Handle network configuration on systemd/debian

On debian 9, the network configuration is handled by systemd by default. The settings of the old configuration file /etc/network/interfaces are now in /etc/systemd/network/50-default.network

Webmin does not handled this new systemd config. It stick on /etc/network/interfaces.

You can see it by going to Webmin > Networking > Network Configuration >> Network Interfaces , the tab "Activated at Boot" is always empty on fresh installed systemd / Debian.

And so even you add a failover IP (an alias IP) with the systemd-way, Webmin never see it.

For notice : To add an alias IP on systemd, you should add this Address block at the end of the /etc/systemd/network/50-default.network file :


( note that a Label with a colon ":" will not work, ref: https://github.com/systemd/systemd/issues/4057 )

Adding manually by hand a configuration in /etc/network/interfaces will work, but you need to add the whole configuration for one interface (not only the alias IP for example), so you need to duplicate and rewrite the configuration from /etc/systemd/network/50-default.network.

It seems it's /etc/init.d/networking script that mount interfaces presents in /etc/network/interfaces (because it use ifquery command).

/etc/network/interfaces will also be not supported in future releases, it is now a "legacy" configuration file ( https://www.debian.org/doc/manuals/debian-reference/ch05.en.html#_the_le... ).

So, in fact, actually both /etc/network/interface and /etc/systemd/network/* can set network interfaces, but the default is /etc/systemd/network/*. Can you handled both of them in webmin ?




So does this mean that both the format and file location have changed? It looks from your comment like /etc/systemd/network/50-default.network doesn't follow the same format as /etc/network/interfaces

Exactly, they ditched everything so the whole logic is totally different. How are we supposed to use Cloudmin setup for bridged networking in this situation ?

I bet that Devuan that were wise enough to stick away from systemd will work better with Webmin now... I am to give it a try next week and let you know.


On a fresh new Debian 9.4 the installer is not functioning anymore. I m blocked with the "Unable to open /etc/network/interfaces" message. There are also other issues with postfix, procmail that require manual update.

cp  /etc/systemd/network/50-default.network /etc/network/interfaces did not fix the issue.

I have encountered an "Error reading file : unexpected line '[Match]" while Checking the Configuration.

I was obliged to provide a void "interfaces" files to validate the configuration.

UPDATE: After 8 hours of attempts, my virtual servers are still down with plenty of issues. I m considering going back to debian8. Debian 9 should not be considerate as a Grade A OS in virtualmin.

Hello. Sorry to hear your woes rhizomes. As for me, my ride with Devuan is quite smooth, I have all my bare metal servers up and running with Cloudmin and my 1st Devuan VM was a smooth deployment with the ready-to-import qcow image provided by Devuan (https://mirror.leaseweb.com/devuan/devuan_ascii/virtual/devuan_ascii_2.0...). I had none of the issues you mention rhizomes, and Devuan ascii is basically a debian 9 so I'm very happy :)

I agree with you that Debian 9 is not production-ready for Cloudmin, while so far Devuan Ascii is a much better choice !

My Debian is a debian 9.4 stable. I ve tried 4 reinstalls. Debian 9.4 is not usable with virtualmin.

Thanks for the advice but i want an official Debian. I'll also try Ubuntu 18.04 LTS.

Ubuntu 18.04 LTS is working perfectly. (But i need to migrate 20 virtual servers from debian backups). Debian 9.4 is definitively not well supported.

Joe's picture
Submitted by Joe on Fri, 10/26/2018 - 14:45 Pro Licensee

Debian 9.4 has, like Ubuntu 18.04, the option to use a new network configuration system. Unfortunately, the new system is different from the one Ubuntu 18.04 is using, so we haven't even started to support it (because we haven't even gotten Ubuntu's netplan working well yet...this has been slowed by some events that led to Jamie working without much of his usual infrastructure for an extended period of time, and with less time to devote to new development; temporary, but slowing addition of complicated new features, like supporting a whole new network configuration system).

Anyway, the answer for Debian 9.4 is the same as for Ubuntu: Use the old network configuration system. We'll tackle the new one as soon as we're able, but it's a big change.

Dear Joe. Ubuntu 18.04, works correctly (even network conf)

Debian 9.4 is completely broken (the network is not the only issue) You cannot consider anymore Debian as a Grade A OS in virtualmin. It is nearly impossible to use it.

Joe's picture
Submitted by Joe on Sun, 10/28/2018 - 22:39 Pro Licensee

Debian defaults to the old network configuration, as far as I can tell (it did in my test install). Use that, it works.

We'll add support for the new network configuration in Debian as soon as possible, but it will take some time, as it is very complex.

Hi, I concur that Debian 9 has some other glitches beside network config. It requires more manual install and package add after the install be it command line or the activation of a feature via GUI and automatic installation of required packages.

It's perfectly fine for me if you don' t support the new Debian network system, old one works nice.

Thanks for your effort

Joe's picture
Submitted by Joe on Sun, 11/25/2018 - 17:27 Pro Licensee

What specific problems are you seeing on Debian 9.x when using the old network configuration system? My test installs a few months back went fine, but it seems 9.4+ isn't really compatible with earlier 9.x releases if there are even more problems. (I wish they wouldn't do that. A minor version change really shouldn't break compatibility...)