DNS

resolv.conf改动问题（2010年10月5日）

用了VPN后，VPN推送的DNS追加到了resolv.conf的后面，而不是前面，这样就没什么用了。我以为是NetworkManager的bug，在Launchpad和GNOME的Bugzilla上都汇报了bug。后来发现是resolvconf程序搞的，删除了就好了。

如果安装了resolvconf，那么VPN推送的DNS会被resolvconf追加到/etc/resolv.conf后面，它替代了NetworkManager处理DNS的工作；如果没有安装resolvconf，则NetworkManager把DNS插入在/etc/resolv.conf的前面。这和是否ADSL直连还是通过路由器上网没有关系。

ping和nslookup的结果不同？（2010年9月11日）

在Windows下启用OpenVPN后，对twitter，youtube等被DNS污染的网站，ping和nslookup返回的IP不同呢？ping返回的是错误的IP，nslookup返回的是正确的IP。

查询Twitter.com的结果：

C:\Documents and Settings\Limo>ping twitter.com

Pinging twitter.com [37.61.54.158] with 32 bytes of data:

Request timed out.

Ping statistics for 37.61.54.158:

Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),

C:\Documents and Settings\Limo>nslookup twitter.com

Server: vnsc-pri.sys.gtei.net

Address: 4.2.2.1

Non-authoritative answer:

Name: twitter.com

Addresses: 128.242.240.244, 168.143.162.68, 128.242.240.212

下面是Youtube.com的结果：

C:\Documents and Settings\Limo>ping youtube.com

Pinging youtube.com [8.7.198.45] with 32 bytes of data:

Request timed out.

Ping statistics for 8.7.198.45:

Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),

C:\Documents and Settings\Limo>nslookup youtube.com

Server: vnsc-pri.sys.gtei.net

Address: 4.2.2.1

Non-authoritative answer:

Name: youtube.com

Addresses: 74.125.127.93, 74.125.95.93