“ping：未知主机google.com”但IP工作正常
我最近从Ubuntu 12.04升级到Ubuntu 14.04。 重新启动后，我连接WiFi和/或LAN连接，无法访问互联网。 我正在使用东芝Satellite C855D。
$ sudo lshw -C network *-network description: Wireless interface product: RTL8188CE 802.11b/g/n WiFi Adapter vendor: Realtek Semiconductor Co., Ltd. physical id: 0 bus info: pci@0000:02:00.0 logical name: wlan0 version: 01 serial: c0:d9:62:8d:39:85 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless configuration: broadcast=yes driver=rtl8192ce driverversion=3.13.0-24-generic firmware=N/A ip=192.168.0.109 latency=0 link=yes multicast=yes wireless=IEEE 802.11bgn resources: irq:16 ioport:3000(size=256) memory:f0200000-f0203fff *-network description: Ethernet interface product: RTL8101E/RTL8102E PCI Express Fast Ethernet controller vendor: Realtek Semiconductor Co., Ltd. physical id: 0 bus info: pci@0000:06:00.0 logical name: eth0 version: 05 serial: 00:8c:fa:49:e0:4d size: 10Mbit/s capacity: 100Mbit/s width: 64 bits clock: 33MHz capabilities: pm msi pciexpress msix vpd bus_master cap_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=r8169 driverversion=2.3LK-NAPI duplex=half firmware=rtl_nic/rtl8105e-1.fw latency=0 link=no multicast=yes port=MII speed=10Mbit/s resources: irq:41 ioport:2000(size=256) memory:f0104000-f0104fff memory:f0100000-f0103fff $ ifconfig -a eth0 Link encap:Ethernet HWaddr 00:8c:fa:49:e0:4d UP BROADCAST MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:65536 Metric:1 RX packets:727 errors:0 dropped:0 overruns:0 frame:0 TX packets:727 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:56993 (56.9 KB) TX bytes:56993 (56.9 KB) wlan0 Link encap:Ethernet HWaddr c0:d9:62:8d:39:85 inet addr:192.168.0.109 Bcast:192.168.0.255 Mask:255.255.255.0 inet6 addr: fe80::c2d9:62ff:fe8d:3985/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:1934 errors:0 dropped:0 overruns:0 frame:0 TX packets:61 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000
$ ping 8.8.8.8 PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data. 64 bytes from 8.8.8.8: icmp_seq=1 ttl=47 time=47.2 ms 64 bytes from 8.8.8.8: icmp_seq=2 ttl=47 time=44.8 ms 64 bytes from 8.8.8.8: icmp_seq=3 ttl=47 time=43.6 ms 64 bytes from 8.8.8.8: icmp_seq=4 ttl=47 time=156 ms
$ ping google.com ping: unknown host google.com
$ nslookup google.com 8.8.8.8 Server: 8.8.8.8 Address: 8.8.8.8#53 Non-authoritative answer: Name: google.com Address: 190.167.241.187 Name: google.com Address: 190.167.241.178 Name: google.com Address: 190.167.241.163 Name: google.com Address: 190.167.241.183 Name: google.com Address: 190.167.241.177 Name: google.com Address: 190.167.241.172 Name: google.com Address: 190.167.241.153 Name: google.com Address: 190.167.241.162 Name: google.com Address: 190.167.241.167 Name: google.com Address: 190.167.241.152 Name: google.com Address: 190.167.241.168 Name: google.com Address: 190.167.241.182 Name: google.com Address: 190.167.241.157 Name: google.com Address: 190.167.241.173 Name: google.com Address: 190.167.241.148 Name: google.com Address: 190.167.241.158
$ cat /etc/resolvconf/resolv.conf.d/head # Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8) # DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN nameserver 8.8.8.8
$ sudo service networking restart stop: Job failed while stopping start: Job is already running: networking
$ nm-tool NetworkManager Tool State: connected (global) - Device: eth0 ----------------------------------------------------------------- Type: Wired Driver: r8169 State: unavailable Default: no HW Address: 00:8C:FA:49:E0:4D Capabilities: Carrier Detect: yes Speed: 100 Mb/s Wired Properties Carrier: off - Device: wlan0 [Honey Nut Cheerios] ------------------------------------------ Type: 802.11 WiFi Driver: rtl8192ce State: connected Default: yes HW Address: C0:D9:62:8D:39:85 Capabilities: Speed: 18 Mb/s Wireless Properties WEP Encryption: yes WPA Encryption: yes WPA2 Encryption: yes Wireless Access Points (* = current AP) *Honey Nut Cheerios: Infra, 00:21:29:EF:11:2D, Freq 2437 MHz, Rate 54 Mb/s, Strength 78 WPA2 Claro8AD: Infra, 00:1A:2B:B0:69:CD, Freq 2462 MHz, Rate 54 Mb/s, Strength 27 WPA2 CLAROB5F570: Infra, 88:25:2C:B5:F5:70, Freq 2412 MHz, Rate 54 Mb/s, Strength 20 WEP WIND30: Infra, 00:1F:FB:68:E3:6C, Freq 2427 MHz, Rate 54 Mb/s, Strength 37 WPA dd-wrt_vap: Infra, 02:1C:10:34:41:15, Freq 2437 MHz, Rate 54 Mb/s, Strength 24 WPA IPv4 Settings: Address: 192.168.0.109 Prefix: 24 (255.255.255.0) Gateway: 192.168.0.1 DNS: 8.8.8.8 DNS: 8.8.4.4
我从12.04升级到14.04时遇到了同样的问题。 我修复它的方法是完全删除并重新安装resolv配置。 见下文
sudo apt-get remove --purge resolvconf && sudo apt-get install --reinstall resolvconf
您的升级似乎没有正确安装您的DNS解析器。
您的DNS服务器未设置或无法正常工作。
DNS服务器基本上将域名（如google.com）转换（解析）为IP地址。 没有IP地址，您无法连接到任何网站。 因此，如果无法解析域名，则无法访问任何网站。
您可以使用Google的DNS服务器来解决此问题：
- 单击屏幕右上角的WiFi图标
- 点击
Edit connections... - 在
Wi-Fi，选择您的网络名称 - 点击
Edit... - 单击“
IPv4 Settings - 将
Additional DNS Servers设置为8.8.8.8, 8.8.4.4（注意点和逗号之间的差异） - 单击“
Save
尝试访问Google以validation您的连接是否正常工作。
这就是问题。 Ubuntu现在默认将127.0.0.1设置为您的名称服务器，将其放在您的resolv.conf中。
您可以使用resolvconf标头function添加标头以包含您的perferred名称服务器，例如google的dns。
将首选名称服务器添加到头文件中：
/etc/resolvconf/resolv.conf.d/head
nameserver 8.8.8.8
务必在线后放置一个换行符（按ENTER键）。 然后重新启动您的网络，您应该全部设置。
这将在您的网络启动时将首选名称服务器置于默认设置的顶部。
您可以通过重新启动计算机或发出此cli来重新启动网络：
sudo service networking restart
通过在终端（ Ctrl + Alt + T ）中运行以下命令来重新创建/etc/resolv.conf ，它应该通过ping解决问题：
sudo dpkg-reconfigure resolvconf
要么
sudo ln -sf /run/resolvconf/resolv.conf /etc/resolv.conf