Networking Server – Fix No Internet Connection on Ubuntu Server 20.04

20.04networkingserver

I tried installing Ubuntu Server 20.04 on my Gigabyte B550i with an Realtek Ethernet Controller and wireless. I want to use ethernet (I don't care about wireless), but I wasn't able to set it up during installation and cat /etc/netplan.*yaml returns just:

network:
      version 2

and lshw -C network lists both networks, the ethernet one unclaimed, the wireless one diabled. /etc/network/interfaces is empty, I tried different file contents, but nothing worked.

What am I doing wrong? I tried installing some kind of drivers, but didn't succeed.

EDIT

ip a returns

1: lo: <LOOPBACK,UP, LOWER_UP> mtu 65536 qdisc noqeue state UNKOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preffered_lft forever
    inet6 ::1/128 scope ost
        valid_lft forever preferred_lft forever
2: wlp6s0 <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
    link/ether 34:cf:f6:b7:d4:8c brd ff:ff:ff:ff:ff:ff:ff

EDIT 2 Images

lshw -C network

lspci -k

Best Answer

Your netplan .yaml file is broken.

ls -al /etc/netplan # get .yaml filename

sudo lshw -C network # identify ethernet device name, enxxxxxx

Edit it with:

sudo pico /etc/netplan/*.yaml <-- change the * to your filename

Initially make its content the following, with EXACLY the same spacing, indentation, and no tabs:

network:
  version: 2
  renderer: networkd
  ethernets:
    en01:
      dhcp4: true
      dhcp6: true
      optional: true
  wifis:
    wlp6s0:
      dhcp4: true
      dhcp6: true
      access-points:
        "YourWifiNetworkName":
          password: "WifiNetworkPassword"

sudo netplan generate

sudo netplan apply

reboot

Update #1:

BIOS

You have BIOS version F1.

The current BIOS is version F2a, dated 6/16/2020, and can be downloaded here.

Note: Confirm that I have the correct web page for your motherboard model #.

Note: Have good backup before updating the BIOS.

kernel

With the newer ethernet controller that you have, you may need to run with a newer kernel than stock from Ubuntu 20.04.1.

Go here to download the latest 5.8.3 kernel. Get the 4 regular .deb files, not the lowlatency files.

Update #2:

Word is that not even kernel 5.8.3 supports the RTL8125! Kernel 5.9 is supposed to support it, but there is only a 5.9-rc2 (rc2 means release candidate #2) version available now... see https://kernel.ubuntu.com/~kernel-ppa/mainline/v5.9-rc2/.

In the mean time, download this Linux driver from Realtek, and it should work. https://www.realtek.com/en/component/zoo/category/network-interface-controllers-10-100-1000m-gigabit-ethernet-pci-express-software. Get the one for "2.5G Ethernet LINUX driver r8125 for kernel up to 5.6"... and use your original 5.4.x kernel.

Update #3:

Ordered a $13 TP-Link USB 3.0 Ethernet dongle to be able to connect and download/install required Ubuntu packages. https://www.amazon.com/dp/B00YUU3KC6

Update #4:

Installed USB to Ethernet adapter. Installed build-essential. Built driver. Everything works. Wireless will be completed when the need arises. Will need to install wpasupplicant.

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