将 Ubuntu Desktop Server 从 12.04 升级到 14.04 LTS 后无法连接到互联网。我也尝试发出apt-get update命令，但出现以下错误：
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
我没有更改网络配置中的任何内容（见下文）
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)
输出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
对此有什么建议吗？
更新
~$ 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