Home / ubuntu / Questions / 147339
In Process
Jeanno
Asked: 2012-06-07 07:39:52 +0800 CST

Why is my Internet connection randomly dropping?

  • 772

Ever since I have installed 12.04 (clean install not an upgrade), I have been having a drop in the Internet connection. The drop in the connection can be anything from 15 seconds to about 3 mins, and then the connection comes back. This behaviour happens while I am actively browsing the Internet, or if I wake up the computer and open Firefox (sometimes I have connection and sometimes I don't) . Please note that when the Internet connection is on, it is not slow (as speedtest.net results show).

In the beginning, I thought it was a problem with the driver r8169 for my RTL8111/8168B Ethernet card, so I downloaded the r8168 from Realtek website, followed the detailed instructions (blacklisted r8169, changed the file to .bsh ...), but still the same problem persisted.

So I switched to a wireless connection, and I got the same problem with Internet connection dropping randomly.

Any ideas? Thanks in advance.

Output from lspci -v:

00:00.0 Host bridge: Intel Corporation 2nd Generation Core Processor Family DRAM Controller (rev 09)
    Subsystem: Dell Device 04a7
    Flags: bus master, fast devsel, latency 0
    Capabilities: [e0] Vendor Specific Information: Len=0c <?>

00:01.0 PCI bridge: Intel Corporation Xeon E3-1200/2nd Generation Core Processor Family PCI Express Root Port (rev 09) (prog-if 00 [Normal decode])
    Flags: bus master, fast devsel, latency 0
    Bus: primary=00, secondary=01, subordinate=01, sec-latency=0
    I/O behind bridge: 0000e000-0000efff
    Memory behind bridge: f8000000-fa0fffff
    Prefetchable memory behind bridge: 00000000d0000000-00000000dbffffff
    Capabilities: [88] Subsystem: Dell Device 04a7
    Capabilities: [80] Power Management version 3
    Capabilities: [90] MSI: Enable+ Count=1/1 Maskable- 64bit-
    Capabilities: [a0] Express Root Port (Slot+), MSI 00
    Capabilities: [100] Virtual Channel
    Capabilities: [140] Root Complex Link
    Kernel driver in use: pcieport
    Kernel modules: shpchp

00:01.1 PCI bridge: Intel Corporation Xeon E3-1200/2nd Generation Core Processor Family PCI Express Root Port (rev 09) (prog-if 00 [Normal decode])
    Flags: bus master, fast devsel, latency 0
    Bus: primary=00, secondary=02, subordinate=02, sec-latency=0
    I/O behind bridge: 0000d000-0000dfff
    Memory behind bridge: f4000000-f60fffff
    Prefetchable memory behind bridge: 00000000c0000000-00000000cbffffff
    Capabilities: [88] Subsystem: Dell Device 04a7
    Capabilities: [80] Power Management version 3
    Capabilities: [90] MSI: Enable+ Count=1/1 Maskable- 64bit-
    Capabilities: [a0] Express Root Port (Slot+), MSI 00
    Capabilities: [100] Virtual Channel
    Capabilities: [140] Root Complex Link
    Kernel driver in use: pcieport
    Kernel modules: shpchp

00:16.0 Communication controller: Intel Corporation 6 Series/C200 Series Chipset Family MEI Controller #1 (rev 04)
    Subsystem: Dell Device 04a7
    Flags: bus master, fast devsel, latency 0, IRQ 52
    Memory at f6108000 (64-bit, non-prefetchable) [size=16]
    Capabilities: [50] Power Management version 3
    Capabilities: [8c] MSI: Enable+ Count=1/1 Maskable- 64bit+
    Kernel driver in use: mei
    Kernel modules: mei

