+ <title>Idea for storing LTSP configuration in LDAP</title>
+ <link>http://people.skolelinux.org/pere/blog/Idea_for_storing_LTSP_configuration_in_LDAP.html</link>
+ <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/Idea_for_storing_LTSP_configuration_in_LDAP.html</guid>
+ <pubDate>Sun, 11 Jul 2010 22:00:00 +0200</pubDate>
+ <description><p>Vagrant mentioned on IRC today that ltsp_config now support
+sourcing files from /usr/share/ltsp/ltsp_config.d/ on the thin
+clients, and that this can be used to fetch configuration from LDAP if
+Debian Edu choose to store configuration there.</p>
+
+<p>Armed with this information, I got inspired and wrote a test module
+to get configuration from LDAP. The idea is to look up the MAC
+address of the client in LDAP, and look for attributes on the form
+ltspconfigsetting=value, and use this to export SETTING=value to the
+LTSP clients.</p>
+
+<p>The goal is to be able to store the LTSP configuration attributes
+in a "computer" LDAP object used by both DNS and DHCP, and thus
+allowing us to store all information about a computer in one place.</p>
+
+<p>This is a untested draft implementation, and I welcome feedback on
+this approach. A real LDAP schema for the ltspClientAux objectclass
+need to be written. Comments, suggestions, etc?</p>
+
+<blockquote><pre>
+# Store in /opt/ltsp/$arch/usr/share/ltsp/ltsp_config.d/ldap-config
+#
+# Fetch LTSP client settings from LDAP based on MAC address
+#
+# Uses ethernet address as stored in the dhcpHost objectclass using
+# the dhcpHWAddress attribute or ethernet address stored in the
+# ieee802Device objectclass with the macAddress attribute.
+#
+# This module is written to be schema agnostic, and only depend on the
+# existence of attribute names.
+#
+# The LTSP configuration variables are saved directly using a
+# ltspConfig prefix and uppercasing the rest of the attribute name.
+# To set the SERVER variable, set the ltspConfigServer attribute.
+#
+# Some LDAP schema should be created with all the relevant
+# configuration settings. Something like this should work:
+#
+# objectclass ( 1.1.2.2 NAME 'ltspClientAux'
+# SUP top
+# AUXILIARY
+# MAY ( ltspConfigServer $ ltsConfigSound $ ... )
+
+LDAPSERVER=$(debian-edu-ldapserver)
+if [ "$LDAPSERVER" ] ; then
+ LDAPBASE=$(debian-edu-ldapserver -b)
+ for MAC in $(LANG=C ifconfig |grep -i hwaddr| awk '{print $5}'|sort -u) ; do
+ filter="(|(dhcpHWAddress=ethernet $MAC)(macAddress=$MAC))"
+ ldapsearch -h "$LDAPSERVER" -b "$LDAPBASE" -v -x "$filter" | \
+ grep '^ltspConfig' | while read attr value ; do
+ # Remove prefix and convert to upper case
+ attr=$(echo $attr | sed 's/^ltspConfig//i' | tr a-z A-Z)
+ # bass value on to clients
+ eval "$attr=$value; export $attr"
+ done
+ done
+fi
+</pre></blockquote>
+
+<p>I'm not sure this shell construction will work, because I suspect
+the while block might end up in a subshell causing the variables set
+there to not show up in ltsp-config, but if that is the case I am sure
+the code can be restructured to make sure the variables are passed on.
