Ubuntu (alternate) server 18.04: no network interfaces

Question

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

Were there any specific error messages shown while installing as to why no interface was detected? Please run systemctl systemd-networkd and lets see if your networld is running! — George Udosen, Dec 09 '18 at 21:23
Do you wish to use wireless or ethernet? Please edit your question to add the result of the terminal command: cat /etc/netplan/*.yaml — chili555, Dec 10 '18 at 00:15
@GeorgeUdosen systemd-networkd following systemctl does not exist! — user10853, Dec 10 '18 at 13:47
Your ip addr show doesn't include ethernet. As well, we doubt that it is named eth0. Please clarify. I will propose an answer covering wireless only at this time until there are further details. — chili555, Dec 10 '18 at 14:35
@chili555 probably because I do not have the adapter plugged in. The ethernet is received through the usb type-C adapter. I remember it was eth0 when I used to connect on my ubutnu desktop (on this laptop). — user10853, Dec 10 '18 at 17:54
Start that service with sudo systemctl start systemd-networkd && sudo systemctl enable systemd-networkd — George Udosen, Dec 10 '18 at 18:38
Now connect your ethernet cable and let's see how networkd handles it. — George Udosen, Dec 10 '18 at 19:25
When I said it is active I was referring to the wifi wlp2s0. The eth0 is not shown in ip addr show as I do not have it connected (not with me right now). I will try it about 2 hours when I have it with me. — user10853, Dec 10 '18 at 19:33

chili555 · Answer 1 · 2018-12-10T20:39:52.157

4

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

edited Dec 10 '18 at 20:39

answered Dec 10 '18 at 14:46

chili555

60,188

No it does not connect. No IP – user10853 Dec 10 '18 at 19:30
Well, I am very embarassed! I warned about intentation and made just such a mistake myself! Please see my edit above in a few moments. After making the correction, again run: sudo netplan generate followed by: sudo netplan apply Note and post any errors or warnings. Sorry for my misstep. – chili555 Dec 10 '18 at 20:37
No problem. I tried it but it doesn't work. I mean I don't have a connection. – user10853 Dec 10 '18 at 22:46
Is there any clue in the log? dmesg | grep wlp Please edit your question to show the result. – chili555 Dec 10 '18 at 22:49
After a fresh boot I get wlp2s0: renamed from wlan0 – user10853 Dec 11 '18 at 21:42
I had something else in /etc/netplan/01-netcdg.yaml. I was testing something yesterday. After changing it back dmesg also shows wlp2s0: link is not ready. No ip address though and ping returns Temporary failure in name resolution. – user10853 Dec 11 '18 at 21:50
It's time to dive deep. Please download and run the wireless script from here: https://askubuntu.com/questions/425155/my-wireless-wifi-connection-does-not-work-what-information-is-needed-to-diagnos/425180#425180 Paste the result here and give us the link: http://paste.ubuntu.com – chili555 Dec 11 '18 at 22:30

Ubuntu (alternate) server 18.04: no network interfaces

1 Answers1