00:1a.0 USB controller: Intel Corporation 6 Series/C200 Series Chipset Family USB Enhanced Host Controller #2 (rev 05) (prog-if 20 [EHCI])
    Subsystem: Dell Device 04a7
    Flags: bus master, medium devsel, latency 0, IRQ 16
    Memory at f6107000 (32-bit, non-prefetchable) [size=1K]
    Capabilities: [50] Power Management version 2
    Capabilities: [58] Debug port: BAR=1 offset=00a0
    Capabilities: [98] PCI Advanced Features
    Kernel driver in use: ehci_hcd

00:1b.0 Audio device: Intel Corporation 6 Series/C200 Series Chipset Family High Definition Audio Controller (rev 05)
    Subsystem: Dell Device 04a7
    Flags: bus master, fast devsel, latency 0, IRQ 53
    Memory at f6100000 (64-bit, non-prefetchable) [size=16K]
    Capabilities: [50] Power Management version 2
    Capabilities: [60] MSI: Enable+ Count=1/1 Maskable- 64bit+
    Capabilities: [70] Express Root Complex Integrated Endpoint, MSI 00
    Capabilities: [100] Virtual Channel
    Capabilities: [130] Root Complex Link
    Kernel driver in use: snd_hda_intel
    Kernel modules: snd-hda-intel

00:1c.0 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 1 (rev b5) (prog-if 00 [Normal decode])
    Flags: bus master, fast devsel, latency 0
    Bus: primary=00, secondary=03, subordinate=03, sec-latency=0
    Memory behind bridge: fa400000-fa4fffff
    Capabilities: [40] Express Root Port (Slot+), MSI 00
    Capabilities: [80] MSI: Enable- Count=1/1 Maskable- 64bit-
    Capabilities: [90] Subsystem: Dell Device 04a7
    Capabilities: [a0] Power Management version 2
    Kernel driver in use: pcieport
    Kernel modules: shpchp

00:1c.1 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 2 (rev b5) (prog-if 00 [Normal decode])
    Flags: bus master, fast devsel, latency 0
    Bus: primary=00, secondary=04, subordinate=04, sec-latency=0
    I/O behind bridge: 0000c000-0000cfff
    Prefetchable memory behind bridge: 00000000dc100000-00000000dc1fffff
    Capabilities: [40] Express Root Port (Slot+), MSI 00
    Capabilities: [80] MSI: Enable- Count=1/1 Maskable- 64bit-
    Capabilities: [90] Subsystem: Dell Device 04a7
    Capabilities: [a0] Power Management version 2
    Kernel driver in use: pcieport
    Kernel modules: shpchp

00:1c.2 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 3 (rev b5) (prog-if 00 [Normal decode])
    Flags: bus master, fast devsel, latency 0
    Bus: primary=00, secondary=05, subordinate=05, sec-latency=0
    I/O behind bridge: 0000b000-0000bfff
    Memory behind bridge: fa300000-fa3fffff
    Capabilities: [40] Express Root Port (Slot+), MSI 00
    Capabilities: [80] MSI: Enable- Count=1/1 Maskable- 64bit-
    Capabilities: [90] Subsystem: Dell Device 04a7
    Capabilities: [a0] Power Management version 2
    Kernel driver in use: pcieport
    Kernel modules: shpchp

00:1c.3 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 4 (rev b5) (prog-if 00 [Normal decode])
    Flags: bus master, fast devsel, latency 0
    Bus: primary=00, secondary=06, subordinate=06, sec-latency=0
    I/O behind bridge: 0000a000-0000afff
    Memory behind bridge: fa200000-fa2fffff
    Capabilities: [40] Express Root Port (Slot+), MSI 00
    Capabilities: [80] MSI: Enable- Count=1/1 Maskable- 64bit-
    Capabilities: [90] Subsystem: Dell Device 04a7
    Capabilities: [a0] Power Management version 2
    Kernel driver in use: pcieport
    Kernel modules: shpchp

