我正在尝试安装软件包，但无法访问任何 DNS，但当我手动将 DNS 添加到 IP 时它可以工作，但最后的 DNS 记录仍然失败。
# cat /etc/hosts
127.0.0.1 localhost
127.0.1.1 sun-Alienware-X51
91.189.91.15 us.archive.ubuntu.com
91.189.92.152 extras.ubuntu.com
91.189.92.184 security.ubuntu.com
91.189.94.156 ubuntu.com
# The following lines are desirable for IPv6 capable hosts
::1 ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
# dig ubuntu.com
; <<>> DiG 9.8.1-P1 <<>> ubuntu.com
;; global options: +cmd
;; connection timed out; no servers could be reached
#/var/tmp/dist# apt-get update
Ign http://us.archive.ubuntu.com precise InRelease
Ign http://us.archive.ubuntu.com precise-updates InRelease
Ign http://us.archive.ubuntu.com precise-backports InRelease
Err http://extras.ubuntu.com precise InRelease
Err http://extras.ubuntu.com precise Release.gpg
Unable to connect to extras.ubuntu.com:http:
Hit http://us.archive.ubuntu.com precise Release.gpg
Hit http://us.archive.ubuntu.com precise-updates Release.gpg
Ign http://security.ubuntu.com precise-security InRelease
Hit http://us.archive.ubuntu.com precise-backports Release.gpg
Hit http://us.archive.ubuntu.com precise Release
Hit http://security.ubuntu.com precise-security Release.gpg
Hit http://us.archive.ubuntu.com precise-updates Release
Hit http://us.archive.ubuntu.com precise-backports Release
Hit http://us.archive.ubuntu.com precise/main Sources
Hit http://us.archive.ubuntu.com precise/restricted Sources
Hit http://us.archive.ubuntu.com precise/universe Sources
Hit http://us.archive.ubuntu.com precise/multiverse Sources
Hit http://us.archive.ubuntu.com precise/main amd64 Packages
Hit http://security.ubuntu.com precise-security Release
Hit http://us.archive.ubuntu.com precise/restricted amd64 Packages
Hit http://us.archive.ubuntu.com precise/universe amd64 Packages
Hit http://us.archive.ubuntu.com precise/multiverse amd64 Packages
Hit http://us.archive.ubuntu.com precise/main i386 Packages
Hit http://us.archive.ubuntu.com precise/restricted i386 Packages
Hit http://us.archive.ubuntu.com precise/universe i386 Packages
Hit http://us.archive.ubuntu.com precise/multiverse i386 Packages
Hit http://us.archive.ubuntu.com precise/main TranslationIndex
Hit http://us.archive.ubuntu.com precise/multiverse TranslationIndex
Hit http://us.archive.ubuntu.com precise/restricted TranslationIndex
Hit http://us.archive.ubuntu.com precise/universe TranslationIndex
Hit http://us.archive.ubuntu.com precise-updates/main Sources
Hit http://us.archive.ubuntu.com precise-updates/restricted Sources
Hit http://us.archive.ubuntu.com precise-updates/universe Sources
Hit http://us.archive.ubuntu.com precise-updates/multiverse Sources
Hit http://us.archive.ubuntu.com precise-updates/main amd64 Packages
Hit http://us.archive.ubuntu.com precise-updates/restricted amd64 Packages
Hit http://us.archive.ubuntu.com precise-updates/universe amd64 Packages
Hit http://us.archive.ubuntu.com precise-updates/multiverse amd64 Packages
Hit http://us.archive.ubuntu.com precise-updates/main i386 Packages
Hit http://us.archive.ubuntu.com precise-updates/restricted i386 Packages
Hit http://us.archive.ubuntu.com precise-updates/universe i386 Packages
Hit http://us.archive.ubuntu.com precise-updates/multiverse i386 Packages
Hit http://us.archive.ubuntu.com precise-updates/main TranslationIndex
Hit http://security.ubuntu.com precise-security/main Sources
Hit http://us.archive.ubuntu.com precise-updates/multiverse TranslationIndex
Hit http://us.archive.ubuntu.com precise-updates/restricted TranslationIndex
Hit http://us.archive.ubuntu.com precise-updates/universe TranslationIndex
Hit http://us.archive.ubuntu.com precise-backports/main Sources
Hit http://us.archive.ubuntu.com precise-backports/restricted Sources
Hit http://us.archive.ubuntu.com precise-backports/universe Sources
Hit http://us.archive.ubuntu.com precise-backports/multiverse Sources
Hit http://us.archive.ubuntu.com precise-backports/main amd64 Packages
Hit http://us.archive.ubuntu.com precise-backports/restricted amd64 Packages
Hit http://us.archive.ubuntu.com precise-backports/universe amd64 Packages
