Ethernet / LAN Keeps disconnecting roughly 5 or 6 mins after plugging it in

[0N3]

As the title says my ethernet keeps disconnecting roughly 5 mins after plugging in the ethernet cable. If I plug it out and back in again it works perfectly for another 5 mins. I have a USB to LAN connection when I use that I have no connections whatsoever, it only happens when I plug the ethernet cable into the on board ethernet port on my laptop. The connection isn't loose and the wire isn't damaged in any way. Any ideas what's causing this? I read somewhere TLP was causing LAN issues and so I uninstalled TLP yet the issue is still their. grateful for any help received on the matter.

Here is the output of lspci:

00:00.0 Host bridge: Intel Corporation 3rd Gen Core processor DRAM Controller (rev 09)
00:01.0 PCI bridge: Intel Corporation Xeon E3-1200 v2/3rd Gen Core processor PCI Express Root Port (rev 09)
00:14.0 USB controller: Intel Corporation 7 Series/C210 Series Chipset Family USB xHCI Host Controller (rev 04)
00:16.0 Communication controller: Intel Corporation 7 Series/C210 Series Chipset Family MEI Controller #1 (rev 04)
00:1a.0 USB controller: Intel Corporation 7 Series/C210 Series Chipset Family USB Enhanced Host Controller #2 (rev 04)
00:1b.0 Audio device: Intel Corporation 7 Series/C210 Series Chipset Family High Definition Audio Controller (rev 04)
00:1c.0 PCI bridge: Intel Corporation 7 Series/C210 Series Chipset Family PCI Express Root Port 1 (rev c4)
00:1c.1 PCI bridge: Intel Corporation 7 Series/C210 Series Chipset Family PCI Express Root Port 2 (rev c4)
00:1d.0 USB controller: Intel Corporation 7 Series/C210 Series Chipset Family USB Enhanced Host Controller #1 (rev 04)
00:1f.0 ISA bridge: Intel Corporation HM76 Express Chipset LPC Controller (rev 04)
00:1f.2 SATA controller: Intel Corporation 7 Series Chipset Family 6-port SATA Controller [AHCI mode] (rev 04)
00:1f.3 SMBus: Intel Corporation 7 Series/C210 Series Chipset Family SMBus Controller (rev 04)
01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Thames [Radeon HD 7500M/7600M Series]
01:00.1 Audio device: Advanced Micro Devices, Inc. [AMD/ATI] Turks/Whistler HDMI Audio [Radeon HD 6000 Series]
07:00.0 Ethernet controller: Qualcomm Atheros AR8161 Gigabit Ethernet (rev 10)
08:00.0 Network controller: Qualcomm Atheros AR9485 Wireless Network Adapter (rev 01)

Here is the output of lspci -knn | grep Eth -A2:

07:00.0 Ethernet controller [0200]: Qualcomm Atheros AR8161 Gigabit Ethernet [1969:1091] (rev 10)
    Subsystem: Toshiba America Info Systems AR8161 Gigabit Ethernet [1179:ff1e]
    Kernel driver in use: alx
    Kernel modules: alx

An update to this I wouldn't say "solved" but by disabling wifi from the network manager app-indicator my LAN never disconnects now. Must be conflicting issue between enabling wifi and enabling networking

[jeremy31]

If the issue returns try the module from my github site as I used Ubuntu 4.4 kernel source code and added some patches from the upstream kernel

sudo apt-get install git linux-headers-generic build-essential
git clone https://github.com/jeremyb31/alx.git
cd alx
cp /usr/src/linux-headers-`uname -r`/.config ./
cp /usr/src/linux-headers-$(uname -r)/Module.symvers ./
make -C /lib/modules/$(uname -r)/build M=$(pwd) modules
sudo cp alx.ko /lib/modules/$(uname -r)/kernel/drivers/net/ethernet/atheros/alx/alx.ko

Reboot and it should work until you get a kernel update then you need to

cd alx
make -C /lib/modules/$(uname -r)/build M=$(pwd) clean
cp /usr/src/linux-headers-`uname -r`/.config ./
cp /usr/src/linux-headers-$(uname -r)/Module.symvers ./
make -C /lib/modules/$(uname -r)/build M=$(pwd) modules
sudo cp alx.ko /lib/modules/$(uname -r)/kernel/drivers/net/ethernet/atheros/alx/alx.ko

Reboot.

Another option is to just go into Network Manager settings for the wired and change the MTU setting to 8192 and see if it works

[0N3]

Ok I tried your first suggestion I have absolutely no internet connection now via ethernet only via wireless now after enabling wifi. How can I undo what you suggested?

Had Git already installed after running the first command:

E: Unable to locate package build
E: Unable to locate package essential

git & build-essential are already the newest versions spotted the typo

[jeremy31]

I missed a - it is supposed to be

sudo apt-get install build-essential

[0N3]

OK performed the above solution and have ethernet back again wil post back shortly if the issue doesn't happen again. Thanks for your help much appreciated!

[jeremy31]

Which solution? My github module or the MTU change? Use just one or the other

I should have had you file a bug report on launchpad but that can be done after the next kernel update. That way we can get Ubuntu to use the upstream fix in this kernel

[0N3]

I used your github so far so good!

Nope still happening I'll try solution 2 whats really weird is that if I am on YouTube say playing a playlist my internet is fine ...... but if I try load a different site say Facebook or whatever it just won't open a new page / tab unless I plug the ethernet cable out and in again

I go into network settings / edit connections but I don't see any option to change the MTU setting to 8192

By disabling wifi all is perfect again

To be honest I 99.9% of the time use LAN / Ethernet so it's not a big issue for me

I tried

sudo subl /etc/network/interfaces

I didn't see any any option to change mtu

Also tried

sudo ifconfig eth0 mtu 8192

and got 

SIOCSIFMTU: No such device

Hope that helps!

[jeremy31]

If my code is used, setting the MTU to 8192 is likely to cause issues

[0N3]

So how to undo your code? Or file a bug report? As I said not a major issue cause it's 99.9% of the time connected via ethernet but if it helps someone else with the issue I'm happy to file a bug report. I'd like to undo your code and maybe try the MTU 8192 setting. Bit of a noob but not afraid to get down and dirty with Ubuntu.

[jeremy31]

What kernel are you using?

uname -a