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user10853
Asked: 2018-12-10 10:14:49 +0800 CST

Ubuntu (alternate) server 18.04: no network interfaces

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I installed Ubuntu 18.04 using the alternate server installer. During the installation no network interfaces were detected.

I could not figure out how to setup networking (neither ethernet nor wifi). For wired networking I have to use a usb Type-C adapter (Dell XPS 15).

Moreover, ifup/ifdown are not installed. How can I configure the network? I eventually want to install the Ubuntu-desktop. The reason I went with the alternate installer is because I wanted more control on the partitioning than the standard installer allows.

In /etc/network/interfaces I had added:

auto eth0
iface eth0 inet dhcp

auto wlp2s0
wpa-ssid <essid>
wpa-psk <pass>

ip add show shows:

1: lo <LOOPBACK,UP,LOWER_UP> mtu ##### qdisq noqueue state UKNOWN group default qlen 1000
    link/loopbac 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet <ip> scope host lo
        valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host lo
        valid_lft forever preferred_lft forever
2: wlp2so: <BROADCAST,MULTICAST> mtu #### qdisc noop state DOWN group default qlen 1000
    link/ether <mac> brd <brd>

cat /etc/netplan/*.yaml outputs:

# This file describes the network interfaces available on your system
# For more information, see netplan(5).
network:
  version: 2
  renderer: networkd

systemctl status systemd-networkd reports:

● systemd-networkd.service - Network Service
   Loaded: loaded (/lib/systemd/system/systemd-networkd.service; disabled; vendor preset: enabled)
   Active: inactive (dead)
     Docs: man:systemd-networkd.service(8)

By the way lshw shows:

network DISABLED
networking wireless network-manager ethernet 18.04

1 Answers

  1. Networking in Ubuntu Server 18.04 and later is handled by netplan and no longer in /etc/network/interfaces. Please remove your additions to that file.

    Please edit your /etc/netplan/01-netcfg.yaml file to read:

    # This file describes the network interfaces available on your system
# For more information, see netplan(5).
network:
  version: 2
  renderer: networkd
  wifis:
    wlp2s0:
      dhcp4: true
      dhcp6: true
      access-points:
        "network_ssid_name":
          password: "**********"

    Please note that the access point name and password are enclosed in quotation marks. Also, netplan is very specific as to indentation and spacing. Please proofread carefully.

    After saving the file, please do:

    sudo netplan generate
sudo netplan apply

    Reboot. Check to see if you connected. Do you have an IP address?

    ip addr show

    Are you connected?

    ping -c3 www.ubuntu.com
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