Local network CUPS errors


If you are failing to connect to a local CUPS server and seeing something like this:

400 Bad Request

You probably just need to add this to the main section of your /etc/cups/cupsd.conf file --

ServerAlias *

That tells the CUPS http server to ignore what host name the "remote" system is using for the CUPS server.

Don't forget to restart CUPS after you change the file.

HP Network Printer: Scanning and memory cards, under Linux


HP printers like the Color Laserjet 2840 include a scan feature, which HP only supports on Windows. However, it's possible to get all the functionality going on Linux, following the instructions in this article by Dag Rende.

You can also access the memory card slot(s) on the front of the printer. Note that memory cards in these slots are pretty much Read-Only; you can't even delete or rename files.

  1. On Ubuntu or Debian, first be sure you have the smbfs package:

    sudo apt-get install smbfs  
  2. Create a mount point:

    sudo mkdir /media/HP  
  3. Then, assuming your printer is at --

    mount -t smbfs // /media/HP  

Theoretically you should be able to use Nautilus and just connect to that "Windows" (CIFS / Samba) share, but I wasn't able to get it to pass "no username and no password" ...

.htaccess not regarded on Debian by default


I set up a Debian server and was befuddled for some time about why my .htaccess in the default server was not being obeyed. This was a Virtualmin install, but It turns out to have nothing to do with Virtualmin and everything to do with Debian's more-secure-by-default configuration.

To enable .htaccess processing in the default server, use your favorite text editor on /etc/apache2/sites-available/default (on some other distributions this may be /etc/apache2/sites-available/000-default ) and right at the top you will see:

<VirtualHost *:80>
 ServerAdmin webmaster@localhost

 DocumentRoot /var/www
 <Directory />
 Options FollowSymLinks
 AllowOverride None
 <Directory /var/www/>
 Options Indexes FollowSymLinks MultiViews
 AllowOverride None
 Order allow,deny
 allow from all

Change the two instances of AllowOverride None to AllowOverride All ...and all should be well.

With Webmin you can also go to Servers: Apache Webserver: Global Configuration: Edit Config Files; and select the sites-available/default for editing right in your browser.

Blue Griffon HTML editor


Blue Griffon seems to be the descendant of the moribund NVU and Kompozer projects, offering a What you see is what you get (WYSIWYG) HTML editing environment. Worth a look.

Linux 3.0 will have full Xen (dom0) support


Main article and discussion on Slashdot with a pertinent comment by pasikarkkainen (925729) (#36329284):

Xen is a secure baremetal hypervisor (xen.gz), around 2 MB in size, and it's the first thing that boots on your computer from GRUB. After Xen hypervisor has started it boots the "management console" VM, called "Xen dom0", which is most often Linux, but it could also be BSD or Solaris. Upstream Linux kernel v3.0 can run as Xen dom0 without additional patches. Xen dom0 has some special privileges, like direct access to hardware, so you can run device drivers in dom0 (=use native Linux kernel device drivers for disk/net etc), and dom0 then provides virtual networks and virtual disks for other VMs through Xen hypervisor. Xen also has the concept of "driver domains", where you can dedicate a piece of hardware to some VM (with Xen PCI passthru), and run the driver for the hardware in the VM, instead of dom0, adding further separation and security to the system. Xen "Driver domain" VMs can provide virtual network and virtual disk backends for other VMs. KVM on the other hand is a loadable module for Linux kernel, which turns Linux kernel into a hypervisor. The difference is that in KVM all the processes (sshd, apache, etc) running on the host Linux and the VMs share the same memory address space. So KVM has less separation between the host and the VMs, by design. VMs in KVM are processes on the host Linux, not "true" separated VMs.