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Ubuntu 15.04 connects to LAN but not internet

I have a machine using Ubuntu 14.04 that is fine, and I use it constantly as a media server. I have a seldom-used tablet running Ubuntu which I would like to use for some Kahn Academy PHP programming, and perhaps learn how to use an API I have access to. The second machine was originally set up with 14.40, then without my request updated to Ubuntu 15.04. Now I can connect to it using TightVNC, and I can ping it from my (Windows) desktop. But it will not access the internet; "Server not found." I found numerous Google hits with others having the exact problem with Ubuntu 15.04, but the solutions were beyond my personal skill set. Generally they recommend to perform some sort of service or utility, but I need step by step "Type this, then that" level of instruction. I posted this once and the posting got accidentally cancelled, so putting it back up. Previously, there was an opinion that my DNS service was not properly set up, but no instruction how to do so. If this turns out to be really complex, I guess I would entertain just wiping the system and starting over with a fresh install of Ubuntu 14.04.

Can you run the terminal application on both your server and tablet?
If so, run these commands on bot, then post the output.

nslookup www.daringfireball.net
traceroute www.daringfireball.net

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ASKER

Two files attached; a tiny one from the server machine, a large one from Tablet.
Server-Output.txt
Server-Output.txt
Tablet-Output.txt

None of the files has the output from the nslookup and traceroute commands.
What is your network setup? Does your PC get its configuration from DHCP?

ASKER

Not sure what you are asking; I'm pretty rookie with network stuff. I have a new ASUS RT-N900 router (this problem goes way back before this router was installed). I have nearly all nodes set with static IPs. My desk PC is a Windows 7-64 machine, which also has a static IP. The router is 192.168.1.1. If this doesn't answer the question, I guess I need more explicit instructions.

ASKER

My ISP is Comcast. I have my own Linksys cable modem. IP address from Comcast is not static. I note that ASUS mentions UPnP under the WAN configuration page. WAN connection type says "AUtomatic IP." DHCP says "Aggressive query mode."

Can you run the terminal app on the tablet, run the following command and post the output?

ping -c5 8.8.8.8

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Here's the output I got.

PING 8.8.8.8 (8.8.8.8): 56 data bytes
64 bytes from 8.8.8.8: icmp_seq=0 ttl=56 time=13.114 ms
64 bytes from 8.8.8.8: icmp_seq=1 ttl=56 time=28.245 ms
64 bytes from 8.8.8.8: icmp_seq=2 ttl=56 time=14.381 ms
64 bytes from 8.8.8.8: icmp_seq=3 ttl=56 time=14.956 ms
64 bytes from 8.8.8.8: icmp_seq=4 ttl=56 time=14.281 ms

--- 8.8.8.8 ping statistics ---
5 packets transmitted, 5 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 13.114/16.995/28.245/5.657 ms

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ASKER

mike@Ubuntu-Tablet:~$ ping -c5 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=4 ttl=55 time=45.7 ms
64 bytes from 8.8.8.8: icmp_seq=5 ttl=55 time=53.9 ms

--- 8.8.8.8 ping statistics ---
5 packets transmitted, 2 received, 60% packet loss, time 4026ms
rtt min/avg/max/mdev = 45.712/49.850/53.988/4.138 ms

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ASKER

With half the packets failing it seemed that wifi was not working well with the tablet machine. So I just plugged it into CAT5 and reran the ping. This time all were received, with this result:

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=55 time=54.6 ms
64 bytes from 8.8.8.8: icmp_seq=2 ttl=55 time=13.3 ms
64 bytes from 8.8.8.8: icmp_seq=3 ttl=55 time=34.5 ms
64 bytes from 8.8.8.8: icmp_seq=4 ttl=55 time=125 ms
64 bytes from 8.8.8.8: icmp_seq=5 ttl=55 time=86.5 ms

--- 8.8.8.8 ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 4006ms
rtt min/avg/max/mdev = 13.329/62.944/125.621/39.560 ms

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However, still no internet connection.

ASKER

I have a URL I own, so got the IP address and pinged it (198.61.224.144) and it pings just fine. So I'm very confused as to how I can connect to and from the internet but cannot browse.

Your routing is working.
Now let's test DNS.
Try these commands.

ping -c5 www.daringfireball.net
nslookup www.daringfireball.net

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ASKER

mike@Ubuntu-Tablet:~$ ping -c5 www.daringfireball.net
ping: unknown host www.daringfireball.net
mike@Ubuntu-Tablet:~$ nslookup www.daringfireball.net
Server:		127.0.1.1
Address:	127.0.1.1#53

Non-authoritative answer:
Name:	www.daringfireball.net
Address: 199.192.241.217

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ASKER

My son is very experienced in Ubuntu, just not available to come over. His suggestion is to implement Google Name Server; I just don't know how to do that.

It's trying to use a DNS server on your tablet.
I am thinking the DNS server configured for wifi on your router is wrong.

Try this command in the terminal app.

cat /etc/resolv.conf

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ASKER

mike@Ubuntu-Tablet:~$ 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
nameserver 127.0.1.1
search compound

The DNS configuration is definitely the problem.
Do you use a static IP address for your tablet? or do you use DHCP to set its IP address dynamically?

ASKER

Static. But I can go to dynamic of course.

ASKER

Just checked; Tablet is and always has been DCHP; it is not static.

ASKER

I just installed OpenDNS. No change.

ASKER

New data: tried to browse to 173.194.202.106, an IP address for www.Google.com. The address bar on Firefox does change to www.google.com, but still get a "Server not found." So it seems that the name server is working, but something else is not.

With your browser, you connected via the IP address and Google told your browser to request www.google.com, then your tablet couldn't lookup the IP address.

Do you have any other wifi devices connecting to your router for which DNS lookups work properly?

ASKER

Yes, nine. Two of them run Ubuntu plus the tablet, one with iOS, four with Windows. One is wireless, the others are all wired.

Is your tablet wifi only or does it have cellular as well?

We'll add Google DNS server to both the ethernet and wifi network interfaces.

In the tablet's terminal app, run this command.
cat /etc/network/interface

Then I can give you the steps to edit the file.

ASKER

Wired or wifi; no cell. I'll do this now and report. Thanks for sticking with me.

ASKER

Response: No such file or directory.

ASKER

I found the file, and the command needed to be ...interfaces (plural). So I did that, and got this return:

mike@Ubuntu-Tablet:~$ cat /etc/network/interfaces
# interfaces(5) file used by ifup(8) and ifdown(8)
auto lo
iface lo inet loopback

Run the terminal app so you can add Google DNS:

1. sudo vi /etc/network/interfaces
2. tap so the cursor is on the last line of the file
3. press the  o  key on the keyboard to open a new line after the last line of the file.
4. Type the following:
dns-nameservers 8.8.8.8
5. Press the Esc key to get out of edit mode
6. Type the following to write the file and quit
:wq

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Then power off and power on.
Try to browse a web site.

ASKER

Same o, same o. No change. I think perhaps I should just get a copy of 14.04 on a memory stick and start over.

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ASKER

No response, no error message, etc. And no change. In another day or so I'm gonna just start from scratch and install 14.04. I appreciate your effort, but it's been a week and a dozen different strategies, so time to move on. Nothing really important on this machine that I'll lose. Thanks Mark.