+I expect that can be solved with some testing. :)</p>
+
+<p>If you want to help out with implementing this for Debian Edu,
+please contact us on debian-edu@lists.debian.org.</p>
+
+<p>Update 2010-07-17: I am aware of another effort to store LTSP
+configuration in LDAP that was created around year 2000 by
+<a href="http://www.pcxperience.com/thinclient/documentation/ldap.html">PC
+Xperience, Inc., 2000</a>. I found its
+<a href="http://people.redhat.com/alikins/ltsp/ldap/">files</a> on a
+personal home page over at redhat.com.</p>
+</description>
+ </item>
+
+ <item>
+ <title>jXplorer, a very nice LDAP GUI</title>
+ <link>http://people.skolelinux.org/pere/blog/jXplorer__a_very_nice_LDAP_GUI.html</link>
+ <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/jXplorer__a_very_nice_LDAP_GUI.html</guid>
+ <pubDate>Fri, 9 Jul 2010 12:55:00 +0200</pubDate>
+ <description><p>Since
+<a href="http://people.skolelinux.org/pere/blog/LUMA__a_very_nice_LDAP_GUI.html">my
+last post</a> about available LDAP tools in Debian, I was told about a
+LDAP GUI that is even better than luma. The java application
+<a href="http://jxplorer.org/">jXplorer</a> is claimed to be capable of
+moving LDAP objects and subtrees using drag-and-drop, and can
+authenticate using Kerberos. I have only tested the Kerberos
+authentication, but do not have a LDAP setup allowing me to rewrite
+LDAP with my test user yet. It is
+<a href="http://packages.qa.debian.org/j/jxplorer.html">available in
+Debian</a> testing and unstable at the moment. The only problem I
+have with it is how it handle errors. If something go wrong, its
+non-intuitive behaviour require me to go through some query work list
+and remove the failing query. Nothing big, but very annoying.</p>
+</description>
+ </item>
+
+ <item>
+ <title>MS Word krøller det til for politiet?</title>
+ <link>http://people.skolelinux.org/pere/blog/MS_Word_kr_ller_det_til_for_politiet_.html</link>
+ <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/MS_Word_kr_ller_det_til_for_politiet_.html</guid>
+ <pubDate>Thu, 8 Jul 2010 14:00:00 +0200</pubDate>
+ <description><p>De siste dagene har Aftenposten
+<a href="http://www.aftenposten.no/nyheter/iriks/article3718597.ece">fortalt</a>
+<a href="http://www.aftenposten.no/nyheter/iriks/article3724249.ece">hvordan</a>
+politet har brukt skriveverktøy som ikke håndterer arabisk tekst og
+tekst som skal skrives fra høyre mot venstre når de har laget
+løpeseddel for å be om informasjon fra publikum. Resultatet har vært
+en uleselig arabisk-bit på løpeseddelen. Feilen har oppstått når
+teksten har blitt "kopiert inn i programvare som ikke har støtte for
+språk som skrives fra høyre mot venstre", og jeg er ganske sikker på
+at det er snakk om Microsoft Office i dette tilfellet. Er det slik at
+MS Office i norsk språkdrakt ikke har støtte for tekst som skal
+skrives fra høyre mot venstre? Jeg tror alle utgaver av
+OpenOffice.org har slik støtte, og det er jo ikke veldig vanskelig å
+la slik støtte finnes i alle utgaver av et program hvis støtten først
+er utviklet. Aftenpostens melding får meg til å undre om problemet
+ville vært unngått hvis politiet brukte OpenOffice.org i stedet for MS
+Office.</p>
+
+<p>Mon tro om det er flere eksempler på at MS Office har ødelagt for
+offentlig myndighet?</p>
+</description>
+ </item>
+
+ <item>
+ <title>Lenny->Squeeze upgrades, apt vs aptitude with the Gnome desktop</title>
+ <link>http://people.skolelinux.org/pere/blog/Lenny__Squeeze_upgrades__apt_vs_aptitude_with_the_Gnome_desktop.html</link>
+ <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/Lenny__Squeeze_upgrades__apt_vs_aptitude_with_the_Gnome_desktop.html</guid>
+ <pubDate>Sat, 3 Jul 2010 23:55:00 +0200</pubDate>
+ <description><p>Here is a short update on my <a
+href="http://people.skolelinux.org/~pere/debian-upgrade-testing/">my
+Debian Lenny->Squeeze upgrade testing</a>. Here is a summary of the
+difference for Gnome when it is upgraded by apt-get and aptitude. I'm
+not reporting the status for KDE, because the upgrade crashes when
+aptitude try because of missing conflicts
