终于搞定了部分网站无法打开的问题

最近机器出现一个烦人的问题：有些网站无法打开，最初以为是实验室网络的问题，后来发现别人的机器能打开，于是开始折腾自己的机器了。hosts文件没有异常，关掉杀毒软件、防火墙，症状依旧：

在浏览器地址栏中敲入url回车之后，浏览器很快报错无法访问，特别干脆。于是在cmd中ping，报错：Ping request could not find host ***，nslookup能正常解析出IP地址，然后ping解析出来的ip地址，竟然能ping通！然后在浏览器中用ip地址访问，也能访问。这就奇怪了，既然nslookup能解析，浏览器为什么就不能解析呢？而且其它网站也没有这个问题啊，目前发现3个网站有这个问题，而且也都是正经网站啊，其中包括micsoft.com。有些茫然，google一下，找到一个解决办法，照着整呗，竟然搞定了！且看：

（from：http://www.windowsreference.com/windows-vista/fix-for-ping-request-could-not-find-host-fqdn-of-server-error/）
When you try to connect to server by fully qualified domain name (FQDN) which resides in top level domain (TLD) that has a purely numeric suffix, connection is failed. If server is domain controller issue also affects establishing trusts and domain joins.
When you try to PING server by FQDN you receive the following error message:
Ping request could not find host “FQDN of server”. Please check the name and try again.
Connection to the server by IP or by NetBIOS name is succeeding.When this issue occurs, all Domain Name System (DNS) records are correctly returned by NSLOOKUP. Therefore, DNS is fully functional and is not part of this issue.
By default DNS client service rejects resolution of DNS records in top level domain (TLD) that has a purely numeric suffix.
Procedure to Follow
To resolve this problem, add the ScreenBadTlds registry entry and restart DNS client service. Adding this registry entry prevents the DNS client service from performing the test to determine whether the top level domain is supported.
To add this registry entry and restart DNS client service, follow these steps.
1. Click Start, and then click Run, type regedit in Open box, and then press ENTER.
2. Locate and then click the following registry subkey:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Dnscache\Parameters
3. On the Edit menu, point to New, and then click DWORD Value.
4. Type ScreenBadTlds, and then press ENTER.
5. Right-click ScreenBadTlds, and then click Modify.
6. In the Value data box, type 0, and then click OK.
7. Exit Registry Editor.
8. Stop and then start the DNS client service. To do so:
a.  Click Start, and then click Run.
b.  In the Open box, type cmd, and then click OK.
c.  At the command prompt, type the following lines. Press ENTER after each line
net stop DNScache
net start DNScache
d.  Type exit to quit Command Prompt.

如果机器有类似问题的朋友不妨试试，很管用。不过还是不清楚为什么要在注册表添加一个参数？如果有知道的朋友还请回帖告知~谢谢！