00:1d.0 USB controller: Intel Corporation 6 Series/C200 Series Chipset Family USB Enhanced Host Controller #1 (rev 05) (prog-if 20 [EHCI])
    Subsystem: Dell Device 04a7
    Flags: bus master, medium devsel, latency 0, IRQ 23
    Memory at f6106000 (32-bit, non-prefetchable) [size=1K]
    Capabilities: [50] Power Management version 2
    Capabilities: [58] Debug port: BAR=1 offset=00a0
    Capabilities: [98] PCI Advanced Features
    Kernel driver in use: ehci_hcd

00:1f.0 ISA bridge: Intel Corporation P67 Express Chipset Family LPC Controller (rev 05)
    Subsystem: Dell Device 04a7
    Flags: bus master, medium devsel, latency 0
    Capabilities: [e0] Vendor Specific Information: Len=0c <?>
    Kernel modules: iTCO_wdt

00:1f.2 RAID bus controller: Intel Corporation 82801 SATA Controller [RAID mode] (rev 05)
    Subsystem: Dell Device 04a7
    Flags: bus master, 66MHz, medium devsel, latency 0, IRQ 42
    I/O ports at f070 [size=8]
    I/O ports at f060 [size=4]
    I/O ports at f050 [size=8]
    I/O ports at f040 [size=4]
    I/O ports at f020 [size=32]
    Memory at f6105000 (32-bit, non-prefetchable) [size=2K]
    Capabilities: [80] MSI: Enable+ Count=1/1 Maskable- 64bit-
    Capabilities: [70] Power Management version 3
    Capabilities: [a8] SATA HBA v1.0
    Capabilities: [b0] PCI Advanced Features
    Kernel driver in use: ahci

00:1f.3 SMBus: Intel Corporation 6 Series/C200 Series Chipset Family SMBus Controller (rev 05)
    Subsystem: Dell Device 04a7
    Flags: medium devsel, IRQ 5
    Memory at f6104000 (64-bit, non-prefetchable) [size=256]
    I/O ports at f000 [size=32]
    Kernel modules: i2c-i801

01:00.0 VGA compatible controller: NVIDIA Corporation Device 0dc5 (rev a1) (prog-if 00 [VGA controller])
    Subsystem: NVIDIA Corporation Device 085b
    Flags: bus master, fast devsel, latency 0, IRQ 16
    Memory at f8000000 (32-bit, non-prefetchable) [size=16M]
    Memory at d0000000 (64-bit, prefetchable) [size=128M]
    Memory at d8000000 (64-bit, prefetchable) [size=32M]
    I/O ports at e000 [size=128]
    Expansion ROM at fa000000 [disabled] [size=512K]
    Capabilities: [60] Power Management version 3
    Capabilities: [68] MSI: Enable- Count=1/1 Maskable- 64bit+
    Capabilities: [78] Express Endpoint, MSI 00
    Capabilities: [b4] Vendor Specific Information: Len=14 <?>
    Capabilities: [100] Virtual Channel
    Capabilities: [128] Power Budgeting <?>
    Capabilities: [600] Vendor Specific Information: ID=0001 Rev=1 Len=024 <?>
    Kernel driver in use: nouveau
    Kernel modules: nouveau, nvidiafb

01:00.1 Audio device: NVIDIA Corporation GF106 High Definition Audio Controller (rev a1)
    Subsystem: NVIDIA Corporation Device 085b
    Flags: bus master, fast devsel, latency 0, IRQ 17
    Memory at fa080000 (32-bit, non-prefetchable) [size=16K]
    Capabilities: [60] Power Management version 3
    Capabilities: [68] MSI: Enable- Count=1/1 Maskable- 64bit+
    Capabilities: [78] Express Endpoint, MSI 00
    Kernel driver in use: snd_hda_intel
    Kernel modules: snd-hda-intel

