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[Solved]Intermittent DNS problem causing broken internet.

Posted: Sat Feb 03, 2018 12:40 pm
by Charlie
I think my internet is being broken by the fact the DNS servers that I added via "Network Settings" in the start menu is losing those values. I use 8.8.8.8 and 8.8.4.4. Intermittently those values vanish and I revert to something like 127.0.1.1 which then leads to my internet becoming unavailable.

After I enter the DNS servers manually and lock them using that facility in Network Settings.

I have also added them in "Edit Connections" via the icon in my taskbar. Those remain unaffected but do not seem to be influential. As soon as I go into "Network Settings" and place the DNS servers in the functionality is restored.

I am using a fresh install.

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 charlie@charlie-ThinkPad-X61 ~ $ inxi -Fxz
System:    Host: charlie-ThinkPad-X61 Kernel: 4.13.0-32-generic x86_64 (64 bit gcc: 5.4.0)
           Desktop: MATE 1.18.0 (Gtk 3.18.9-1ubuntu3.3)
           Distro: Linux Mint 18.2 Sonya
Machine:   System: LENOVO (portable) product: 76757KU v: ThinkPad X61
           Mobo: LENOVO model: 76757KU
           Bios: LENOVO v: 7NETC1WW (2.21 ) date: 10/09/2009
CPU:       Dual core Intel Core2 Duo T7300 (-MCP-) cache: 4096 KB
           flags: (lm nx sse sse2 sse3 ssse3 vmx) bmips: 7979
           clock speeds: max: 2001 MHz 1: 1200 MHz 2: 1200 MHz
Graphics:  Card: Intel Mobile GM965/GL960 Integrated Graphics Controller (primary)
           bus-ID: 00:02.0
           Display Server: X.Org 1.18.4 drivers: intel (unloaded: fbdev,vesa)
           Resolution: 1024x768@60.00hz
           GLX Renderer: Mesa DRI Intel 965GM
           GLX Version: 2.1 Mesa 17.2.4 Direct Rendering: Yes
Audio:     Card Intel 82801H (ICH8 Family) HD Audio Controller
           driver: snd_hda_intel bus-ID: 00:1b.0
           Sound: Advanced Linux Sound Architecture v: k4.13.0-32-generic
Network:   Card-1: Intel 82566MM Gigabit Network Connection
           driver: e1000e v: 3.2.6-k port: 1840 bus-ID: 00:19.0
           IF: enp0s25 state: down mac: <filter>
           Card-2: Intel PRO/Wireless 4965 AG or AGN [Kedron] Network Connection
           driver: iwl4965 v: in-tree: bus-ID: 03:00.0
           IF: wls3 state: up mac: <filter>
Drives:    HDD Total Size: 324.1GB (2.9% used)
           ID-1: /dev/sda model: Hitachi_HTS54501 size: 160.0GB
           ID-2: /dev/sdb model: WDC_WD1600BEVS size: 160.0GB
           ID-3: USB /dev/sdc model: USB_Flash_Disk size: 4.0GB
Partition: ID-1: / size: 144G used: 5.7G (5%) fs: ext4 dev: /dev/dm-1
           ID-2: /boot size: 472M used: 129M (29%) fs: ext2 dev: /dev/sda1
           ID-3: swap-1 size: 3.19GB used: 0.00GB (0%) fs: swap dev: /dev/dm-3
RAID:      No RAID devices: /proc/mdstat, md_mod kernel module present
Sensors:   System Temperatures: cpu: 45.0C mobo: 38.0C
           Fan Speeds (in rpm): cpu: 3415 fan-2: 4947
Info:      Processes: 185 Uptime: 1:21 Memory: 871.6/2976.8MB
           Init: systemd runlevel: 5 Gcc sys: 5.4.0
           Client: Shell (bash 4.3.481) inxi: 2.2.35 
charlie@charlie-ThinkPad-X61 ~ $ 
 

Re: Intermittent DNS problem causing broken internet.

Posted: Sat Feb 03, 2018 12:47 pm
by minitux

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sudo nano /etc/resolvconf/resolv.conf.d/head
add to file those lines

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nameserver 8.8.8.8
nameserver 8.8.4.4
save with Ctrl+o+enter and close with Ctrl+x and in the end

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sudo resolvconf -u
and reboot

in the first command you can sobstitute nano with your text editor.

Re: Intermittent DNS problem causing broken internet.

