Since many of the instructions I found on the internet seem to be flawed or at least outdated, here is how I managed to enable two factor authentication (2fa) with (time based) OTP in Ubuntu 22.04 using the Google Authenticator PAM plugin. Note: When using ssh private/public key based authentication, no OTP prompt will be … Continue reading Using two factor authentication for ssh with Ubuntu 22.04
Category: Linux
Preventing accidental data loss with ZFS
I have recently converted the file system of some of our Samba servers from ext4 to ZFS. The idea was to use ZFS's compression feature to reduce the space some excessingly large files consume which can be easily compressed to take less than 1/10 the space. This works fine. Today we found that a directory … Continue reading Preventing accidental data loss with ZFS
When changing your password in a Samba NT domain does not work
I recently set up a Samba Server using Ubuntu 22.04 as an NT domain controller (not Active Directory!). After quite some time fiddling with the settings and finally getting external help it worked. I could successfully add a Windows 10 computer to the domain and then log into it using any of the configured domain … Continue reading When changing your password in a Samba NT domain does not work
A few things I recently learned about PuTTY (the ssh client)
I have been playing around with PuTTY (Yes, I know, a grown man playing with putty evokes some rather odd pictures. I'm talking about the ssh client tool here though). recently and discovered a few things I didn't know. You can specify the user name to connect with I already knew that there is a … Continue reading A few things I recently learned about PuTTY (the ssh client)
Replacing a failed drive in a zfs pool
So I can look it up later: When a drive that is part of a zfs pool fails and has already been physicall replaced in the server. zpool status looks like this: [bash] user@server:~$ zpool status pool: main state: DEGRADED status: One or more devices could not be used because the label is missing or … Continue reading Replacing a failed drive in a zfs pool
Installing Webmin on Ubuntu 22.04 server
As a follow up to my notes on installing Webmin on Ubuntu 16.04 and 18.04 (on 20.04 it worked as in 18.04) now two additional steps are necessary for Ubuntu 22.04. Those steps must be executed as root: Convert Webmin's PGP key to a format that apt can use to verify files: [bash] cat jcameron-key.asc … Continue reading Installing Webmin on Ubuntu 22.04 server
Setting colors for Linux ls command
Those people who selected the default colors for the Linux ls command must have much better eyes than I. E.g. I think that dark blue text on black background is very difficult to read, but apparently they think it is fine. Fortunately it is easy to change these colors by setting the LS_COLORS environment variable. … Continue reading Setting colors for Linux ls command
Thunderbird 102.0.3 no longer asks to accept a self signed certificate for IMAP
One of my computer's hard disk didn't survive a recent power failure so I had to set up its Thunderbird client again (a backup didn't work, don't ask). My internal IMAP server uses a self signed certificate which worked like a charm until now. Normally, the first time Thunderbird connects to the server after the … Continue reading Thunderbird 102.0.3 no longer asks to accept a self signed certificate for IMAP
Some Linux tools for handling and filtering the passwd file
Linux (and other Unixes) store user information in a file called passwd and the associated passwords in another file called shadow, both located in /etc. Both files are text files and use a : as the field separator. I currently have the need to sort and filter these files in various ways. This post is … Continue reading Some Linux tools for handling and filtering the passwd file
30 years of Linux
Just in case you have been living under a rock: Linux is now 30 years old and while it still hasn't conquered the desktop, there are few smart phones that would work without it and also on the server side it's pretty strong (I have been maintaining Linux servers on the side for more than … Continue reading 30 years of Linux