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   5   <title>Petter Reinholdtsen</title>
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  13   <h1>
  14        <a href="http://people.skolelinux.org/pere/blog/">Petter Reinholdtsen</a>
  15
  16   </h1>
  17
  18  </div>
  19
  20
  21
  22  <div class="entry">
  23   <div class="title"><a href="http://people.skolelinux.org/pere/blog/Debian_Edu_roaming_workstation___at_the_university_of_Oslo.html">Debian Edu roaming workstation - at the university of Oslo</a></div>
  24   <div class="date">2010-08-03 23:30</div>
  25   <div class="body">
  26 <p>The new roaming workstation profile in Debian Edu/Squeeze is fairly
  27 similar to the laptop setup am I working on using Ubuntu for the
  28 University of Oslo, and just for the heck of it, I tested today how
  29 hard it would be to integrate that profile into the university
  30 infrastructure.  In this case, it is the university LDAP server,
  31 Active Directory Kerberos server and SMB mounting from the Netapp file
  32 servers.</p>
  33
  34 <p>I was pleasantly surprised that the only three files needed to be
  35 changed (/etc/sssd/sssd.conf, /etc/ldap.conf and
  36 /etc/mklocaluser.d/20-debian-edu-config) and one file had to be added
  37 (/usr/share/perl5/Debian/Edu_Local.pm), to get the client working.
  38 Most of the changes were to get the client to use the university LDAP
  39 for NSS and Kerberos server for PAM, but one was to change a hard
  40 coded DNS domain name in the mklocaluser hook from .intern to
  41 .uio.no.</p>
  42
  43 <p>This testing was so encouraging, that I went ahead and adjusted the
  44 Debian Edu scripts and setup in subversion to centralise the roaming
  45 workstation setup a bit more and avoid the hardcoded DNS domain name,
  46 so that when I test this tomorrow, I expect to get away with modifying
  47 only /etc/sssd/sssd.conf and /etc/ldap.conf to get it to use the
  48 university servers.</p>
  49
  50 <p>My goal is to get the clients to have no hardcoded settings and
  51 fetch all their initial setup during installation and first boot, to
  52 allow them to be inserted also into environments where the default
  53 setup in Debian Edu has been changed or as with the university, where
  54 the environment is different but provides the protocols Debian Edu
  55 uses.</p>
  56 </div>
  57   <div class="tags">
  58
  59
  60
  61    Tags: <a href="http://people.skolelinux.org/pere/blog/tags/debian edu">debian edu</a>, <a href="http://people.skolelinux.org/pere/blog/tags/english">english</a>, <a href="http://people.skolelinux.org/pere/blog/tags/nuug">nuug</a>.
  62
  63   </div>
  64  </div>
  65  <div class="padding"></div>
  66
  67  <div class="entry">
  68   <div class="title"><a href="http://people.skolelinux.org/pere/blog/Circular_package_dependencies_harms_apt_recovery.html">Circular package dependencies harms apt recovery</a></div>
  69   <div class="date">2010-07-27 23:50</div>
  70   <div class="body">
  71 <p>I discovered this while doing
  72 <a href="http://people.skolelinux.org/pere/blog/Automatic_upgrade_testing_from_Lenny_to_Squeeze.html">automated
  73 testing of upgrades from Debian Lenny to Squeeze</a>.  A few packages
  74 in Debian still got circular dependencies, and it is often claimed
  75 that apt and aptitude should be able to handle this just fine, but
  76 some times these dependency loops causes apt to fail.</p>
  77
  78 <p>An example is from todays
  79 <a href="http://people.skolelinux.org/~pere/debian-upgrade-testing//test-20100727-lenny-squeeze-kde-aptitude.txt">upgrade
  80 of KDE using aptitude</a>.  In it, a bug in kdebase-workspace-data
  81 causes perl-modules to fail to upgrade.  The cause is simple.  If a
  82 package fail to unpack, then only part of packages with the circular
  83 dependency might end up being unpacked when unpacking aborts, and the
  84 ones already unpacked will fail to configure in the recovery phase
  85 because its dependencies are unavailable.</p>
  86
  87 <p>In this log, the problem manifest itself with this error:</p>
  88
  89 <blockquote><pre>
  90 dpkg: dependency problems prevent configuration of perl-modules:
  91  perl-modules depends on perl (>= 5.10.1-1); however:
  92   Version of perl on system is 5.10.0-19lenny2.
  93 dpkg: error processing perl-modules (--configure):
  94  dependency problems - leaving unconfigured
  95 </pre></blockquote>
  96
  97 <p>The perl/perl-modules circular dependency is already
  98 <a href="http://bugs.debian.org/527917">reported as a bug</a>, and will
  99 hopefully be solved as soon as possible, but it is not the only one,
 100 and each one of these loops in the dependency tree can cause similar
 101 failures.  Of course, they only occur when there are bugs in other
 102 packages causing the unpacking to fail, but it is rather nasty when
 103 the failure of one package causes the problem to become worse because
 104 of dependency loops.</p>
 105
 106 <p>Thanks to
 107 <a href="http://lists.debian.org/debian-devel/2010/06/msg00116.html">the
 108 tireless effort by Bill Allombert</a>, the number of circular
 109 dependencies
 110 <a href="http://debian.semistable.com/debgraph.out.html">left in Debian
 111 is dropping</a>, and perhaps it will reach zero one day. :)</p>
 112
 113 <p>Todays testing also exposed a bug in
 114 <a href="http://bugs.debian.org/590605">update-notifier</a> and
 115 <a href="http://bugs.debian.org/590604">different behaviour</a> between
 116 apt-get and aptitude, the latter possibly caused by some circular
 117 dependency.  Reported both to BTS to try to get someone to look at
 118 it.</p>
 119 </div>
 120   <div class="tags">
 121
 122
 123
 124    Tags: <a href="http://people.skolelinux.org/pere/blog/tags/debian">debian</a>, <a href="http://people.skolelinux.org/pere/blog/tags/english">english</a>, <a href="http://people.skolelinux.org/pere/blog/tags/nuug">nuug</a>.