02:00.0 VGA compatible controller: NVIDIA Corporation Device 0dc5 (rev a1) (prog-if 00 [VGA controller])
    Subsystem: NVIDIA Corporation Device 085b
    Flags: bus master, fast devsel, latency 0, IRQ 17
    Memory at f4000000 (32-bit, non-prefetchable) [size=32M]
    Memory at c0000000 (64-bit, prefetchable) [size=128M]
    Memory at c8000000 (64-bit, prefetchable) [size=64M]
    I/O ports at d000 [size=128]
    Expansion ROM at f6000000 [disabled] [size=512K]
    Capabilities: [60] Power Management version 3
    Capabilities: [68] MSI: Enable- Count=1/1 Maskable- 64bit+
    Capabilities: [78] Express Endpoint, MSI 00
    Capabilities: [b4] Vendor Specific Information: Len=14 <?>
    Capabilities: [100] Virtual Channel
    Capabilities: [128] Power Budgeting <?>
    Capabilities: [600] Vendor Specific Information: ID=0001 Rev=1 Len=024 <?>
    Kernel driver in use: nouveau
    Kernel modules: nouveau, nvidiafb

02:00.1 Audio device: NVIDIA Corporation GF106 High Definition Audio Controller (rev a1)
    Subsystem: NVIDIA Corporation Device 085b
    Flags: bus master, fast devsel, latency 0, IRQ 18
    Memory at f6080000 (32-bit, non-prefetchable) [size=16K]
    Capabilities: [60] Power Management version 3
    Capabilities: [68] MSI: Enable- Count=1/1 Maskable- 64bit+
    Capabilities: [78] Express Endpoint, MSI 00
    Kernel driver in use: snd_hda_intel
    Kernel modules: snd-hda-intel

03:00.0 USB controller: NEC Corporation uPD720200 USB 3.0 Host Controller (rev 03) (prog-if 30 [XHCI])
    Subsystem: Dell Device 04a7
    Flags: bus master, fast devsel, latency 0, IRQ 16
    Memory at fa400000 (64-bit, non-prefetchable) [size=8K]
    Capabilities: [50] Power Management version 3
    Capabilities: [70] MSI: Enable- Count=1/8 Maskable- 64bit+
    Capabilities: [90] MSI-X: Enable+ Count=8 Masked-
    Capabilities: [a0] Express Endpoint, MSI 00
    Capabilities: [100] Advanced Error Reporting
    Capabilities: [140] Device Serial Number ff-ff-ff-ff-ff-ff-ff-ff
    Capabilities: [150] Latency Tolerance Reporting
    Kernel driver in use: xhci_hcd

04:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168B PCI Express Gigabit Ethernet controller (rev 06)
    Subsystem: Dell Device 04a7
    Flags: bus master, fast devsel, latency 0, IRQ 51
    I/O ports at c000 [size=256]
    Memory at dc104000 (64-bit, prefetchable) [size=4K]
    Memory at dc100000 (64-bit, prefetchable) [size=16K]
    Capabilities: [40] Power Management version 3
    Capabilities: [50] MSI: Enable+ Count=1/1 Maskable- 64bit+
    Capabilities: [70] Express Endpoint, MSI 01
    Capabilities: [b0] MSI-X: Enable- Count=4 Masked-
    Capabilities: [d0] Vital Product Data
    Capabilities: [100] Advanced Error Reporting
    Capabilities: [140] Virtual Channel
    Capabilities: [160] Device Serial Number 03-00-00-00-68-4c-e0-00
    Kernel driver in use: r8168
    Kernel modules: r8168

05:00.0 FireWire (IEEE 1394): VIA Technologies, Inc. VT6315 Series Firewire Controller (rev 01) (prog-if 10 [OHCI])
    Subsystem: Dell Device 04a7
    Flags: bus master, fast devsel, latency 0, IRQ 18
    Memory at fa300000 (64-bit, non-prefetchable) [size=2K]
    I/O ports at b000 [size=256]
    Capabilities: [50] Power Management version 3
    Capabilities: [80] MSI: Enable- Count=1/1 Maskable+ 64bit+
    Capabilities: [98] Express Endpoint, MSI 00
    Capabilities: [100] Advanced Error Reporting
    Capabilities: [130] Device Serial Number 00-10-dc-ff-ff-cf-56-1a
    Kernel driver in use: firewire_ohci
    Kernel modules: firewire-ohci

