This article will explain how to switch back networking from NetPlan/CloudInit on Ubuntu 20.04 Focal Fossa Linux to yet now already obsolete networking
managed via /etc/network/interfaces
.
In this tutorial you will learn:
- How to revert to eth0..n network naming convention
- How to install
ifupdown
- How to remove CloudInit
- How to enable networking daemon
Switching back from NetPlan/CloudInit to the now obsolete networking daemon is not supported nor recommended as you might end up with a broken system.
Software Requirements and Conventions Used
Category | Requirements, Conventions or Software Version Used |
---|---|
System | Installed Ubuntu 20.04 or upgraded Ubuntu 20.04 Focal Fossa |
Software | N/A |
Other | Privileged access to your Linux system as root or via the sudo command. |
Conventions |
# – requires given linux commands to be executed with root privileges either directly as a root user or by use of sudo command$ – requires given linux commands to be executed as a regular non-privileged user |
How to switch back networking to /etc/network/interfaces on Ubuntu 20.04 step by step instructions
- First step is to install tools to configure network interfaces
$ sudo apt update $ sudo apt install ifupdown net-tools
- Next, change from current
enp0s3
to old network interfaces naming conventioneth0
. To do so with administrative privileges edit the/etc/default/grub
file anf change the following line:FROM: GRUB_CMDLINE_LINUX="" TO: GRUB_CMDLINE_LINUX="net.ifnames=0 biosdevname=0"
Once ready update Grub with:
$ sudo update-grub
- Reboot your system:
$ sudo reboot
- As root or any administrative user edit the
/etc/network/interfaces
file and seteth0
network interface to obtain the IP address from DHCP:source /etc/network/interfaces.d/* # The loopback network interface auto lo iface lo inet loopback # The primary network interface allow-hotplug eth0 iface eth0 inet dhcp
Check this article if you need to set your network interface to a static IP address.
- Restart
eth0
interface:$ sudo ifdown --force eth0 $ sudo ifup eth0
NOTE
Network restart via/etc/init.d/networking
is not functional. To restart your network use theifdown
andifup
commands as shown above. - At this stage you should have your
eth0
configured. Useifconfig
command to check the networking interface configuration:ifconfig eth0: flags=4163
mtu 1500 inet 192.168.1.28 netmask 255.255.255.0 broadcast 192.168.1.255 inet6 fe80::2dc0:208f:6d8b:f8fc prefixlen 64 scopeid 0x20 ether 08:00:27:a7:75:ad txqueuelen 1000 (Ethernet) RX packets 22820 bytes 33504917 (33.5 MB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 3446 bytes 282861 (282.8 KB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 lo: flags=73 mtu 65536 inet 127.0.0.1 netmask 255.0.0.0 inet6 ::1 prefixlen 128 scopeid 0x10 loop txqueuelen 1000 (Local Loopback) RX packets 409 bytes 34213 (34.2 KB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 409 bytes 34213 (34.2 KB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 -
First disable and stop Configure DNS resolution to eg.
8.8.8.8
nameserver:$ sudo unlink /etc/resolv.conf $ sudo echo nameserver 8.8.8.8 >> /etc/resolv.conf
- Let’s perform soul cleanup. Remove cloud init package:
$ sudo dpkg -P cloud-init $ sudo rm -fr /etc/cloud/
Disable and stop systemd-resolved service:
$ sudo systemctl disable --now systemd-resolved