Nicolas Kovacs, a veteran open-source IT expert and Linux instructor, and long-time advocate of CentOS (as well as Slackware), has authored four books, beginning with CentOS 5.3 and ending with CentOS 7.7 (but including an appendix on openSUSE Leap 15). Surprisingly, he also wrote about Ubuntu 9.04 back in the day, yet today he seeks refuge in Debian!

This happens even as he wrote about his multiboot between AlmaLinux 8, Rocky Linux 8, AlmaLinux 9, and Rocky Linux 9, with KDE (for sure)!

Here’s how I discovered his latest change of focus.

I was visiting the debian-user mailing list, and guess what threads I found for January 2026?

❶ Nicolas Kovacs: Testing Linux hardware compatibility using a Debian Live system:

I’ve been working as a Linux trainer for the last two decades. I’m currently transitioning to Debian, after using systems like RHEL clones, SUSE, etc.

Usually I recommend firing up a Linux Live system to get a first impression if the hardware is compatible.

As far as I can tell, Debian has reimplemented non-free firmware in the installer since Debian 12 Bookworm. I’ve tested this in Debian 13 Trixie’s installer, and loading non-free firmware from within the installer is a trivial task.

But what about the Live systems ? Say I’m using the Debian 13 Live KDE system. Does this include non-free firmware ?

According to the information found here it doesn’t:

https://www.debian.org/releases/trixie/amd64/ch03s03.en.html

I’m a bit puzzled. This would mean that some hardware like wireless cards wouldn’t work with the Live version (due to missing non-free firmware) but would work once the system is installed using the Debian installer.

Any suggestions ?

The answer is yes, with limitations, such as firmware-b43-installer_019-14_all.deb and firmware-b43legacy-installer_019-14_all.deb. Note the “installer” in the name: such packages don’t include any firmware but a utility to download a driver from Broadcom and extract the firmware from it. Legally, the firmware is not distributed by Debian but downloaded by the user. Therefore, such packages can be included on the netinst ISO, but their inclusion in a Debian Live ISO wouldn’t make sense, as a Live distro is essentially read-only.

❷ Nicolas Kovacs: Migration from Rocky Linux 9 to Debian 13 – problem with Thunderbird:

I’ve been using Thunderbird since the first release more than two decades ago. I’m handling multiple mail accounts, address books, agenda and tasks with OwnCloud synchronization, RSS feeds, etc.

Up until now, backing up and restoring Thunderbird was a no-brainer. Just transfer the whole ~/.thunderbird directory and its contents to an external hard disk, install or upgrade the system, and then restore the .thunderbird directory to its correct location in ~. I’ve done this hundreds of times for me and some others (I’m a sysadmin in our local school running Linux since 2010).

Right now I have a weird and nasty surprise. I made a backup of my old Rocky Linux 9 installation, installed Debian 13 Trixie, restored the data, moved the .thunderbird directory (about 4 GB) to its correct location in ~, but instead of my mail accounts and my configuration, I just see Thunderbird’s configuration assistant.

Any suggestions ? Did the good folks at Debian change something under the hood for this release ?

No big deal:

I’ll answer this myself, since I just found the solution.

Start Thunderbird on the command line using the -ProfileManager option and then select the correct profile.

❸ Nicolas Kovacs: No sound in MPlayer:

I just installed Debian Trixie KDE on my HP Z440 workstation.

All repositories (including deb-multimedia) are activated.

Besides VLC I also like to use MPlayer. I installed the command-line client. Video works OK, but I have no sound with MPlayer.

Here’s the error message I get when starting a video:

[AO_ALSA] alsa-lib: pcm_hw.c:1803:(snd_pcm_hw_open) open '/dev/snd/pcmC0D0p' failed (-2): No such file or directory
[AO_ALSA] alsa-lib: pcm_dmix.c:1000:(snd_pcm_dmix_open) unable to open slave
[AO_ALSA] Playback open error: No such file or directory
Failed to initialize audio driver 'alsa'
[AO OSS] audio_setup: Can't open audio device /dev/dsp: No such file or directory [AO_ALSA] alsa-lib: pcm_hw.c:1803:(snd_pcm_hw_open) open '/dev/snd/pcmC0D0p' failed (-2): No such file or directory
[AO_ALSA] alsa-lib: pcm_dmix.c:1000:(snd_pcm_dmix_open) unable to open slave
[AO_ALSA] Playback open error: No such file or directory
AO: [pulse] 48000Hz 2ch floatle (4 bytes per sample)
Starting playback…

Any suggestions ?

