Sem conexão com a internet após a atualização de 12.04 para 14.04 LTS

Question

Atualizei o Ubuntu Desktop Server de 12.04 para 14.04 LTS e ele não pode se conectar à internet depois. Eu também tentei emitir o comando apt-get update , mas recebo um erro como abaixo:

Err http://ph.archive.ubuntu.com trusty InRelease

Err http://ph.archive.ubuntu.com trusty-updates InRelease

Err http://ph.archive.ubuntu.com trusty-backports InRelease

Err http://security.ubuntu.com trusty-security InRelease

Err http://extras.ubuntu.com trusty InRelease

Reading package lists... Done
W: Failed to fetch http://ph.archive.ubuntu.com/ubuntu/dists/trusty/InRelease

W: Failed to fetch http://ph.archive.ubuntu.com/ubuntu/dists/trusty-updates/InRelease

W: Failed to fetch http://ph.archive.ubuntu.com/ubuntu/dists/trusty-backports/InRelease

W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/trusty-security/InRelease

Eu não mudei nada na configuração da minha rede (veja abaixo)

eth0      Link encap:Ethernet  HWaddr b8:ac:6f:24:6c:7c
          inet addr:192.168.23.133  Bcast:192.168.23.255  Mask:255.255.255.0
          inet6 addr: fe80::baac:6fff:fe24:6c7c/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:44316 errors:0 dropped:0 overruns:0 frame:0
          TX packets:1103 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:4004261 (4.0 MB)  TX bytes:176751 (176.7 KB)
          Interrupt:21 Memory:fe6e0000-fe700000

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:511 errors:0 dropped:0 overruns:0 frame:0
          TX packets:511 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:40241 (40.2 KB)  TX bytes:40241 (40.2 KB)

virbr0    Link encap:Ethernet  HWaddr ee:6e:1d:9b:48:fb
          inet addr:192.168.122.1  Bcast:192.168.122.255  Mask:255.255.255.0
          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:0
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

Saída de cat /etc/network/interfaces

auto lo
iface lo inet loopback


auto eth0
iface eth0 inet static
address 192.168.23.133
netmask 255.255.255.0
broadcast 192.168.23.255
gateway 192.168.23.17

Algum conselho sobre isso?

Atualizar

~$ ping google.com
ping: unknown host google.com


~$ route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         192.168.23.17   0.0.0.0         UG    0      0        0 eth0
169.254.0.0     0.0.0.0         255.255.0.0     U     1000   0        0 eth0
192.168.23.0    0.0.0.0         255.255.255.0   U     0      0        0 eth0
192.168.122.0   0.0.0.0         255.255.255.0   U     0      0        0 virbr0

cat /etc/resolv.conf
# 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