If you are running proxmox and you are changing the network configuration, you might get the error that you need ifupdown2 to reload network configuration, the solution is very simple. Ifupdown2 is an applicaiton that needs to be installed.
If you are using Proxmox 7 you can simply type the below command in your ssh;
apt install ifupdown2
If above command doens’t work it means you have to configure the repository properly. If you are using enterprise subscription then above must work, otherwise you have to disable to enterprise repostiroy and enable the community repository.
I must say before you install the ifupdown2 command to configure your network you must disbale the enterprise repository and enable communitty repositoryDisable Enterprise Repository
Edit the repository list located in source directory, simply type below command
nano /etc/apt/sources.list.d/pve-enterprise.list
You will see the list of repository add hash “#” in the beggining of the list to disable the list. So your list should look like below
#deb https://enterprise.proxmox.com/debian/pve buster pve-enterprise
Enable Community Repostirory
Now to enable the community repostiry just type below command or copy and paste
nano /etc/apt/sources.list
Copy and paste below lists in your sources.list. The list that appears in your repository looks like below;
deb http://ftp.debian.org/debian buster main contrib deb http://ftp.debian.org/debian buster-updates main contrib
# PVE pve-no-subscription repository provided by proxmox.com,
# NOT recommended for production use
deb http://download.proxmox.com/debian/pve buster pve-no-subscription # security updates
deb http://security.debian.org/debian-security buster/updates main contrib
How to install
Just open the ssh terminal or shell and type first do update and upgrade by typing below commands;
apt get update
Now list will be updated, type below command to upgrade Proxmox
apt get update
Now you are ready to install ifupdown2 just type the below command;
apt install ifupdown2
This procedure will solve the problem that you face when you try to save the network settings using web user interface in proxmox. The error that you get is “you need ifupdown2 to reload network configuration”
We are still using Proxmox because of Cloud Security Challenges.