 125
 126   </div>
 127  </div>
 128  <div class="padding"></div>
 129
 130  <div class="entry">
 131   <div class="title"><a href="http://people.skolelinux.org/pere/blog/First_Debian_Edu_test_release__alpha0__based_on_Squeeze_is_released.html">First Debian Edu test release (alpha0) based on Squeeze is released</a></div>
 132   <div class="date">2010-07-27 17:45</div>
 133   <div class="body">
 134 <p>I just posted this announcement culminating several months of work
 135 with the next Debian Edu release.  Not nearly done, but one major step
 136 completed.</p>
 137
 138 <blockquote>
 139 <p>This is the first test release based on Squeeze. The focus of this
 140 release is to test the user application selection. To have a look,
 141 install the standalone profile and let the developers know if the set
 142 of installed packages i.e. applications should be modified. If some
 143 user application is missing, or if there are some applications that no
 144 longer make sense to be included in Debian Edu, please let us know.
 145 Also, if a useful application is missing the translation for your
 146 language of choice, please let us know too.</p>
 147
 148 <p>In addition, feedback and help to polish the desktop (menus,
 149 artwork, starters, etc.) is appreciated. We would like to ship a nice
 150 and handy KDE4 desktop targeted for schools out of the box.</p>
 151
 152 <p>The other profiles should be installable, but there is a lot more
 153 work left to be done before they are ready, so do not expect to
 154 much.</p>
 155
 156 <p>Changes compared to the lenny based version</p>
 157
 158 <ul>
 159 <li>Everything from Debian Squeeze
 160 <ul>
 161   <li>Desktop environment KDE 4.4 => the new KDE desktop in
 162          combination with some new artwork
 163   <li>Web browser Iceweasel 3.5
 164   <li>OpenOffice.org 3.2
 165   <li>Educational toolbox GCompris 9.3
 166   <li>Music creator Rosegarden 10.04.2
 167   <li>Image editor Gimp 2.6.10
 168   <li>Virtual universe Celestia 1.6.0
 169   <li>Virtual stargazer Stellarium 0.10.4
 170   <li>3D modeler Blender 2.49.2 (new application)
 171   <li>Video editor Kdenlive 0.7.7 (new application)
 172 </ul></li>
 173 <li>Now using Kerberos for password checking (migration not finished).
 174     Enabled for:
 175 <ul>
 176   <li>PAM
 177   <li>LDAP
 178   <li>IMAP
 179   <li>SMTP (sender verification)
 180 </ul>
 181 </li>
 182 <li>New experimental roaming workstation profile for laptops.</li>
 183 <li>Show welcome page to users when they first log in. The URL is
 184     fetched from LDAP.</li>
 185 <li>New LXDE desktop option, in addition to KDE (default) and Gnome.</li>
 186 <li>General cleanup (not finished)</li>
 187 </ul>
 188 <p>The following features are not working as they should</p>
 189
 190 <ul>
 191 <li>No web based administration tool for creating users and groups. The
 192     scripts ldap-createuser-krb and ldap-add-user-to-group can be used
 193     for testing.</li>
 194 <li>DVD installs are missing debian-installer images for the PXE boot,
 195     and do not set up the PXE menu on eth0 because of this. LTSP
 196     clients should still boot from eth1 on thin client servers.</li>
 197 <li>The restructured KDE menu is not implemented.</li>
 198 <li>The LDAP server setup need to be reviewed for security.</li>
 199 <li>The LDAP directory structure need to be reworked.</li>
 200 <li>Different sets of packages are installed when using the DVD and the
 201     netinst CD. More packages are installed using the netinst CD.</li>
 202 <li>The jackd package fail to install. This is believed to be caused by
 203     some ongoing transition, and hopefully should be solved soon. The
 204     jackd1 package can be installed manually for those that need it.</li>
 205 <li>Some packages lack translations. See
 206     http://wiki.debian.org/DebianEdu/Status/Squeeze for updated status,
 207     and help out with translations.</li>
 208 </ul>
 209
 210 <p>To download this multiarch netinstall release you can use</p>
 211
 212 <ul>
 213 <li><a href="ftp://ftp.skolelinux.org/skolelinux-cd/squeeze-alpha/debian-edu-6.0.0+edua0-CD.iso">ftp://ftp.skolelinux.org/skolelinux-cd/squeeze-alpha/debian-edu-6.0.0+edua0-CD.iso</a></li>
 214 <li><a href="http://ftp.skolelinux.org/skolelinux-cd/squeeze-alpha/debian-edu-6.0.0+edua0-CD.iso">http://ftp.skolelinux.org/skolelinux-cd/squeeze-alpha/debian-edu-6.0.0+edua0-CD.iso</a></li>
 215 <li>rsync -avzP ftp.skolelinux.org::skolelinux-cd/squeeze-alpha/debian-edu-6.0.0+edua0-CD.iso</li>