06:00.0 SATA controller: JMicron Technology Corp. JMB362 SATA Controller (rev 10) (prog-if 01 [AHCI 1.0])
    Subsystem: Dell Device 04a7
    Flags: bus master, fast devsel, latency 0, IRQ 19
    I/O ports at a040 [size=8]
    I/O ports at a030 [size=4]
    I/O ports at a020 [size=8]
    I/O ports at a010 [size=4]
    I/O ports at a000 [size=16]
    Memory at fa210000 (32-bit, non-prefetchable) [size=512]
    Capabilities: [8c] Power Management version 3
    Capabilities: [50] Express Legacy Endpoint, MSI 00
    Kernel driver in use: ahci

Note that my wireless card is not showing, I have the Ralink 3390 card (which apparently does not show up on Ubuntu for some reason), however I am able to connect to wireless network and connect to the Internet (when it is working).

wireless

6 Answers

  1. Try deleting the connection from the Network Manager and create a new one. (try DSL if you connect with a LAN card or try wireless). It MAY work. I'm not an expert in Ubuntu and I'm not sure this would work. I am a new user and I'm telling this because it worked for me. Hope this helps.

    • 5

  2. There are several reasons for that, possible causes:

    1. your disk have hardware failure, like I/O errors...

    2. You have multiple firewalls enabled, and it is better to have only one, maybe "gufw" is the best... and it needs to deny all with rules to allow out udp 53 and allow out tcp 25,53,80,110,143,843,993,5060,8080

    3. Your OS is not with all modules inserted, type: lsmod > list1.txt Then create an USB installer with the "startup disk creator" using the ISO of your installation CD (a pen of 2 GB is enough) then boot from that USB PEN and choose "try Ubuntu" and type there: lsmod > list2.txt and copy this file to the same location the one above and open both in text editor and see if there is missing modules in list1.txt... To install missing modules use first modinfo "name of the module" after the description see if it needs dependencies and install those first if not, just copy the full path of the ko file and type sudo insmod "paste path/file.ko", after all modules inserted no need for reboot things should start working fine...

    4. If you do not use proprietary driver, then might solve the problem due to the fact that the CPU is having trouble to process all the system in realtime, and that lack of CPU speed and Bridge speed causes wi-fi to disconnect, so try to install proprietary driver for your wireless card or disconnect every USB device that is not needed by your system to connect to the internet. If you do not find how to do this, go to "software center" and type "additional drivers" and if not installed, install it, then start it and activate all drivers available cause it will speed hings up and using less CPU...

    5. This one is certainly your case, you are booting from an USB disk and using very fast speed which causes system resources to collapse, and has to shutdown one, and because the USB disk is the boot disk it chooses to disconnect the Wi-Fi! Solution is to connect the USB disk to an hub of less speed, like if was connected to USB3, use an USB2 hub which causes the USB disk to work at USB2 speed, if it was using USB2 then use an USB1.1 hub...

    6. This is a long shot, and at far, your browser internet agent got corrupt or hacked by some intermediary that poses for an "authority" of contents provided by you, but this is a false authority, and just a cyberbulling occurence, cause there is no internet content that violates internet rules set by the internet authorities, and besides that you or anyone do not have nothing to do with the contents received, because everyone just enters the URL and the server decides which content to send, like, if two guys access the same URL at the same time, they get different pages content cause the server sends data according to lots of parameters and is configured to apply local country rules, like nudity can be considered ilegal in one country and not in other country. There is also the copyright issue but this also is not possible to violate, cause the copyright is not the act of making copies but the act of posing to be the author, that said, if one uploads copyrighted material without trying to own the copyright does not violate any internacional copyright rule. This two are the most common accusations by false "authorities" which makes your agent set your browser ID has an internet criminal act origin, causing every server in the world to disconnect that browser has soon it processes the browser agent, which sometimes takes several minutes...

