我可以临时覆盖.NET应用程序中的DNS解析吗？ [英] Can I temporarily override DNS resolution within a .NET application?

问题描述

我有一些包装代码运行一组NUnit测试，扫描实时网站的某些响应代码。

我想要针对不同的服务器。手动运行时，可以通过在Windows \System32 \drivers中编辑/ etc / hosts文件，然后临时将www.mysite.com设置为10.0.0.whatever

有没有办法在.NET控制台应用程序中执行相同的操作？暂时覆盖DNS记录或以某种方式截取分辨率并返回不同的IP地址？ >编辑：这是为了测试一个Web场中的多个服务器。我有三台实时服务器，所有这些服务器都是www.example.com。因为服务器使用HTTP主机头，所以我不能只针对server1，然后是server2，然后是server3来测试，因为HTTP请求要 http ：// server1 / 不会返回与 http：//www.example。 com / 被解析为server1 ...

解决方案

在过去的C ++中，我能够钩住WSOCK32.DLL的gethostbyname函数和重新路由DNS请求。我使用Microsoft Detours库来做到这一点。

对于C＃，我发现这一点： http://easyhook.codeplex.com/ 可能会帮助你。基本上你可以钩住 gethostbyname windows函数并执行自己的代码或返回不同的结果（不同的IP）。

另一种可能的解决方案是在应用程序启动和结束时暂时（和编程性地）编辑主机文件。从您自己的代码。

编辑：我发现我的旧的C ++代码，也许会给你一个提示该怎么做。

$ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ b $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ ret = GetHostByNameFunction（name）;
//检查是否要重新路由的主机名
if（strcmp（host，（char *）name）== 0）
{
//编辑返回的IP由常规gethostbyname
ret-> h_addr_list [0] = hostIP;
ret-> h_length = 15;
}
//返回结果
return ret;
}

EDIT2：找到另一个与较新版本的easyhooks的链接

I have some wrapper code that runs a set of NUnit tests that scan live websites for certain response codes.

I'd like to run these tests against a different server. When running manually, I can do this by editing the /etc/hosts file in Windows\System32\drivers and temporarily setting www.mysite.com to 10.0.0.whatever

Is there any way I can do the same within a .NET console application - temporarily override a DNS record or somehow intercept the resolution and return a different IP address?

EDIT: This is for testing multiple servers in a web farm. I have three live servers, all of which THINK they are www.example.com. Because the servers use HTTP host headers, I can't just run a test against server1, then server2, then server3, because an HTTP request to http://server1/ will NOT return the same thing as a request to http://www.example.com/ that's resolved to server1...

解决方案

In the past with C++ I was able to hook to the WSOCK32.DLL's gethostbyname function and reroute DNS requests. I used the Microsoft Detours library to do that.

As for C# I found this: http://easyhook.codeplex.com/ maybe it will help you. Basically you can hook to the gethostbyname windows function and execute your own code or return a different result (different IP).

The other possible solution is to temporarily (and programatically) edit the hosts file when the application starts and ends. From your own code.

EDIT: I found my old C++ code, maybe it will give you a hint what to do.

struct hostent FAR * WSAAPI MyGetHostByName(IN const char FAR * name)
{
    // Call the regular function 
    struct hostent* ret = GetHostByNameFunction(name);
    // Check if it's the hostname you want to reroute
    if ( strcmp(host, (char*)name) == 0 )
    {
        // Edit the IP returned by the regular gethostbyname
        ret->h_addr_list[0] = hostIP;
        ret->h_length = 15;
    }
    // Return the result
    return ret;
}

EDIT2: Found another link with newer release of easyhooks

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