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I have a 2Gpbs network connection, and a CAT7 LAN cable connecting my modem to my laptop.

However, Ubuntu shows it only as 100mb/s when I connect the LAN cable. Even my wireless is 300mb/s!

enter image description here

I connected the same LAN cable to a windows machine and it shows close to 1gb/s. So it's definitely not the LAN cable. There's some weird setting that's preventing the proper speed.

Setting up the LAN connection was also a pain, having to set default NetworkManager and what not following a few other answers (No wired connection - Wired unmanaged ubuntu 18.04)

I also tried this solution Cat 6 Only 100mbit speed and ran

sudo ethtool -s enp109s0f1 autoneg off
sudo ethtool -s enp109s0f1 speed 1000 duplex full

but it says

Cannot set new settings: Invalid argument
  not setting speed
  not setting duplex

I'm at a loss and honestly quite tired of this. Does anyone know whats wrong?

Output of sudo lshw -C network:

  *-network                 
       description: Ethernet interface
       product: RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller
       vendor: Realtek Semiconductor Co., Ltd.
       physical id: 0.1
       bus info: pci@0000:6d:00.1
       logical name: enp109s0f1
       version: 12
       serial: 80:fa:5b:3e:6e:9a
       size: 100Mbit/s
       capacity: 1Gbit/s
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress msix vpd bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation
       configuration: autonegotiation=on broadcast=yes driver=r8168 driverversion=8.049.01-NAPI duplex=full ip=192.168.1.116 latency=0 link=yes multicast=yes port=twisted pair speed=100Mbit/s
       resources: irq:127 ioport:d000(size=256) memory:dc204000-dc204fff memory:dc200000-dc203fff
  *-network
       description: Wireless interface
       product: Wireless 8265 / 8275
       vendor: Intel Corporation
       physical id: 0
       bus info: pci@0000:6e:00.0
       logical name: wlp110s0
       version: 78
       serial: 00:28:f8:4a:67:da
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless
       configuration: broadcast=yes driver=iwlwifi driverversion=5.4.0-77-generic firmware=36.77d01142.0 ip=192.168.1.117 latency=0 link=yes multicast=yes wireless=IEEE 802.11
       resources: irq:132 memory:dc100000-dc101fff

Whats inside /etc/NetworkManager/NetworkManager.conf

[main]
plugins=ifupdown,keyfile

[keyfile]

unmanaged-devices=*,except:type:wifi,except:type:wwan,except:type:ethernet


[ifupdown]
managed=true


[device]
wifi.scan-rand-mac-address=no

EDIT: Further info:

According to https://serverfault.com/questions/396782/debian-set-eth0-autoneg-off-speed-1000-duplex-full-invalid-argument , you cannot set autoneg off for base speed 1000. I ran

sudo ethtool -s enp109s0f1 speed 1000 duplex full autoneg on and now it just shows 'cable unplugged' in wired and refuses to use it at all. Ugh.

Wboy
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1 Answers1

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Oh my god after 2 days battling this and trying every solution possible, i finally fixed it.

I was using Linux kernel 5.4.0, which apparently has various ethernet issues. using Ukuu (https://ubunlog.com/en/ukuu-a-tool-to-install-and-update-the-kernel-easily/) I upgraded my kernel to 5.7.13, and this fixed the problem automatically.

I have done everything from every ethtool command to NetworkManager configuration and even reinstalled the realtek driver multiple times, but nothing worked.

TLDR: Upgrade your linux kernel to at least 5.7.13, and the problem will fix itself.

Wboy
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