+(<a href="http://bugs.debian.org/584861">#584861</a> and
+<a href="http://bugs.debian.org/585716">#585716</a>).</p>
+
+<p>At the end of the upgrade test script, dpkg -l is executed to get a
+complete list of the installed packages. Based on this I see these
+differences when I did a test run today. As usual, I do not really
+know what the correct set of packages would be, but thought it best to
+publish the difference.</p>
+
+<p>Installed using apt-get, missing with aptitude</p>
+
+<blockquote><p>
+ at-spi cpp-4.3 finger gnome-spell gstreamer0.10-gnomevfs
+ libatspi1.0-0 libcupsys2 libeel2-data libgail-common libgdl-1-common
+ libgnomeprint2.2-data libgnomeprintui2.2-common libgnomevfs2-bin
+ libgtksourceview-common libpt-1.10.10-plugins-alsa
+ libpt-1.10.10-plugins-v4l libservlet2.4-java libxalan2-java
+ libxerces2-java openoffice.org-writer2latex openssl-blacklist p7zip
+ python-4suite-xml python-eggtrayicon python-gtkhtml2
+ python-gtkmozembed svgalibg1 xserver-xephyr zip
+</p></blockquote>
+
+<p>Installed using apt-get, removed with aptitude</p>
+
+<blockquote><p>
+ bluez-utils dhcdbd djvulibre-desktop epiphany-gecko
+ gnome-app-install gnome-mount gnome-vfs-obexftp gnome-volume-manager
+ libao2 libavahi-compat-libdnssd1 libavahi-core5 libbind9-50
+ libbluetooth2 libcamel1.2-11 libcdio7 libcucul0 libcurl3
+ libdirectfb-1.0-0 libdvdread3 libedata-cal1.2-6 libedataserver1.2-9
+ libeel2-2.20 libepc-1.0-1 libepc-ui-1.0-1 libexchange-storage1.2-3
+ libfaad0 libgd2-noxpm libgda3-3 libgda3-common libggz2 libggzcore9
+ libggzmod4 libgksu1.2-0 libgksuui1.0-1 libgmyth0 libgnome-desktop-2
+ libgnome-pilot2 libgnomecups1.0-1 libgnomeprint2.2-0
+ libgnomeprintui2.2-0 libgpod3 libgraphviz4 libgtkhtml2-0
+ libgtksourceview1.0-0 libgucharmap6 libhesiod0 libicu38 libisccc50
+ libisccfg50 libiw29 libkpathsea4 libltdl3 liblwres50 libmagick++10
+ libmagick10 libmalaga7 libmtp7 libmysqlclient15off libnautilus-burn4
+ libneon27 libnm-glib0 libnm-util0 libopal-2.2 libosp5
+ libparted1.8-10 libpisock9 libpisync1 libpoppler-glib3 libpoppler3
+ libpt-1.10.10 libraw1394-8 libsensors3 libsmbios2 libsoup2.2-8
+ libssh2-1 libsuitesparse-3.1.0 libswfdec-0.6-90 libtalloc1
+ libtotem-plparser10 libtrackerclient0 libvoikko1 libxalan2-java-gcj
+ libxerces2-java-gcj libxklavier12 libxtrap6 libxxf86misc1 libzephyr3
+ mysql-common swfdec-gnome totem-gstreamer wodim
+</p></blockquote>
+
+<p>Installed using aptitude, missing with apt-get</p>
+
+<blockquote><p>
+ gnome gnome-desktop-environment hamster-applet python-gnomeapplet
+ python-gnomekeyring python-wnck rhythmbox-plugins xorg
+ xserver-xorg-input-all xserver-xorg-input-evdev
+ xserver-xorg-input-kbd xserver-xorg-input-mouse
+ xserver-xorg-input-synaptics xserver-xorg-video-all
+ xserver-xorg-video-apm xserver-xorg-video-ark xserver-xorg-video-ati
+ xserver-xorg-video-chips xserver-xorg-video-cirrus
+ xserver-xorg-video-dummy xserver-xorg-video-fbdev
+ xserver-xorg-video-glint xserver-xorg-video-i128
+ xserver-xorg-video-i740 xserver-xorg-video-mach64
+ xserver-xorg-video-mga xserver-xorg-video-neomagic
+ xserver-xorg-video-nouveau xserver-xorg-video-nv
+ xserver-xorg-video-r128 xserver-xorg-video-radeon
+ xserver-xorg-video-radeonhd xserver-xorg-video-rendition
+ xserver-xorg-video-s3 xserver-xorg-video-s3virge
+ xserver-xorg-video-savage xserver-xorg-video-siliconmotion
+ xserver-xorg-video-sis xserver-xorg-video-sisusb
+ xserver-xorg-video-tdfx xserver-xorg-video-tga
+ xserver-xorg-video-trident xserver-xorg-video-tseng
+ xserver-xorg-video-vesa xserver-xorg-video-vmware
+ xserver-xorg-video-voodoo
+</p></blockquote>
+
+<p>Installed using aptitude, removed with apt-get</p>
+
+<blockquote><p>
+ deskbar-applet xserver-xorg xserver-xorg-core
+ xserver-xorg-input-wacom xserver-xorg-video-intel
+ xserver-xorg-video-openchrome
+</p></blockquote>
+
+<p>I was told on IRC that the xorg-xserver package was
+<a href="http://git.debian.org/?p=pkg-xorg/xserver/xorg-server.git;a=commit;h=9c8080d06c457932d3bfec021c69ac000aa60120">changed
+in git</a> today to try to get apt-get to not remove xorg completely.