 216 </ul>
 217 <p>To download this multiarch dvd release you can use</p>
 218
 219 <ul>
 220 <li><a href="ftp://ftp.skolelinux.org/skolelinux-cd/squeeze-alpha/debian-edu-6.0.0+edua0-DVD.iso">ftp://ftp.skolelinux.org/skolelinux-cd/squeeze-alpha/debian-edu-6.0.0+edua0-DVD.iso</a></li>
 221 <li><a href="http://ftp.skolelinux.org/skolelinux-cd/squeeze-alpha/debian-edu-6.0.0+edua0-DVD.iso">http://ftp.skolelinux.org/skolelinux-cd/squeeze-alpha/debian-edu-6.0.0+edua0-DVD.iso</a></li>
 222 <li>rsync -avzP ftp.skolelinux.org::skolelinux-cd/squeeze-alpha/debian-edu-6.0.0+edua0-DVD.iso</li>
 223 </ul>
 224
 225 <p>There is no source DVD available yet. It will be prepared when we
 226 get closer to the final release.</p>
 227
 228 <p>The MD5SUM of these images are</p>
 229
 230 <ul>
 231 <li>3dbf45d59f42a53518b6e3c9ec3b5eb6 debian-edu-6.0.0+edua0-CD.iso</li>
 232 <li>22f2cbfce281d1c6e478be452638675d debian-edu-6.0.0+edua0-DVD.iso</li>
 233 </ul>
 234
 235 <p>The SHA1SUM of these images are</p>
 236 <ul>
 237 <li>c53d1b69b40cf37cd27aefaf33f6f6a3821bedf0 debian-edu-6.0.0+edua0-CD.iso</li>
 238 <li>2ec29d7db676d59d32197b05c277ffe16348376c debian-edu-6.0.0+edua0-DVD.iso</li>
 239 </ul>
 240 <p>How to report bugs:
 241 http://wiki.debian.org/DebianEdu/HowTo/ReportBugsInBugzilla</p>
 242
 243 <p>Please direct replies to debian-edu@lists.debian.org</p>
 244 </blockquote>
 245 </div>
 246   <div class="tags">
 247
 248
 249
 250    Tags: <a href="http://people.skolelinux.org/pere/blog/tags/debian edu">debian edu</a>, <a href="http://people.skolelinux.org/pere/blog/tags/english">english</a>, <a href="http://people.skolelinux.org/pere/blog/tags/nuug">nuug</a>.
 251
 252   </div>
 253  </div>
 254  <div class="padding"></div>
 255
 256  <div class="entry">
 257   <div class="title"><a href="http://people.skolelinux.org/pere/blog/One_step_closer_to_single_signon_in_Debian_Edu.html">One step closer to single signon in Debian Edu</a></div>
 258   <div class="date">2010-07-25 10:00</div>
 259   <div class="body">
 260 <p>The last few months me and the other Debian Edu developers have
 261 been working hard to get the Debian/Squeeze based version of Debian
 262 Edu/Skolelinux into shape.  This future version will use Kerberos for
 263 authentication, and services are slowly migrated to single signon,
 264 getting rid of password questions one at the time.</p>
 265
 266 <p>It will also feature a roaming workstation profile with local home
 267 directory, for laptops that are only some times on the Skolelinux
 268 network, and for this profile a shortcut is created in Gnome and KDE
 269 to gain access to the users home directory on the file server.  This
 270 shortcut uses SMB at the moment, and yesterday I had time to test if
 271 SMB mounting had started working in KDE after we added the cifs-utils
 272 package.  I was pleasantly surprised how well it worked.</p>
 273
 274 <p>Thanks to the recent changes to our samba configuration to get it
 275 to use Kerberos for authentication, there were no question about user
 276 password when mounting the SMB volume.  A simple click on the shortcut
 277 in the KDE menu, and a window with the home directory popped
 278 up. :)</p>
 279
 280 <p>One step closer to a single signon solution out of the box in
 281 Debian Edu.  We already had PAM, LDAP, IMAP and SMTP in place, and now
 282 also Samba.  Next step is Cups and hopefully also NFS.</p>
 283
 284 <p>We had planned a alpha0 release of Debian Edu for today, but thanks
 285 to the autobuilder administrators for some architectures being slow to
 286 sign packages, we are still missing the fixed LTSP package we need for
 287 the release.  It was uploaded three days ago with urgency=high, and if
 288 it had entered testing yesterday we would have been able to test it in
 289 time for a alpha0 release today.  As the binaries for ia64 and powerpc
 290 still not uploaded to the Debian archive, we need to delay the alpha
 291 release another day.</p>
 292
 293 <p>If you want to help out with implementing Kerberos for Debian Edu,
 294 please contact us on debian-edu@lists.debian.org.</p>
 295 </div>
 296   <div class="tags">
 297
 298
 299
 300    Tags: <a href="http://people.skolelinux.org/pere/blog/tags/debian edu">debian edu</a>, <a href="http://people.skolelinux.org/pere/blog/tags/english">english</a>, <a href="http://people.skolelinux.org/pere/blog/tags/nuug">nuug</a>, <a href="http://people.skolelinux.org/pere/blog/tags/sikkerhet">sikkerhet</a>.
