Cannot connect to wired ethernet on ubuntu 16.04

Question

I can't connect to wired ethernet on ubuntu16.04, desktop. I have a dual boot windows10 and the internet works fine there. Not sure how to say this the correct way, the main internet lan is connect to the router, then i use another lan plug into the router and connect it to my computer.

/etc/network/interfaces

# interfaces(5) file used by ifup(8) and ifdown(8)
auto lo
iface lo inet loopback

ifconfig

enp5so
Link encap:Ethernet   HWaddr d0:50:99:59:e3:c8
inet addr:192.168.33.100   Bcast:192.168.33.255  Mask:255.255.255.0
inet6 addr: fe80::a88c:2e2a:16b6:702d/64 Scope:Link
UP BROADCAST RUNNING MULTICAST   MTU:1500   Metric:1
RX packets:585 errors:0 dropped:0 overruns:0 frame:0
TX packets:1643 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:47600 (47.6kb)   TX bytes:142295 (142.2kb)
Interrupt:19

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:30 errors:0 dropped:0 overruns:0 frame:0
TX packets:30 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1
RX bytes:2655 (2.6kb)   TX bytes:2655 (2.6kb)

>

>sudo dhclient -r (no output)
>sudo dhclient enp5s0
RTNETLINK answers: File exists
/etc/resolvconf/update.d/libc: Warning: /etc/resolv.conf is not a symbolic link to /run/resolvconf/resolv.conf
> 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=51 time=306ms
64 bytes from 8.8.8.8 icmp_seq=2 ttl=51 time=307ms
64 bytes from 8.8.8.8 icmp_seq=3 ttl=51 time=306ms
64 bytes from 8.8.8.8 icmp_seq=4 ttl=51 time=306ms
64 bytes from 8.8.8.8 icmp_seq=5 ttl=51 time=305ms
64 bytes from 8.8.8.8 icmp_seq=6 ttl=51 time=305ms
64 bytes from 8.8.8.8 icmp_seq=7 ttl=51 time=304ms
^C
--- 8.8.8.8 ping statistics ---
7 packets transmitted, 7 received, 0%packets loss, time 6000ms
rtt min/avg/max/mdev = 304.573/305.938/307.316/0.978 ms

I have installed ubuntu for serveral months already, normally i need to replug the power for the router on startup, to get the internet working on ubuntu. But last night when i boot up the system, no matter how many times i replug the power, it just not working. And i can't use wifi on my computer, i dont have the wifi card hardware. Help～～

Answer 1

It looks like a DNS issue. You can ping ip addresses, but can't use the internet due to your host not being able to resolve domain names. Check your DHCP server (most likely your router) and ensure that the DNS server(s) defined are functioning properly. You should be able to do a ping test directly from your router. Instead of pinging an IP, try pinging a domain name (google.com). If that fails then you have a DNS problem. Change your DNS servers to point to Google's DNS (8.8.8.8,8.8.4.4) and you should be golden.