ubuntu 14.04 server dns 解析不了

root@imeadmin5:/etc/resolvconf/resolv.conf.d# ping www.baidu.com
ping: unknown host www.baidu.com
root@imeadmin5:/etc/resolvconf/resolv.conf.d# lshw -numeric -class network
  *-network:0            
       description: Ethernet interface
       product: 82576 Gigabit Network Connection [8086:10C9]
       vendor: Intel Corporation [8086]
       physical id: 0
       bus info: pci@0000:06:00.0
       logical name: eth0
       version: 01
       serial: c8:0a:a9:57:17:94
       size: 100Mbit/s
       capacity: 1Gbit/s
       width: 32 bits
       clock: 33MHz
       capabilities: pm msi msix pciexpress bus_master cap_list rom ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation
       configuration: autonegotiation=on broadcast=yes driver=igb driverversion=5.0.5-k duplex=full firmware=1.4.3 ip=192.168.1.44 latency=0 link=yes multicast=yes port=twisted pair speed=100Mbit/s
       resources: irq:16 memory:c0200000-c021ffff memory:c0220000-c023ffff ioport:dc00(size=32) memory:c0280000-c0283fff memory:c0000000-c001ffff memory:c0284000-c02a3fff memory:c02a4000-c02c3fff
  *-network:1 DISABLED
       description: Ethernet interface
       product: 82576 Gigabit Network Connection [8086:10C9]
       vendor: Intel Corporation [8086]
       physical id: 0.1
       bus info: pci@0000:06:00.1
       logical name: eth1
       version: 01
       serial: c8:0a:a9:57:17:95
       capacity: 1Gbit/s
       width: 32 bits
       clock: 33MHz
       capabilities: pm msi msix pciexpress bus_master cap_list rom ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation
       configuration: autonegotiation=on broadcast=yes driver=igb driverversion=5.0.5-k firmware=1.4.3 latency=0 link=no multicast=yes port=twisted pair
       resources: irq:17 memory:c0240000-c025ffff memory:c0260000-c027ffff ioport:d880(size=32) memory:c02c4000-c02c7fff memory:c0020000-c003ffff memory:c02c8000-c02e7fff memory:c02e8000-c0307fff
root@imeadmin5:/etc/resolvconf/resolv.conf.d# ping www.baidu.com
ping: unknown host www.baidu.com
root@imeadmin5:/etc/resolvconf/resolv.conf.d# ifconfig -a
eth0      Link encap:Ethernet  HWaddr c8:0a:a9:57:17:94 
          inet addr:192.168.1.44  Bcast:192.168.1.255  Mask:255.255.255.0
          inet6 addr: fe80::ca0a:a9ff:fe57:1794/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:156774 errors:0 dropped:460 overruns:0 frame:0
          TX packets:2263 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:22011322 (22.0 MB)  TX bytes:276365 (276.3 KB)
          Memory:c0200000-c0220000

eth1      Link encap:Ethernet  HWaddr c8:0a:a9:57:17:95 
          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)
          Memory:c0240000-c0260000

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:80 errors:0 dropped:0 overruns:0 frame:0
          TX packets:80 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:5928 (5.9 KB)  TX bytes:5928 (5.9 KB)

root@imeadmin5:/etc/resolvconf/resolv.conf.d# route -nv
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         192.168.1.1     0.0.0.0         UG    0      0        0 eth0
192.168.1.0     0.0.0.0         255.255.255.0   U     0      0        0 eth0
root@imeadmin5:/etc/resolvconf/resolv.conf.d# dhclient -v
Internet Systems Consortium DHCP Client 4.2.4
Copyright 2004-2012 Internet Systems Consortium.
All rights reserved.
For info, please visit https://www.isc.org/software/dhcp/

Listening on LPF/eth0/c8:0a:a9:57:17:94
Sending on   LPF/eth0/c8:0a:a9:57:17:94
Sending on   Socket/fallback
DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 3 (xid=0x3611f68e)
DHCPREQUEST of 192.168.1.79 on eth0 to 255.255.255.255 port 67 (xid=0x3611f68e)
DHCPOFFER of 192.168.1.79 from 192.168.1.1
DHCPACK of 192.168.1.79 from 192.168.1.1
bound to 192.168.1.79 -- renewal in 5430 seconds.
root@imeadmin5:/etc/resolvconf/resolv.conf.d# ping www.baidu.com
PING www.a.shifen.com (119.75.217.109) 56(84) bytes of data.
64 bytes from 119.75.217.109: icmp_seq=1 ttl=53 time=41.4 ms
64 bytes from 119.75.217.109: icmp_seq=2 ttl=53 time=41.9 ms
^C
--- www.a.shifen.com ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1001ms
rtt min/avg/max/mdev = 41.462/41.689/41.916/0.227 ms

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总结 就下面几个命令;（root权限）
#lshw -numeric -class network （list hardware列出 硬件状态信息）
# ifconfig -a （显示所有网络接口）
#route -nv （详细的显示路由信息 ）
# dhclient -v （向dhcp服务器请求ip）