 301
 302   </div>
 303  </div>
 304  <div class="padding"></div>
 305
 306  <div class="entry">
 307   <div class="title"><a href="http://people.skolelinux.org/pere/blog/Digitale_restriksjonsmekanismer_fikk_meg_til____slutte____kj__pe_musikk.html">Digitale restriksjonsmekanismer fikk meg til å slutte å kjøpe musikk</a></div>
 308   <div class="date">2010-07-22 23:50</div>
 309   <div class="body">
 310 <p>For mange år siden slutte jeg å kjøpe musikk-CDer. Årsaken var at
 311 musikkbransjen var godt i gang med å selge platene sine med DRM som
 312 gjorde at jeg ikke fikk spilt av musikken jeg kjøpte på utstyret jeg
 313 hadde tilgjengelig, dvs. min datamaskin. Det var umulig å se på en
 314 plate om den var ødelagt eller ikke, og jeg hadde jo allerede en
 315 anseelig samling med plater, så jeg bestemme meg for å slutte å gi
 316 penger til en bransje som åpenbart ikke respekterte meg.</p>
 317
 318 <p>Jeg har mange titalls dager med musikk på CD i dag. Det meste er
 319 lagt i et stort arkiv som kan spilles av fra husets datamaskiner (har
 320 ikke rukket rippe alt). Jeg ser dermed ikke behovet for å skaffe mer
 321 musikk. De fleste av mine favoritter er i hus, og jeg er dermed godt
 322 fornøyd.</p>
 323
 324 <p>Hvis musikkbransjen ønsker mine penger, så må de demonstrere at de
 325 setter pris på meg som kunde, og ikke skremme meg bort med DRM og
 326 antydninger om at kundene er kriminelle.</p>
 327
 328 <p>Filmbransjen er like ille, men mens musikk gjerne varer lenge, er
 329 filmer mer ferskvare. Har dermed ikke helt sluttet å kjøpe filmer, men
 330 holder meg til DVD-filmer som kan spilles av på mine Linuxbokser.
 331 Kommer neppe til å ta i bruk Blueray, og ei heller de nye DRM-greiene
 332 «Ultraviolet» som be annonsert her om dagen.</p>
 333 </div>
 334   <div class="tags">
 335
 336
 337
 338    Tags: <a href="http://people.skolelinux.org/pere/blog/tags/fildeling">fildeling</a>, <a href="http://people.skolelinux.org/pere/blog/tags/norsk">norsk</a>, <a href="http://people.skolelinux.org/pere/blog/tags/nuug">nuug</a>, <a href="http://people.skolelinux.org/pere/blog/tags/opphavsrett">opphavsrett</a>, <a href="http://people.skolelinux.org/pere/blog/tags/personvern">personvern</a>.
 339
 340   </div>
 341  </div>
 342  <div class="padding"></div>
 343
 344  <div class="entry">
 345   <div class="title"><a href="http://people.skolelinux.org/pere/blog/OpenStreetmap_one_step_closer_to_having_routing_on_its_front_page.html">OpenStreetmap one step closer to having routing on its front page</a></div>
 346   <div class="date">2010-07-18 16:45</div>
 347   <div class="body">
 348 <p>Thanks to
 349 <a href="http://feedproxy.google.com/~r/Opengeodata/~3/wUTCzDZk3lc/project-of-the-week-which-way-home">todays
 350 opengeodata blog entry</a>, I just discovered that the
 351 OpenStreetmap.org site have gotten
 352 <a href="http://nroets.dev.openstreetmap.org/demo/index.html?layers=B000FTFTT">support
 353 for calculating routes</a>.  The support is still experimental and
 354 only available from the development server, until more experience is
 355 gathered on the user interface and any scalability issues.</p>
 356
 357 <p>Earlier, the routing I knew about using the OpenStreetmap.org data
 358 was provided by <a href="http://maps.cloudmade.com/">Cloudmade</a>,
 359 but having it on the main page is required to make everyone aware of
 360 the issue.  I've had people reject Openstreetmap.org as a viable
 361 alternative for them because the front page lacked routing support,
 362 and I hope their needs will be catered for when routing show up on the
 363 www.openstreetmap.org front page.</p>
 364 </div>
 365   <div class="tags">
 366
 367
 368
 369    Tags: <a href="http://people.skolelinux.org/pere/blog/tags/english">english</a>, <a href="http://people.skolelinux.org/pere/blog/tags/kart">kart</a>, <a href="http://people.skolelinux.org/pere/blog/tags/web">web</a>.
 370
 371   </div>
 372  </div>
 373  <div class="padding"></div>
 374
 375  <div class="entry">
 376   <div class="title"><a href="http://people.skolelinux.org/pere/blog/What_are_they_searching_for___PowerDNS_and_ISC_DHCP_in_LDAP.html">What are they searching for - PowerDNS and ISC DHCP in LDAP</a></div>
 377   <div class="date">2010-07-17 21:00</div>
 378   <div class="body">
 379 <p>This is a
 380 <a href="http://people.skolelinux.org/pere/blog/Time_for_new__LDAP_schemas_replacing_RFC_2307_.html">followup</a>
 381 on my
 382 <a href="http://people.skolelinux.org/pere/blog/Idea_for_a_change_to_LDAP_schemas_allowing_DNS_and_DHCP_info_to_be_combined_into_one_object.html">previous
 383 work</a> on
 384 <a href="http://people.skolelinux.org/pere/blog/Combining_PowerDNS_and_ISC_DHCP_LDAP_objects.html">merging
 385 all</a> the computer related LDAP objects in Debian Edu.</p>
 386
 387 <p>As a step to try to see if it possible to merge the DNS and DHCP
 388 LDAP objects, I have had a look at how the packages pdns-backend-ldap
 389 and dhcp3-server-ldap in Debian use the LDAP server.  The two
 390 implementations are quite different in how they use LDAP.</p>
 391
 392 To get this information, I started slapd with debugging enabled and
 393 dumped the debug output to a file to get the LDAP searches performed
 394 on a Debian Edu main-server.  Here is a summary.
