客户端IP返回::1的解决办法

刚刚测试程序，一个功能要求获取客户端IP，然而在本机测试过程中发现，客户端(本机)IP始终返回::1，获取 IP 部份的代码如下：

Code

private string GetIP()

{

string result = String.Empty;

result = HttpContext.Current.Request.ServerVariables["HTTP_X_FORWARDED_FOR"];

if (null == result || result == String.Empty)

{

result = HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"];

}

if (null == result || result == String.Empty)

{

result = HttpContext.Current.Request.UserHostAddress;

}

if (null == result || result == String.Empty || !IsIP(result))

{

result = "0.0.0.0";

}

return result;

}

public static bool IsIP(string ip)

{

return Regex.IsMatch(ip, @"^((2[0-4]\d|25[0-5]|[01]?\d\d?)\.){3}(2[0-4]\d|25[0-5]|[01]?\d\d?)$");

}

于是最终获取倒的是因无法匹配而返回的默认IP 0.0.0.0

google了一下，没有结果。

继续想办法。发现不影响获取其它客户端（非本机）IP。根据此现象，我想应该是localhost引起的，于是查看host映射，果然发现::1

(Host映射查看方法 C:\Windows\System32\drivers\etc 文件hosts)

# Copyright (c) 1993-2006 Microsoft Corp.

#

# This is a sample HOSTS file used by Microsoft TCP/IP for Windows.

#

# This file contains the mappings of IP addresses to host names. Each

# entry should be kept on an individual line. The IP address should

# be placed in the first column followed by the corresponding host name.

# The IP address and the host name should be separated by at least one

# space.

#

# Additionally, comments (such as these) may be inserted on individual

# lines or following the machine name denoted by a '#' symbol.

#

# For example:

#

# 102.54.94.97 rhino.acme.com # source server

# 38.25.63.10 x.acme.com # x client host

127.0.0.1 localhost

::1 localhost

原来是因为操作系统开启了IPV6，它对localhost进行了映射的原因。如果我们需要获取的IP是IPV4的，那么可以删掉::1映射。

如果将来我们需要获取的是IPV6的IP，那么就需要这样的映射。然后程序里统一实现获取IPv6的代码。