Primo, deb-multimedia.org is not an official Debian repository and is not recommendable. Secundo, replacing mplayer with mpv fixed it 🙂

❹ Nicolas Kovacs: Create bridge for KVM on local workstation:

I have Debian Trixie with KDE installed on my local HP Z440 workstation.

In the default configuration network is managed by NetworkManager. I have a router in my local network, and the workstation is a DHCP client.

# ip -brief -family inet address show
lo UNKNOWN 127.0.0.1/8
enp3s0 UP 192.168.2.3/24
# nmcli con show
NAME UUID TYPE DEVICE
Wired connection 1 bfe0ecbc-1a65-4487-b7d8-5aaa563286ff ethernet enp3s0
lo 3552564c-088e-4907-ad2d-3b285a8439cc loopback lo

I’d like to create a br0 bridge with enp3s0 as a bridge slave, so I can have virtual machines on this machine connect to the local network.

What’s the Debian way of doing this? Create a bridge with NetworkManager using nmtui? Edit /etc/network/interfaces or some configuration file stub around there?

I’m a long-time Linux user (25 years of experience) but I’m just back from a very (!) long break from Debian.

This is the fix:

If you control the router/DNS/DHCP, then the best move is to drop NetworkManager and use /etc/network/interfaces:

auto enp3s0
auto br0
iface br0 inet static
    bridge_ports enp3s0
    address 192.168.2.3
    netmask 255.255.255.0
    gateway 192.168.2.1

If you don’t control DHCP and have to use it, stick with NetworkManager.

❺ Nicolas Kovacs: Network bridge vs. MAC address question:

This post is more or less a follow-up to yesterday’s post about creating a bridge for KVM, which has brought up an interesting problem. I think this deserves a distinct post on its own.

This morning I tried a little experiment. I installed a minimal AlmaLinux 9.7 on a sandbox PC. And then I created a network bridge using nmtui, because RHEL and clones default to NetworkManager, even on minimal systems. So here’s what I get:

# ip addr
…
2: enp3s0: …
link/ether b0:83:fe:90:4d:64 brd ff:ff:ff:ff:ff:ff
3: br0: …
link/ether b0:83:fe:90:4d:64 brd ff:ff:ff:ff:ff:ff
inet 192.168.2.3/24 brd 192.168.2.255 scope global dynamic noprefixroute br0
valid_lft 86379sec preferred_lft 86379sec
inet6 fe80::b283:feff:fe90:4d64/64 scope link
valid_lft forever preferred_lft forever

Notice how enp3s0 and br0 have the same MAC address ? <== IMPORTANT

I tried this again with AlmaLinux 10.1, with exactly the same result. Same MAC address for enp3s0 and br0. Which is sort of the expected behaviour. <== IMPORTANT

Now I installed a minimal Debian system on this same PC. Here’s the default /etc/network/interfaces as configured by the installer:

allow-hotplug enp3s0
iface enp3s0 inet dhcp

I created a bridge by replacing the above stanza with this:

auto enp3s0
iface enp3s0 inet manual

auto br0
iface br0 inet dhcp
bridge_ports enp3s0

I rebooted and had a bridge OK, but with a different IP address, since now the br0 MAC address IS DISTINCT from the enp3s0 MAC address:

# ip addr
2: enp3s0: …
link/ether b0:83:fe:90:4d:64 brd ff:ff:ff:ff:ff:ff
altname enxb083fe904d64
3: br0: …
link/ether f2:5c:e4:0b:e7:30 brd ff:ff:ff:ff:ff:ff
inet 192.168.2.191/24 brd 192.168.2.255 scope global dynamic noprefixroute br0
valid_lft 86242sec preferred_lft 75442sec
inet6 fe80::9a0d:650b:e751:6e37/64 scope link
valid_lft forever preferred_lft forever

So here’s my question. I’d like my br0 to have the same MAC address as my enp3s0 without having to jump through burning loops.