 395
 396 <p><strong>powerdns</strong></p>
 397
 398 <a href="http://www.linuxnetworks.de/doc/index.php/PowerDNS_LDAP_Backend">Clues
 399 on how to</a> set up PowerDNS to use a LDAP backend is available on
 400 the web.
 401
 402 <p>PowerDNS have two modes of operation using LDAP as its backend.
 403 One "strict" mode where the forward and reverse DNS lookups are done
 404 using the same LDAP objects, and a "tree" mode where the forward and
 405 reverse entries are in two different subtrees in LDAP with a structure
 406 based on the DNS names, as in tjener.intern and
 407 2.2.0.10.in-addr.arpa.</p>
 408
 409 <p>In tree mode, the server is set up to use a LDAP subtree as its
 410 base, and uses a "base" scoped search for the DNS name by adding
 411 "dc=tjener,dc=intern," to the base with a filter for
 412 "(associateddomain=tjener.intern)" for the forward entry and
 413 "dc=2,dc=2,dc=0,dc=10,dc=in-addr,dc=arpa," with a filter for
 414 "(associateddomain=2.2.0.10.in-addr.arpa)" for the reverse entry.  For
 415 forward entries, it is looking for attributes named dnsttl, arecord,
 416 nsrecord, cnamerecord, soarecord, ptrrecord, hinforecord, mxrecord,
 417 txtrecord, rprecord, afsdbrecord, keyrecord, aaaarecord, locrecord,
 418 srvrecord, naptrrecord, kxrecord, certrecord, dsrecord, sshfprecord,
 419 ipseckeyrecord, rrsigrecord, nsecrecord, dnskeyrecord, dhcidrecord,
 420 spfrecord and modifytimestamp.  For reverse entries it is looking for
 421 the attributes dnsttl, arecord, nsrecord, cnamerecord, soarecord,
 422 ptrrecord, hinforecord, mxrecord, txtrecord, rprecord, aaaarecord,
 423 locrecord, srvrecord, naptrrecord and modifytimestamp.  The equivalent
 424 ldapsearch commands could look like this:</p>
 425
 426 <blockquote><pre>
 427 ldapsearch -h ldap \
 428   -b dc=tjener,dc=intern,ou=hosts,dc=skole,dc=skolelinux,dc=no \
 429   -s base -x '(associateddomain=tjener.intern)' dNSTTL aRecord nSRecord \
 430   cNAMERecord sOARecord pTRRecord hInfoRecord mXRecord tXTRecord \
 431   rPRecord aFSDBRecord KeyRecord aAAARecord lOCRecord sRVRecord \
 432   nAPTRRecord kXRecord certRecord dSRecord sSHFPRecord iPSecKeyRecord \
 433   rRSIGRecord nSECRecord dNSKeyRecord dHCIDRecord sPFRecord modifyTimestamp
 434
 435 ldapsearch -h ldap \
 436   -b dc=2,dc=2,dc=0,dc=10,dc=in-addr,dc=arpa,ou=hosts,dc=skole,dc=skolelinux,dc=no \
 437   -s base -x '(associateddomain=2.2.0.10.in-addr.arpa)'
 438   dnsttl, arecord, nsrecord, cnamerecord soarecord ptrrecord \
 439   hinforecord mxrecord txtrecord rprecord aaaarecord locrecord \
 440   srvrecord naptrrecord modifytimestamp
 441 </pre></blockquote>
 442
 443 <p>In Debian Edu/Lenny, the PowerDNS tree mode is used with
 444 ou=hosts,dc=skole,dc=skolelinux,dc=no as the base, and these are two
 445 example LDAP objects used there.  In addition to these objects, the
 446 parent objects all th way up to ou=hosts,dc=skole,dc=skolelinux,dc=no
 447 also exist.</p>
 448
 449 <blockquote><pre>
 450 dn: dc=tjener,dc=intern,ou=hosts,dc=skole,dc=skolelinux,dc=no
 451 objectclass: top
 452 objectclass: dnsdomain
 453 objectclass: domainrelatedobject
 454 dc: tjener
 455 arecord: 10.0.2.2
 456 associateddomain: tjener.intern
 457
 458 dn: dc=2,dc=2,dc=0,dc=10,dc=in-addr,dc=arpa,ou=hosts,dc=skole,dc=skolelinux,dc=no
 459 objectclass: top
 460 objectclass: dnsdomain2
 461 objectclass: domainrelatedobject
 462 dc: 2
 463 ptrrecord: tjener.intern
 464 associateddomain: 2.2.0.10.in-addr.arpa
 465 </pre></blockquote>
 466
 467 <p>In strict mode, the server behaves differently.  When looking for
 468 forward DNS entries, it is doing a "subtree" scoped search with the
 469 same base as in the tree mode for a object with filter
 470 "(associateddomain=tjener.intern)" and requests the attributes dnsttl,
 471 arecord, nsrecord, cnamerecord, soarecord, ptrrecord, hinforecord,
 472 mxrecord, txtrecord, rprecord, aaaarecord, locrecord, srvrecord,
 473 naptrrecord and modifytimestamp.  For reverse entires it also do a
 474 subtree scoped search but this time the filter is "(arecord=10.0.2.2)"
 475 and the requested attributes are associateddomain, dnsttl and
 476 modifytimestamp.  In short, in strict mode the objects with ptrrecord
 477 go away, and the arecord attribute in the forward object is used
 478 instead.</p>
 479
 480 <p>The forward and reverse searches can be simulated using ldapsearch
 481 like this:</p>
 482
 483 <blockquote><pre>
 484 ldapsearch -h ldap -b ou=hosts,dc=skole,dc=skolelinux,dc=no -s sub -x \
 485   '(associateddomain=tjener.intern)' dNSTTL aRecord nSRecord \
 486   cNAMERecord sOARecord pTRRecord hInfoRecord mXRecord tXTRecord \
 487   rPRecord aFSDBRecord KeyRecord aAAARecord lOCRecord sRVRecord \
