I have upgraded from 14.04 about a week ago and now my internet connection is slow. It is only slow on this computer and I cannot figure what is going wrong.

From my searching I have found that it could be that IPv6 is slowing down my connection. Issuing the command cat /proc/sys/net/ipv6/conf/all/disable_ipv6 reports 1 and this should mean that IPv6 is disable but the problem persists. Even after a reboot.

Any ideas? If this can't be worked out I may just go back to 14.04.


EDIT: Here are the results from speedtest.net on the Ubuntu 16.04 computer: Ping: 9ms, Download 8.99 Mbps, UPLOAD 0.96 Mbps. These numbers are not far from what I'm paying for. Maybe the problem is different; although I experience the same slow speeds in both firefox and google chrome.

Anyway, here are the results from the various network commands:

ifconfig -a

enp2s0    Link encap:Ethernet  HWaddr 08:60:6e:82:a1:50  
      inet addr:  Bcast:  Mask:
      RX packets:301143 errors:0 dropped:0 overruns:0 frame:0
      TX packets:169836 errors:0 dropped:0 overruns:0 carrier:0
      collisions:0 txqueuelen:1000 
      RX bytes:393327698 (393.3 MB)  TX bytes:18792937 (18.7 MB)

lo        Link encap:Local Loopback  
      inet addr:  Mask:
      UP LOOPBACK RUNNING  MTU:65536  Metric:1
      RX packets:1195 errors:0 dropped:0 overruns:0 frame:0
      TX packets:1195 errors:0 dropped:0 overruns:0 carrier:0
      collisions:0 txqueuelen:1 
      RX bytes:104670 (104.6 KB)  TX bytes:104670 (104.6 KB)


lspci | grep Eth

02:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. 
RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 09)

Next again.

                description: Ethernet interface
                product: RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller
                vendor: Realtek Semiconductor Co., Ltd.
                physical id: 0
                bus info: pci@0000:02:00.0
                logical name: enp2s0
                version: 09
                serial: 08:60:6e:82:a1:50
                size: 100Mbit/s
                capacity: 1Gbit/s
                width: 64 bits
                clock: 33MHz
                capabilities: pm msi pciexpress msix vpd bus_master cap_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd 1000bt 1000bt-fd autonegotiation
                configuration: autonegotiation=on broadcast=yes driver=r8169 driverversion=2.3LK-NAPI duplex=full firmware=rtl8168f-1_0.0.5 06/18/12 ip= latency=0 link=yes multicast=yes port=MII speed=100Mbit/s
                resources: irq:26 ioport:e800(size=256) memory:fafff000-faffffff memory:faff8000-faffbfff

Lastly, lsmod | grep driver_name_in_lshw does not display anything.

Thanks for the help!


Not to doubt your analysis but to take the subjectivity out of what's "slow", do a speed test


Assuming your ethernet is indeed running slow, find out if the NIC is generating errors, dropped packets and so on

ifconfig -a

Check to see if the correct driver is installed

lspci | grep Eth - Described the Eth hardware

lshw - scroll down to the Eth HW section and see what driver is installed

lsmod | grep driver_name_in_lshw

IPv6 should not be a factor unless there is a bug in 16.06

  • Thanks for the reply. I meant 16.04 in the title, sorry about that. The reason I say that IPv4 could be slowing my connection is because of these links: askubuntu.com/questions/764387/… help.ubuntu.com/community/WebBrowsingSlowIPv6IPv4 I'll Edit my OP comment with outputs to those commands. – JustHeavy Jun 16 '17 at 4:29
  • Off the top I think the IPv6 thing could be a red herring. The "bug" only seems to effect DNS lookups which will not be a factor if you run the speedtest I mentioned in my answer. If speedtest shows that your NIC is operating at about the maximum speed for the Internet connection you have, then taking a look at how long DNS lookups take might make sense. I've been running 16.04 on several machines for a very long time and the e-net speed is rock solid. – jones0610 Jun 16 '17 at 4:47

You have one, or both, of a couple of problems...

  • you're only connecting at 100mbit when your interface can do 1gbit. Check/replace your ethernet cable with a cat5 or better cable, or a gigabit switch/hub/router with a hosed port... a power off/on may fix problems with these.

  • the r8169 driver is buggy. Replace it with r8168-dkms.

In terminal...

sudo apt-get update

sudo apt-get install r8168-dkms

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