Hit http://us.archive.ubuntu.com precise-backports/multiverse amd64 Packages
Hit http://us.archive.ubuntu.com precise-backports/main i386 Packages
Hit http://us.archive.ubuntu.com precise-backports/restricted i386 Packages
Hit http://us.archive.ubuntu.com precise-backports/universe i386 Packages
Hit http://us.archive.ubuntu.com precise-backports/multiverse i386 Packages
Hit http://security.ubuntu.com precise-security/restricted Sources
Hit http://security.ubuntu.com precise-security/universe Sources
Hit http://security.ubuntu.com precise-security/multiverse Sources
Hit http://security.ubuntu.com precise-security/main amd64 Packages
Hit http://security.ubuntu.com precise-security/restricted amd64 Packages
Hit http://us.archive.ubuntu.com precise-backports/main TranslationIndex
Hit http://us.archive.ubuntu.com precise-backports/multiverse TranslationIndex
Hit http://us.archive.ubuntu.com precise-backports/restricted TranslationIndex
Hit http://us.archive.ubuntu.com precise-backports/universe TranslationIndex
Hit http://us.archive.ubuntu.com precise/main Translation-en
Hit http://us.archive.ubuntu.com precise/multiverse Translation-en
Hit http://us.archive.ubuntu.com precise/restricted Translation-en
Hit http://us.archive.ubuntu.com precise/universe Translation-en
Hit http://us.archive.ubuntu.com precise-updates/main Translation-en
Hit http://us.archive.ubuntu.com precise-updates/multiverse Translation-en
Hit http://us.archive.ubuntu.com precise-updates/restricted Translation-en
Hit http://us.archive.ubuntu.com precise-updates/universe Translation-en
Hit http://us.archive.ubuntu.com precise-backports/main Translation-en
Hit http://us.archive.ubuntu.com precise-backports/multiverse Translation-en
Hit http://us.archive.ubuntu.com precise-backports/restricted Translation-en
Hit http://us.archive.ubuntu.com precise-backports/universe Translation-en
Hit http://security.ubuntu.com precise-security/universe amd64 Packages
Hit http://security.ubuntu.com precise-security/multiverse amd64 Packages
Hit http://security.ubuntu.com precise-security/main i386 Packages
Hit http://security.ubuntu.com precise-security/restricted i386 Packages
Hit http://security.ubuntu.com precise-security/universe i386 Packages
Hit http://security.ubuntu.com precise-security/multiverse i386 Packages
Hit http://security.ubuntu.com precise-security/main TranslationIndex
Hit http://security.ubuntu.com precise-security/multiverse TranslationIndex
Hit http://security.ubuntu.com precise-security/restricted TranslationIndex
Hit http://security.ubuntu.com precise-security/universe TranslationIndex
Hit http://security.ubuntu.com precise-security/main Translation-en
Hit http://security.ubuntu.com precise-security/multiverse Translation-en
Hit http://security.ubuntu.com precise-security/restricted Translation-en
Hit http://security.ubuntu.com precise-security/universe Translation-en
Reading package lists... Done
W: Failed to fetch http://extras.ubuntu.com/ubuntu/dists/precise/InRelease
W: Failed to fetch http://extras.ubuntu.com/ubuntu/dists/precise/Release.gpg Unable to connect to extras.ubuntu.com:http:
W: Some index files failed to download. They have been ignored, or old ones used instead.
#/var/tmp/dist# ping extras.ubuntu.com
PING extras.ubuntu.com (91.189.92.152) 56(84) bytes of data.
64 bytes from extras.ubuntu.com (91.189.92.152): icmp_req=1 ttl=50 time=111 ms
64 bytes from extras.ubuntu.com (91.189.92.152): icmp_req=2 ttl=50 time=111 ms
^C
--- extras.ubuntu.com ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1001ms
rtt min/avg/max/mdev = 111.371/111.614/111.858/0.413 ms
答案1
您使用的 DNS 服务器是什么？打开“系统设置”并转到“网络”。您可以从那里更改 DNS 服务器。您的 ISP 应该有您可以使用的服务器，但您也可以尝试其他服务器。我知道 Google 有两个服务器，对我来说很合适8.8.8.8。8.8.4.4
要调试 DNS 问题，您可以使用 dig 和 ping。尝试以下命令：
dig <some-domain.com>
ping <DNS-server-IP-address>
例如，这些值可以是：
dig ubuntu.com
ping 8.8.8.8
如果更改 DNS 服务器不起作用，请在此处发布上述命令的输出。
答案2
尝试时无法解析任何名称
ping google.co.uk检查了我的 /etc/networks/interfaces 后，我发现没有服务器运行，无法启动它。所以我用它重新安装了它
sudo apt-get install bind9
然后重新启动，就sudo apt-get update可以了！就是sudo tasksel这样，我在工作中途停下来，造成了一片混乱！