 488   nAPTRRecord kXRecord certRecord dSRecord sSHFPRecord iPSecKeyRecord \
 489   rRSIGRecord nSECRecord dNSKeyRecord dHCIDRecord sPFRecord modifyTimestamp
 490
 491 ldapsearch -h ldap -b ou=hosts,dc=skole,dc=skolelinux,dc=no -s sub -x \
 492   '(arecord=10.0.2.2)' associateddomain dnsttl modifytimestamp
 493 </pre></blockquote>
 494
 495 <p>In addition to the forward and reverse searches , there is also a
 496 search for SOA records, which behave similar to the forward and
 497 reverse lookups.</p>
 498
 499 <p>A thing to note with the PowerDNS behaviour is that it do not
 500 specify any objectclass names, and instead look for the attributes it
 501 need to generate a DNS reply.  This make it able to work with any
 502 objectclass that provide the needed attributes.</p>
 503
 504 <p>The attributes are normally provided in the cosine (RFC 1274) and
 505 dnsdomain2 schemas.  The latter is used for reverse entries like
 506 ptrrecord and recent DNS additions like aaaarecord and srvrecord.</p>
 507
 508 <p>In Debian Edu, we have created DNS objects using the object classes
 509 dcobject (for dc), dnsdomain or dnsdomain2 (structural, for the DNS
 510 attributes) and domainrelatedobject (for associatedDomain).  The use
 511 of structural object classes make it impossible to combine these
 512 classes with the object classes used by DHCP.</p>
 513
 514 <p>There are other schemas that could be used too, for example the
 515 dnszone structural object class used by Gosa and bind-sdb for the DNS
 516 attributes combined with the domainrelatedobject object class, but in
 517 this case some unused attributes would have to be included as well
 518 (zonename and relativedomainname).</p>
 519
 520 <p>My proposal for Debian Edu would be to switch PowerDNS to strict
 521 mode and not use any of the existing objectclasses (dnsdomain,
 522 dnsdomain2 and dnszone) when one want to combine the DNS information
 523 with DHCP information, and instead create a auxiliary object class
 524 defined something like this (using the attributes defined for
 525 dnsdomain and dnsdomain2 or dnszone):</p>
 526
 527 <blockquote><pre>
 528 objectclass ( some-oid NAME 'dnsDomainAux'
 529     SUP top
 530     AUXILIARY
 531     MAY ( ARecord $ MDRecord $ MXRecord $ NSRecord $ SOARecord $ CNAMERecord $
 532           DNSTTL $ DNSClass $ PTRRecord $ HINFORecord $ MINFORecord $
 533           TXTRecord $ SIGRecord $ KEYRecord $ AAAARecord $ LOCRecord $
 534           NXTRecord $ SRVRecord $ NAPTRRecord $ KXRecord $ CERTRecord $
 535           A6Record $ DNAMERecord
 536     ))
 537 </pre></blockquote>
 538
 539 <p>This will allow any object to become a DNS entry when combined with
 540 the domainrelatedobject object class, and allow any entity to include
 541 all the attributes PowerDNS wants.  I've sent an email to the PowerDNS
 542 developers asking for their view on this schema and if they are
 543 interested in providing such schema with PowerDNS, and I hope my
 544 message will be accepted into their mailing list soon.</p>
 545
 546 <p><strong>ISC dhcp</strong></p>
 547
 548 <p>The DHCP server searches for specific objectclass and requests all
 549 the object attributes, and then uses the attributes it want.  This
 550 make it harder to figure out exactly what attributes are used, but
 551 thanks to the working example in Debian Edu I can at least get an idea
 552 what is needed without having to read the source code.</p>
 553
 554 <p>In the DHCP server configuration, the LDAP base to use and the
 555 search filter to use to locate the correct dhcpServer entity is
 556 stored.  These are the relevant entries from
 557 /etc/dhcp3/dhcpd.conf:</p>
 558
 559 <blockquote><pre>
 560 ldap-base-dn "dc=skole,dc=skolelinux,dc=no";
 561 ldap-dhcp-server-cn "dhcp";
 562 </pre></blockquote>
 563
 564 <p>The DHCP server uses this information to nest all the DHCP
 565 configuration it need.  The cn "dhcp" is located using the given LDAP
 566 base and the filter "(&(objectClass=dhcpServer)(cn=dhcp))".  The
 567 search result is this entry:</p>
 568
 569 <blockquote><pre>
 570 dn: cn=dhcp,dc=skole,dc=skolelinux,dc=no
 571 cn: dhcp
 572 objectClass: top
 573 objectClass: dhcpServer
 574 dhcpServiceDN: cn=DHCP Config,dc=skole,dc=skolelinux,dc=no
 575 </pre></blockquote>
 576
 577 <p>The content of the dhcpServiceDN attribute is next used to locate the
 578 subtree with DHCP configuration.  The DHCP configuration subtree base
 579 is located using a base scope search with base "cn=DHCP
 580 Config,dc=skole,dc=skolelinux,dc=no" and filter
 581 "(&(objectClass=dhcpService)(|(dhcpPrimaryDN=cn=dhcp,dc=skole,dc=skolelinux,dc=no)(dhcpSecondaryDN=cn=dhcp,dc=skole,dc=skolelinux,dc=no)))".
