为什么域名解析结果不相同？

[the_venus]

请问一下，我用gethostbyname()函数解析的域名怎么与用nslookpu 命令解析的不一样，与WSAAsyncGetHostByName()解析的也不一样:举个例子说明一下：
nslookpu www.tsinghua.edu.cn
E:\>nslookup www.tsinghua.edu.cn
Server: dns.whut.edu.cn
Address: 202.114.88.10

Non-authoritative answer:
Name: www.d.tsinghua.edu.cn
Address: 166.111.4.100
Aliases: www.tsinghua.edu.cn

我用我写的一个小程序来解析，结果如下：
Host Name:www.d.tsinghua.edu.cn
Alias:
www.tsinghua.edu.cn
192.108.58.0

程序源码如下：

#include<winsock2.h>
#pragma comment(lib,"ws2_32.lib")
#include<iostream>
using namespace std;
char *hostname="www.tsinghua.edu.cn";

int main()
{
	WSADATA data;
	if(WSAStartup(0x0202,&data)!=0)
	{
		cout<<"Failed to start up:"<<WSAGetLastError()<<endl;
		return -1;
	}
	PHOSTENT pHost=gethostbyname(hostname);
	if(pHost==NULL)
	{
		cout<<"Failed to resolve host name:"<<WSAGetLastError()<<endl;
	}
	cout<<"Host Name:"<<pHost->h_name<<endl;
	cout<<"Alias:"<<endl;
	for(int i=0;pHost->h_aliases[i]!=NULL;i++)
	{
		cout<<pHost->h_aliases[i]<<endl;
	}
	for(int j=0;pHost->h_addr_list[j]!=NULL;j++)
	{
		in_addr addr;
		addr.S_un.S_addr=(LONG)pHost->h_addr_list[j];
		cout<<inet_ntoa(addr)<<endl;
	}
         WSACleanup();
         return 0;
}

这个是用WSAAsyncGetHostByName()函数解析的结果：

HostName:www.d.tsinghua.edu.cn
Aliases:
www.tsinghua.edu.cn
Address type:IPV4.
244.250.18.0

代码如下：
在类的前面定义了一个消息

#define WM_GETHOSTBYNAME

class DemoDlg
{
...
public:
afx_msg void OnGetHostByName(WPARAM wParam,LPARAM lParam);
...

private:
HANDLE m_hGetHost;
char m_host[MAXGETHOSTSTRUCT];
};

在cpp文件中如下：

CDemoDlg::CDemoDlg()
{
...
m_hGetHostByName=NULL;
}

void CDemoDlg::OnGetHostByName(WPARAM wParam,LPARAM lParam)
{
   	HANDLE hGetHost=(HANDLE)wParam;
	if (hGetHost==m_hGetHost)
	{
		if (WSAGETASYNCERROR(lParam)!=0)
		{
			MessageBox("Failed to Get host by name!",NULL);
			return;
		}
		PHOSTENT pHost=(PHOSTENT)m_host;
		CEdit *pEdit=(CEdit*)GetDlgItem(IDC_EDIT1);
		CString strHostAddr;
		strHostAddr.Empty();
		strHostAddr+="HostName:";
		strHostAddr+=pHost->h_name;
		strHostAddr+="\r\n";
		int i=0;
		strHostAddr+="Aliases:\r\n";
		while (pHost->h_aliases[i]!=NULL)
		{
			strHostAddr+=pHost->h_aliases[i];
			strHostAddr+="\r\n";
			i++;
		}
		if (pHost->h_addrtype==AF_INET)
		{
			strHostAddr+="Address type:IPV4.\r\n";
		}
		else if(pHost->h_addrtype==AF_INET6)
		{
			strHostAddr+="Address type:IPV6\r\n";
		}
		else
		{
			strHostAddr+="UnKnown address type.\r\n";
		}
		if (pHost->h_length==4)
		{
			IN_ADDR inaddr;
			for (int j=0;pHost->h_addr_list[j]!=NULL;j++)
			{
				inaddr.S_un.S_addr=(LONG)pHost->h_addr_list[j];
				strHostAddr+=inet_ntoa(inaddr);
				strHostAddr+="\r\n";
			}
		}
		pEdit->SetWindowText(strHostAddr);
	}
}

void CDemoDlg::OnButton1()
{
    	m_hGetHost=WSAAsyncGetHostByName(m_hWnd,WM_GETHOSTBYNAME,"www.tsinghua.edu.cn",m_host,MAXGETHOSTSTRUCT);
	if(m_hGetHost==NULL)
	{
		CString strErr;
		strErr.Format("Failed to Get host by name:%d\n",WSAGetLastError());
		MessageBox(strErr,NULL,MB_OK|MB_ICONERROR);
	}
}

[the_venus]

有点错误呀
#define WM_GETHOSTBYNAME WM_USER+1
纠正一下！

[covsno]

nslookpu
你用错了

[汪宁宇]

这个教育站估计是双线的机房吧...

可能由于不同DNS的原因，造成解析结果不一样，很正常的！

PS：nslookup小工具实际上也是调用的gethostbyname()

[哈利路亚1874]

一个域名多个服务主机