Any suggestions ?

OMFG. This did the trick:

auto br0
iface br0 inet dhcp
    bridge_ports eth0
    hwaddress ether b0:83:fe:90:4d:64

But then…

Now here’s a follow-up question:

Is there any way I could get the exact same result as with the configuration above, except I’d be using nmtui instead of putting the stuff in /etc/network/interfaces ?

Here’s why: with the above configuration on a workstation, br0 and enp3s0 don’t get handled by NetworkManager anymore… and then when KDE starts up, I get a (wrong) notification about limited connectivity and not being able to connect to the Internet.

Plus, sometimes I like to use ProtonVPN, which I use via NetworkManager.

I don’t know if nmtui offers the equivalent of the following line especially:

hwaddress ether b0:83:fe:90:4d:64

I looked around, but I haven’t managed to find it yet.

Any suggestions ?

Jeez. I happen to know about that KDE bug! KDE loves to have opinions even when it shouldn’t. (Nicolas Kovacs used to be an XFCE guy.) nmtui is documented here.

❻ Nicolas Kovacs: OwnCloud client vs. KWallet vs. keyring mess.

I’m running Debian Trixie with KDE on my HP Z440 workstation. So far everything runs nicely. Currently I’m sanding down a few edges.

I have OwnCloud on a server, and I’m connecting to it via OwnCloud client for file synchronization, tasks, calendar, etc.

Before Debian I had Rocky Linux with KDE from the third-party EPEL repository on this workstation. No KWallet, no GNOME keyring, nothing. I fired up KDE, and I guess the password was stored somewhere under ~/.config/owncloud.

On my fresh Debian install the whole thing’s a mess. Here’s what happens:

1) When I start a session, Kwallet fires up and asks me for my GPG passphrase (because that’s what I chose initially).

2) Then OwnCloud displays a login window and asks for the password. Erm, why? I thought KWallet already handled that ?

3) As soon as I start to type the password, another (!) keyring window pops up in my face and asks me for some password. Erm, which one ?

I don’t know if some of you got similar problems, but how do I get rid of this mess ? I figured out how to deactivate KWallet in the Settings. But what about that keyring popup ? And how do I get OwnCloud to simply store the password somewhere under ~/.config without making me jump through burning loops ?

He clearly has an obsession with jumping through burning loops! But KWallet is a piece of shit and one of the reasons people should not use KDE! But maybe OwnCloud cannot be integrated with KDE.

❼ Nicolas Kovacs: Migrating to Debian – which firewall ?

I’m a long-time Linux user (two and a half decades since Slackware 7.1). I’ve been using RHEL clones mainly for the last ten years or so, on desktops as well as servers (local and Internet-facing). For firewalling I simply chose the default Firewalld.

I understand under Debian there are different possibilities to handle firewalls. As far as I understand, ufw (Uncomplicated firewall) seems to be the default, though Firewalld seems to be an option.

Any recommendations ?

Now, that’s a noob question! Some people recommended firewalld. UFW was meant for Ubuntu. And, of course, iptables still exists (now with iptables-persistent). But in the end…

From the various replies, I gather I can still use Firewalld on Debian. Which would suit me well, because that’s what I’ve been using almost exclusively on Red Hat based systems for the last ten years or so.

❽ Nicolas Kovacs: Kernel options to install Debian over Minicom serial console on PC Engines routerboard:

I have a PC Engines routerboard that has no video card. In the past I’ve successfully installed CentOS and Rocky Linux on this board using Minicom and the serial console.

A couple months ago I even managed to install Debian 13 Trixie on it using the text mode installer in the serial console. Unfortunately I forgot to write down the kernel options I used to boot this thing and now I can’t seem to remember them.

Something like this:

console=ttyUSB0,115200n8 edd=off

But I can’t seem to get to the installer with this. What did I miss ?

WTF is this medieval shit?! OK, he received suggestions, but we don’t know if any of them helped.

So it looks like Niki (or Kiki) is moving to Debian lock, stock, and barrel (avec armes et bagages). But why? Was he disappointed by AlmaLinux and Rocky Linux, or by Red Hat and EPEL?