 582 The search result is this entry:</p>
 583
 584 <blockquote><pre>
 585 dn: cn=DHCP Config,dc=skole,dc=skolelinux,dc=no
 586 cn: DHCP Config
 587 objectClass: top
 588 objectClass: dhcpService
 589 objectClass: dhcpOptions
 590 dhcpPrimaryDN: cn=dhcp, dc=skole,dc=skolelinux,dc=no
 591 dhcpStatements: ddns-update-style none
 592 dhcpStatements: authoritative
 593 dhcpOption: smtp-server code 69 = array of ip-address
 594 dhcpOption: www-server code 72 = array of ip-address
 595 dhcpOption: wpad-url code 252 = text
 596 </pre></blockquote>
 597
 598 <p>Next, the entire subtree is processed, one level at the time.  When
 599 all the DHCP configuration is loaded, it is ready to receive requests.
 600 The subtree in Debian Edu contain objects with object classes
 601 top/dhcpService/dhcpOptions, top/dhcpSharedNetwork/dhcpOptions,
 602 top/dhcpSubnet, top/dhcpGroup and top/dhcpHost.  These provide options
 603 and information about netmasks, dynamic range etc.  Leaving out the
 604 details here because it is not relevant for the focus of my
 605 investigation, which is to see if it is possible to merge dns and dhcp
 606 related computer objects.</p>
 607
 608 <p>When a DHCP request come in, LDAP is searched for the MAC address
 609 of the client (00:00:00:00:00:00 in this example), using a subtree
 610 scoped search with "cn=DHCP Config,dc=skole,dc=skolelinux,dc=no" as
 611 the base and "(&(objectClass=dhcpHost)(dhcpHWAddress=ethernet
 612 00:00:00:00:00:00))" as the filter.  This is what a host object look
 613 like:</p>
 614
 615 <blockquote><pre>
 616 dn: cn=hostname,cn=group1,cn=THINCLIENTS,cn=DHCP Config,dc=skole,dc=skolelinux,dc=no
 617 cn: hostname
 618 objectClass: top
 619 objectClass: dhcpHost
 620 dhcpHWAddress: ethernet 00:00:00:00:00:00
 621 dhcpStatements: fixed-address hostname
 622 </pre></blockquote>
 623
 624 <p>There is less flexiblity in the way LDAP searches are done here.
 625 The object classes need to have fixed names, and the configuration
 626 need to be stored in a fairly specific LDAP structure.  On the
 627 positive side, the invidiual dhcpHost entires can be anywhere without
 628 the DN pointed to by the dhcpServer entries.  The latter should make
 629 it possible to group all host entries in a subtree next to the
 630 configuration entries, and this subtree can also be shared with the
 631 DNS server if the schema proposed above is combined with the dhcpHost
 632 structural object class.
 633
 634 <p><strong>Conclusion</strong></p>
 635
 636 <p>The PowerDNS implementation seem to be very flexible when it come
 637 to which LDAP schemas to use.  While its "tree" mode is rigid when it
 638 come to the the LDAP structure, the "strict" mode is very flexible,
 639 allowing DNS objects to be stored anywhere under the base cn specified
 640 in the configuration.</p>
 641
 642 <p>The DHCP implementation on the other hand is very inflexible, both
 643 regarding which LDAP schemas to use and which LDAP structure to use.
 644 I guess one could implement ones own schema, as long as the
 645 objectclasses and attributes have the names used, but this do not
 646 really help when the DHCP subtree need to have a fairly fixed
 647 structure.</p>
 648
 649 <p>Based on the observed behaviour, I suspect a LDAP structure like
 650 this might work for Debian Edu:</p>
 651
 652 <blockquote><pre>
 653 ou=services
 654   cn=machine-info (dhcpService) - dhcpServiceDN points here
 655     cn=dhcp (dhcpServer)
 656     cn=dhcp-internal (dhcpSharedNetwork/dhcpOptions)
 657       cn=10.0.2.0 (dhcpSubnet)
 658         cn=group1 (dhcpGroup/dhcpOptions)
 659     cn=dhcp-thinclients (dhcpSharedNetwork/dhcpOptions)
 660       cn=192.168.0.0 (dhcpSubnet)
 661         cn=group1 (dhcpGroup/dhcpOptions)
 662     ou=machines - PowerDNS base points here
 663       cn=hostname (dhcpHost/domainrelatedobject/dnsDomainAux)
 664 </pre></blockquote>
 665
 666 <P>This is not tested yet.  If the DHCP server require the dhcpHost
 667 entries to be in the dhcpGroup subtrees, the entries can be stored
 668 there instead of a common machines subtree, and the PowerDNS base
 669 would have to be moved one level up to the machine-info subtree.</p>
 670
 671 <p>The combined object under the machines subtree would look something
 672 like this:</p>
 673
 674 <blockquote><pre>
 675 dn: dc=hostname,ou=machines,cn=machine-info,dc=skole,dc=skolelinux,dc=no
 676 dc: hostname
 677 objectClass: top
 678 objectClass: dhcpHost
 679 objectclass: domainrelatedobject
 680 objectclass: dnsDomainAux
 681 associateddomain: hostname.intern
 682 arecord: 10.11.12.13
 683 dhcpHWAddress: ethernet 00:00:00:00:00:00
 684 dhcpStatements: fixed-address hostname.intern
 685 </pre></blockquote>
 686
 687 </p>One could even add the LTSP configuration associated with a given
 688 machine, as long as the required attributes are available in a
 689 auxiliary object class.</p>
 690 </div>
 691   <div class="tags">
 692
 693
 694
 695    Tags: <a href="http://people.skolelinux.org/pere/blog/tags/debian">debian</a>, <a href="http://people.skolelinux.org/pere/blog/tags/debian edu">debian edu</a>, <a href="http://people.skolelinux.org/pere/blog/tags/english">english</a>, <a href="http://people.skolelinux.org/pere/blog/tags/ldap">ldap</a>, <a href="http://people.skolelinux.org/pere/blog/tags/nuug">nuug</a>.
