IT for U: 2025

Wednesday, November 26, 2025

Add user to sudoers in Debian 13

1. Войти под root

$ su -

2. Install sudo

# apt install sudo

3. Добавить testuser в sudo

# usermod -aG sudo testuser

Проверить

# groups testuser

Должна быть группа sudo.

4. Перезайти под testuser

$ sudo whoami

Thursday, August 28, 2025

Connecting to a shared printer - error 0x000000cb

Why

Since Sept 2021, Windows requires:

Admin privileges to install any shared driver.
And the driver package must be properly signed and match OS architecture.
If the package doesn’t pass, Windows just errors with 0x000000cb.

Fixes to try:

1. Clear cached printer drivers

On the client:

Run printui /s /t2 → opens Print Server Properties.
Remove all drivers for that printer.
Reboot.

Then try reconnecting.

2. Registry tweak (Point and Print relax)

This is probably what you used before.

On the client PC, set:


[HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows NT\Printers\PointAndPrint]
"RestrictDriverInstallationToAdministrators"=dword:00000000
"NoWarningNoElevationOnInstall"=dword:00000001
"UpdatePromptSettings"=dword:00000001

Or if the PointAndPrint key doesn’t exist, create it.

3. Manually install the driver first

Download the exact printer driver from the manufacturer.
Install it locally on the client.
Then connect to the shared printer again — Windows will reuse the existing driver instead of pulling from the server.

4. Use Group Policy (if in domain)

Path:


Computer Configuration → Administrative Templates → Printers → Point and Print Restrictions

Set Enabled
Configure:
- Users can point and print to: "All servers" (or specify your print server)
- Security prompts: Do not show warning or elevation prompt

5. If nothing works: Connect via TCP/IP port

Instead of SMB share, add the printer as a local printer:

Add Printer → "Add a local printer" → "Create a new port" → Standard TCP/IP Port.
Enter the printer’s IP directly.
Install the driver manually.

This bypasses the SMB Point and Print mechanism entirely.

My case:

Why 0x000000cb appears only on one PC, other pc's were connecting to that same printer just fine.

That error means “The driver being installed is not valid” (basically, Windows can’t load the print driver package).

On the problematic PC, Windows sees a different version of the driver already present locally (newer or incompatible). When it tries to reconcile that with the one offered by the server, the mismatch causes the installation to fail → hence 0x000000cb.

The fix that worked for me after i tried all the listed fixes:

Pre-install the exact driver locally

Since the other PCs accept the server’s older driver, you can pre-stage it on the broken PC:

Copy the working .inf driver package from another PC:
- Run pnputil /enum-drivers | findstr /i citizen on a working PC → note the oemXX.inf.
- Copy that driver folder from C:\Windows\System32\DriverStore\FileRepository\...

On the broken PC:


pnputil /add-driver <path-to-inf> /install

Then connect to the printer again → it won’t need to pull the package from the server, it’ll just match it.

Sunday, February 16, 2025

Boot Linux installations from WDS PXE

Download syslinux from http://www.kernel.org/pub/linux/utils/boot/syslinux/
Extract bios\core\pxelinux.0 bios\com32\menu\vesamenu.c32 and bios\com32\chain\chain.c32 from the syslinux download and put it on your WDS server in $WDS-ROOT\Boot\x64\(substitute WDS-ROOT for where your WDS root folder is)
Extract additional modules such as bios\com32\lib\ldlinux.c32, bios\com32\lib\libcom32.c32 , bios\com32\cmenu\libmenu\libmenu.c32, bios\com32\libutil\libutil.c32, bios\com32\lua\src\liblua.c32, bios\com32\gpllib\libgpl.c32. See also ELF missing dependencies
Rename/copy pxelinux.0 to pxelinux.com, abortpxe.com to abortpxe.0 and pxeboot.n12 to pxeboot.0
Create a folder named pxelinux.cfg in the $WDS-ROOT\Boot\x64\ folder
Create a folder named Linux (in the $WDS-ROOT\Boot\x86\ and $WDS-ROOT\Boot\x64\ folder)
Run in cmd

wdsutil /set-server /bootprogram:boot\x64\pxelinux.com /architecture:x64
wdsutil /set-server /N12bootprogram:boot\x64\pxelinux.com /architecture:x64

Will use NFS for serving the installation files

Install NFS, create and share folder $WDS-ROOT\Boot\x64\Linux
Copy your linux distro installation files (in my case ubuntu 24.04) to this folder (create Linux\ubuntu24 folder). I tried before the same with Ubuntu 22.10 but i couldn't make it to boot successfully - an error "no media filesystem found" or something like that.
Create default file in the pxelinux.cfg folder:

DEFAULT      vesamenu.c32
PROMPT       0
MENU TITLE PXE Boot Menu
MENU INCLUDE pxelinux.cfg/graphics.conf
MENU AUTOBOOT Starting Local System in 8 seconds
# Option 1 - Exit PXE Linux & boot normally
LABEL bootlocal
      menu label ^Boot Normally
      menu default
      localboot 0
      timeout 80
      TOTALTIMEOUT 9000
# Option 2 - Run WDS
LABEL WDS (WORKING)
	 MENU LABEL ^Windows Deployment Services
	 KERNEL pxeboot.0
   #-- 
Label UBUNTU
menu label Ubuntu 24.04 Install NFS
kernel /Linux/ubuntu24/casper/vmlinuz
append nfsroot=10.0.0.240:/Linux/ubuntu24 netboot=nfs ip=dhcp boot=casper initrd=/Linux/ubuntu24/casper/initrd
# Option 3 - Exit PXE Linux
LABEL Abort
	MENU LABEL E^xit
	KERNEL abortpxe.0