由获取的 IPv6 位址反查 DNS 纪录，
// 再逐一判断何者为 IPv4 协议，即可转为 IPv4 位址。
foreach (IPAddress ipAddr in Dns.GetHostEntry(ip).AddressList)
{
if (ipAddr.AddressFamily.ToString() == "InterNetwork")
{
ipv4 = ipAddr.ToString();
}
}

HostName = "主机名: " + Dns.GetHostEntry(ip).HostName + " IP: " + ipv4;

　　在本机进行程序代码调试测试，其中字符串ip会显示为::1，是IPv6的IP地址格式，相当于127.0.0.1。最终处理成IPv4的显示地址。

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上述方法，代码调试没有问题，但是放在服务器上后，客户端访问就出问题了，有部分电脑能获取主机名，但是ipv4显示为空，另外一部分

Dns.GetHostEntry(ip)中的ip正常，但是执行Dns.GetHostEntry(ip)貌似为null，导致出现异常。最后选择的方法是只记录客户端的IPV4，

/// <summary>
/// 获取web客户端ip
/// </summary>
/// <returns></returns>
public static string GetWebClientIp()
{

string userIP = "未获取用户IP";

try
{
if (System.Web.HttpContext.Current == null
|| System.Web.HttpContext.Current.Request == null
|| System.Web.HttpContext.Current.Request.ServerVariables == null)
{
return "";
}

string CustomerIP = "";

//CDN加速后取到的IP simone 090805
CustomerIP = System.Web.HttpContext.Current.Request.Headers["Cdn-Src-Ip"];
if (!string.IsNullOrEmpty(CustomerIP))
{
return CustomerIP;
}

CustomerIP = System.Web.HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"];

if (!String.IsNullOrEmpty(CustomerIP))
{
return CustomerIP;
}

if (System.Web.HttpContext.Current.Request.ServerVariables["HTTP_VIA"] != null)
{
CustomerIP = System.Web.HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"];

if (CustomerIP == null)
{
CustomerIP = System.Web.HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"];
}
}
else
{
CustomerIP = System.Web.HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"];
}

if (string.Compare(CustomerIP, "unknown", true) == 0 || String.IsNullOrEmpty(CustomerIP))
{
return System.Web.HttpContext.Current.Request.UserHostAddress;
}
return CustomerIP;
}
catch { }

return userIP;

}