    • 3

  3. Because you use Ubuntu, you have the possibility to install the Ralink firmware from Debian's repos. To do this, follow the steps below:

    • Add a new line to /etc/apt/sources.list : 
    deb http://ftp.us.debian.org/debian wheezy main contrib non-free # Debian repo for Ralink
    • Install the firmware with this command : 
    sudo apt-get update && sudo apt-get install firmware-ralink

    I hope that this will resolv the problem. (Worked in my case.)

    • 0

  4. I have the same Ethernet card on my laptop. I have the same problem on 11.10 and a blog explained that RTL8111/8168B would have connection problems with the driver in Linux kernel. This blog is written in Chinese: from linux deepin official blog

    It suggests that you can download the official driver from Realtek: http://www.realtek.com.tw/downloads/downloadsView.aspx?Langid=3&PNid=13&PFid=5&Level=5&Conn=4&DownTypeID=3&GetDown=false

    Or just download here: click here

    See the README and install it with "sudo". Hope this will help you.

    • 0

  5. What I have seen work sometimes in this situation is to comment out the eth0 and wlan0 lines in the /etc/network/interfaces file. This leaves your network as unmanaged so you won't be able to use network manager to modify settings, but it does stop the connection dropping. Some wireless cards also don't do well with the 802.11n functionality, I'd refer you to the post which helps you disable that, but for some reason I can't find it again and I didn't save the commands anywhere.

    • 0

  6. Since you are having trouble with both wireless and wired connections I doubt that a problem remains with the firmware for either.

    If there is something sub-optimal with the way your connections are set up, perhaps from when you were struggling with getting the firmware from Realtek working, deleting and recreating them may help. There's an answer here for that. If it doesn't here are some ideas.

    I'd suggest that while your connection is working, you find out the IP address of your router by signing on to the router, and the address of your ISP at the other end of your connection to the ISP (you can probably get this from your router, or call the ISP for it). Also collect the output from netstat -rn, ifconfig, and arp-a.

    Since the problem isn't specific to wired or wireless, the question remains what is it specific to. The best way to answer this is to experiment when the connection isn't working. First, is it connectivity or domain name service oriented?

    If the problem is that you can't get Internet addresses from domain names the problem may lie in domain name server lookup. To check this, try firefox http://74.125.225.212 the next time you are having trouble. That's an address for www.google.com. A problem with resolving domain names is probably the responsibility of your ISP. Your router is probably configured to route domain name requests to your ISP.

    If you can't get to this or other Internet sites by address, it would be a good idea to start with your computer and see how far you can get. You can:

    1. Start by using the ping command and the address of your router and ping n.n.n.n, using the address you got above, as suggested by Eliah. If that works, ping the IP address of the far end of your connection. If that doesn't work look for lights on your connection device and call your ISP. Even if you can ping it but can't ping any Internet sites, it's time to call your ISP. Before calling make sure that netstat -rn on your computer when it is failing has a route for 0.0.0.0 pointing to your router.

    2. Assuming you can't get to your router with ping, double check your ip address and network route table, ifconfig and netstat -rn can be used to compare your network between times it is working and when it is not. For a personal network with no intermediate equipment, the first 3 digits of your IPv4 IP address and that of your router should match. If they do, immediately after pinging your router the command arp -a should give you an answer for the IP address of the router. If the addresses match in the first 3 of the 4 addresses, you ping, but arp doesn't fill in an address, you have trouble with your connectivity to the router.

    3. If that isn't working, try to ping the address of your wireless connector or wired connector, whichever you are using.

    If you are losing the ability to ping your router, one possibility is another device on your network is trying to use the same IP address your computer is using. You can try to turn off any other devices on your network and see if that helps. Another device using the same IP address can mean that sometimes your device will work and sometimes the other one will. Being off for a while gives that other device an edge. If both devices are getting their IP addresses from your router this shouldn't be the problem, but devices configured with a static address can overlap other devices.

    • 0