Improve documentation about installation via pxe

doc/install_pxe.md

@@ -3,14 +3,27 @@
 * **Using DigitalSouveraeneSchule repository and LinuxMuster.Net tftp**  
   Simplest solution. Playbook and default inventory from DigitalSouveraeneSchule codeberg repository.  
   Linux kernel and initial Ramdisk from debian repository.  
+  Client must have access to the internet (noproxy group).
 * **Using your own repository and LinuxMuster.Net tftp**  
   Here you can use your own inventory and make many custom settings.  
   Linux kernel and initial Ramdisk from debian repository.  
+  Client must have access to the internet (noproxy group).
 * **Using your own repository and livebox tftp**  
   Additional kernel and Ramdisk from your own infrastrukture.  
+  Client does not need direct internet access.
 
 ## Using codeberg repository and LinuxMuster.Net tftp
 
+### Requirements / firewall settings
+
+The computer on which the linuxclient is to be installed must have access to the Internet (add host to noproxy group)
+
+The following resources are downloaded from the internet:
+
+* The repository is provided by codeberg.org
+* the Linux kernel, the initial ramdisk and the installation files are loaded from debian.org.
+* mscorefonts from Microsoft
+
 ### Modification LinuxMuster.Net server
 
 Create grub config for device group `lmnclient` on your schools server:
@@ -50,4 +63,52 @@ classroom;mypc01;lmnclient;F2:81:6B:C9:E3:EF;10.0.5.51;;;;classroom-studentcompu
 * confirm `hostname` and `domain` (you will be asked in network setup)
 * ... Get a cup of coffee ... wait until reboot ... login (Logging in may take a few minutes after installation)
 
-## Using your own livebox server
+
+## Using your own repository and LinuxMuster.Net tftp
+
+If you fork the lmn-client repository, you can customize the preseeding and inventory to your needs.
+Use the instructions in the previous section and customize the repository in `/srv/linbo/boot/grub/lmnclient.cfg`.
+
+It makes sense to encrypt your inventory via `ansible-vault`.
+When using encrypted inventories you have to provide the vault password by commenting in the two lines in the `/srv/linbo/boot/grub/lmnclient.cfg`.
+
+## Using your own repository and livebox tftp
+
+The next improvement will be to use your own livebox with following functionalities:
+
+* Providing linux kernel and initial ramdisk for installer
+* Can be used as cache for debian packages (aptcacher)
+* Can provide mscorefonts and libdvdcss (multimedia codecs)
+* Can be used to boot live systems (netboot) via pxe
+
+### Installing the livebox server
+
+* Install debian VM and configure network
+* Install additional packages: ansible  
+  `sudo apt install ansible`
+* Run livebox playbook  
+  `ansible-pull -i localhost, --url=https://salsa.debian.org/andi/debian-lan-ansible.git -C master livebox.yml`
+* Set DNS entry for your new livebox server
+
+### Modification LinuxMuster.Net server
+
+The file `/srv/linbo/boot/grub/lmnclient.cfg` might look like this:
+
+```
+# ### NOT managed by linuxmuster.net ###
+
+# edit to your needs
+set default=1
+
+menuentry 'Installer Debian bookworm (amd64) + preseed + ansible inventory' {
+   echo -n "Enter domain join password: "
+   read adpw
+   set vaultpw="dummy"
+   # echo -n "Enter vault password"
+   # read vaultpw
+   linux   (http,livebox.example.com)/d-i/n-pkg/images/12/amd64/text/debian-installer/amd64/linux auto=true priority=high \
+           url=https://codeberg.org/MySchool/lmn-client/raw/branch/fvs/misc/preseed-myschool.cfg interface=auto \
+           playbook=lmn-client.yml adpw="${adpw}" vaultpw="${vaultpw}" ---
+   initrd  (http,livebox.example.com)/d-i/n-pkg/images/12/amd64/text/debian-installer/amd64/initrd.gz
+}
+```