Posted: Sat Feb 03, 2018 12:56 pm
by trytip
sudo nano /etc/NetworkManager/NetworkManager.conf

comment out dns like this and reboot
[main]
plugins=ifupdown,keyfile,ofono
#dns=dnsmasq

Re: Intermittent DNS problem causing broken internet.

Posted: Sat Feb 03, 2018 1:30 pm
by Charlie
Thanks very much I will try each of those suggestions.

Re: Intermittent DNS problem causing broken internet.

Posted: Sat Feb 03, 2018 5:03 pm
by Charlie
I have implemented both of those suggestions but I don't think the problem is entirely 100% fixed. So I cannot say "solved" just yet.

The vanishing DNS servers has been solved.

I was wondering if my router set-up may be contributing to this broken internet problem. I have two routers linked together via an Ethernet cable, only one has DHCP enabled, the modem router supplied by my ISP, the other has a static IP.

On the second router I have DD-WRT installed and DNSmasq etc was enabled, I have now tried disabling the three settings that were of relevance.

There has been no problem so far, so, so far so good.

Re: Intermittent DNS problem causing broken internet.

Posted: Sun Feb 04, 2018 7:42 am
by Charlie
It seems to be forgetting my WiFi password now. I have enabled WDS/Connection Watchdog on my router which attempts to keep alive the connection, I think it pings the IP address which I have entered, if no reply, it reboots the router.

No idea why the password would be vanishing.

Re: Intermittent DNS problem causing broken internet.

Posted: Sun Feb 04, 2018 8:05 am
by Charlie
It's adding multiple copies of my WiFi connection all by itself.
It's adding multiple copies of my WiFi connection all by itself.
Screenshot at 2018-02-04 11-55-43.png (23.6 KiB) Viewed 359 times

Re: Intermittent DNS problem causing broken internet.

Posted: Sun Feb 04, 2018 2:53 pm
by Charlie
Seems to be working perfectly, but I can't decide what I did that solved it. I deleted all but one instance of WiFi connection as detailed in graphic above, then I altered the name of the remaining instance to "dd-wrt", I lost the "1".

Either that did it OR the "keep alive" tweak on my router did. But, for now, it is looking like solved. Will update when definite and close thread.

Re: Intermittent DNS problem causing broken internet.

Posted: Sun Feb 04, 2018 3:05 pm
by Charlie
Two WiFi devices listed now, I was using the later but now the first.
Two WiFi devices listed now, I was using the later but now the first.

Re: Intermittent DNS problem causing broken internet.

Posted: Mon Feb 05, 2018 8:44 am
by Charlie
It seems like upgrading to "Sylvia" has solved this issue. Perhaps "Sonya" doesn't play well with the latest Kernel.

Re: Intermittent DNS problem causing broken internet.

Posted: Tue Feb 06, 2018 9:50 am
by Charlie
Just did a factory reset of router and a 30-30-30 hoping that will aid connectivity. So far so good.

Re: Intermittent DNS problem causing broken internet.

Posted: Tue Feb 06, 2018 11:45 am
by dwburt
What's 30-30-30?

Re: Intermittent DNS problem causing broken internet.

Posted: Tue Feb 06, 2018 11:49 am
by Charlie
dwburt wrote:What's 30-30-30?
You reset the router by holding a pin or something into the relevant hole. The unit resets to default but you keep holding the pin in position until a count of 30, then unplug the router from the power source and carry on holding for another count of 30, then plug in and carry on holding for another count of 30.

Apparently this clears up any junk retained during a firmware upgrade. Which are frequent in DD-WRT.

Re: Intermittent DNS problem causing broken internet.

Posted: Tue Feb 06, 2018 11:59 am
by Charlie
Charlie wrote:
dwburt wrote:What's 30-30-30?
You reset the router by holding a pin or something into the relevant hole. The unit resets to default but you keep holding the pin in position until a count of 30, then unplug the router from the power source and carry on holding for another count of 30, then plug in and carry on holding for another count of 30.

Apparently this clears up any junk retained during a firmware upgrade. Which are frequent in DD-WRT.
https://www.dd-wrt.com/wiki/index.php/H ... r_30/30/30

Re: Intermittent DNS problem causing broken internet.

Posted: Tue Feb 06, 2018 4:50 pm
by Charlie
Happily I am now calling this solved. The 30-30-30 looks to have completed my fix. Apparently the same thing can be achieved via Telnet and the Terimal, just log into the router and type the commands "erase nvram" then "reboot".