+No idea when it hits Squeeze, but when it does I hope it will reduce
+the difference somewhat.
+</description>
+ </item>
+
+ <item>
+ <title>Caching password, user and group on a roaming Debian laptop</title>
+ <link>http://people.skolelinux.org/pere/blog/Caching_password__user_and_group_on_a_roaming_Debian_laptop.html</link>
+ <guid isPermaLink="true">http://people.skolelinux.org/pere/blog/Caching_password__user_and_group_on_a_roaming_Debian_laptop.html</guid>
+ <pubDate>Thu, 1 Jul 2010 11:40:00 +0200</pubDate>
+ <description><p>For a laptop, centralized user directories and password checking is
+a bit troubling. Laptops are typically used also when not connected
+to the network, and it is vital for a user to be able to log in or
+unlock the screen saver also when a central server is unavailable.
+This is possible by caching passwords and directory information (user
+and group attributes) locally, and the packages to do so are available
+in Debian. Here follow two recipes to set this up in Debian/Squeeze.
+It is also possible to set up in Debian/Lenny, but require more manual
+setup there because pam-auth-update is missing in Lenny.</p>
+
+<h2>LDAP/Kerberos + nscd + libpam-ccreds + libpam-mklocaluser/pam_mkhomedir</h2>
+
+This is the traditional method with a twist. The password caching is
+provided by libpam-ccreds (version 10-4 or later is needed on
+Squeeze), and the directory caching is done by nscd. The directory
+lookup and password checking is done using LDAP. If one want to use
+Kerberos for password checking the libpam-ldapd package can be
+replaced with libpam-krb5 or libpam-heimdal. If one is happy having a
+local home directory with the path listed in LDAP, one can use the
+pam_mkhomedir module from pam-modules to make this happen instead of
+using libpam-mklocaluser. A setup for pam-auth-update to enable
+pam_mkhomedir will have to be written until a fix for
+<a href="http://bugs.debian.org/568577">bug #568577</a> is in the
+archive. Because I believe it is a bad idea to have local home
+directories using misleading paths like /site/server/partition/, I
+prefer to create a local user with the home directory in /home/. This
+is done using the libpam-mklocaluser package.</p>
+
+<p>These packages need to be installed and configured</p>
+
+<blockquote><pre>
+libnss-ldapd libpam-ldapd nscd libpam-ccreds libpam-mklocaluser
+</pre></blockquote>
+
+<p>The ldapd packages will ask for LDAP connection information, and
+one have to fill in the values that fits ones own site. Make sure the
+PAM part uses encrypted connections, to make sure the password is not
+sent in clear text to the LDAP server. I've been unable to get TLS
+certificate checking for a self signed certificate working, which make
+LDAP authentication unsafe for Debian Edu (nslcd is not checking if it
+is talking to the correct LDAP server), and very much welcome feedback
+on how to get this working.</p>
+
+<p>Because nscd do not have a default configuration fit for offline
+caching until <a href="http://bugs.debian.org/485282">bug #485282</a>
+is fixed, this configuration should be used instead of the one
+currently in /etc/nscd.conf. The changes are in the fields
+reload-count and positive-time-to-live, and is based on the
+instructions I found in the
+<a href="http://www.flyn.org/laptopldap/">LDAP for Mobile Laptops</a>
+instructions by Flyn Computing.</p>
+
+<blockquote><pre>
+ debug-level 0
+ reload-count unlimited
+ paranoia no
+
+ enable-cache passwd yes
+ positive-time-to-live passwd 2592000
+ negative-time-to-live passwd 20
+ suggested-size passwd 211
+ check-files passwd yes
+ persistent passwd yes
+ shared passwd yes
+ max-db-size passwd 33554432
+ auto-propagate passwd yes
+
+ enable-cache group yes
+ positive-time-to-live group 2592000
+ negative-time-to-live group 20
+ suggested-size group 211
+ check-files group yes
+ persistent group yes
+ shared group yes
+ max-db-size group 33554432
+ auto-propagate group yes
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