 696
 697   </div>
 698  </div>
 699  <div class="padding"></div>
 700
 701  <div class="entry">
 702   <div class="title"><a href="http://people.skolelinux.org/pere/blog/Combining_PowerDNS_and_ISC_DHCP_LDAP_objects.html">Combining PowerDNS and ISC DHCP LDAP objects</a></div>
 703   <div class="date">2010-07-14 23:45</div>
 704   <div class="body">
 705 <p>For a while now, I have wanted to find a way to change the DNS and
 706 DHCP services in Debian Edu to use the same LDAP objects for a given
 707 computer, to avoid the possibility of having a inconsistent state for
 708 a computer in LDAP (as in DHCP but no DNS entry or the other way
 709 around) and make it easier to add computers to LDAP.</p>
 710
 711 <p>I've looked at how powerdns and dhcpd is using LDAP, and using this
 712 information finally found a solution that seem to work.</p>
 713
 714 <p>The old setup required three LDAP objects for a given computer.
 715 One forward DNS entry, one reverse DNS entry and one DHCP entry.  If
 716 we switch powerdns to use its strict LDAP method (ldap-method=strict
 717 in pdns-debian-edu.conf), the forward and reverse DNS entries are
 718 merged into one while making it impossible to transfer the reverse map
 719 to a slave DNS server.</p>
 720
 721 <p>If we also replace the object class used to get the DNS related
 722 attributes to one allowing these attributes to be combined with the
 723 dhcphost object class, we can merge the DNS and DHCP entries into one.
 724 I've written such object class in the dnsdomainaux.schema file (need
 725 proper OIDs, but that is a minor issue), and tested the setup.  It
 726 seem to work.</p>
 727
 728 <p>With this test setup in place, we can get away with one LDAP object
 729 for both DNS and DHCP, and even the LTSP configuration I suggested in
 730 an earlier email.  The combined LDAP object will look something like
 731 this:</p>
 732
 733 <blockquote><pre>
 734   dn: cn=hostname,cn=group1,cn=THINCLIENTS,cn=DHCP Config,dc=skole,dc=skolelinux,dc=no
 735   cn: hostname
 736   objectClass: dhcphost
 737   objectclass: domainrelatedobject
 738   objectclass: dnsdomainaux
 739   associateddomain: hostname.intern
 740   arecord: 10.11.12.13
 741   dhcphwaddress: ethernet 00:00:00:00:00:00
 742   dhcpstatements: fixed-address hostname
 743   ldapconfigsound: Y
 744 </pre></blockquote>
 745
 746 <p>The DNS server uses the associateddomain and arecord entries, while
 747 the DHCP server uses the dhcphwaddress and dhcpstatements entries
 748 before asking DNS to resolve the fixed-adddress.  LTSP will use
 749 dhcphwaddress or associateddomain and the ldapconfig* attributes.</p>
 750
 751 <p>I am not yet sure if I can get the DHCP server to look for its
 752 dhcphost in a different location, to allow us to put the objects
 753 outside the "DHCP Config" subtree, but hope to figure out a way to do
 754 that.  If I can't figure out a way to do that, we can still get rid of
 755 the hosts subtree and move all its content into the DHCP Config tree
 756 (which probably should be renamed to be more related to the new
 757 content.  I suspect cn=dnsdhcp,ou=services or something like that
 758 might be a good place to put it.</p>
 759
 760 <p>If you want to help out with implementing this for Debian Edu,
 761 please contact us on debian-edu@lists.debian.org.</p>
 762 </div>
 763   <div class="tags">
 764
 765
 766
 767    Tags: <a href="http://people.skolelinux.org/pere/blog/tags/debian">debian</a>, <a href="http://people.skolelinux.org/pere/blog/tags/debian edu">debian edu</a>, <a href="http://people.skolelinux.org/pere/blog/tags/english">english</a>, <a href="http://people.skolelinux.org/pere/blog/tags/ldap">ldap</a>, <a href="http://people.skolelinux.org/pere/blog/tags/nuug">nuug</a>.
 768
 769   </div>
 770  </div>
 771  <div class="padding"></div>
 772
 773  <div class="entry">
 774   <div class="title"><a href="http://people.skolelinux.org/pere/blog/Idea_for_storing_LTSP_configuration_in_LDAP.html">Idea for storing LTSP configuration in LDAP</a></div>
 775   <div class="date">2010-07-11 22:00</div>
 776   <div class="body">
 777 <p>Vagrant mentioned on IRC today that ltsp_config now support
 778 sourcing files from /usr/share/ltsp/ltsp_config.d/ on the thin
 779 clients, and that this can be used to fetch configuration from LDAP if
 780 Debian Edu choose to store configuration there.</p>
 781
 782 <p>Armed with this information, I got inspired and wrote a test module
 783 to get configuration from LDAP.  The idea is to look up the MAC
 784 address of the client in LDAP, and look for attributes on the form
 785 ltspconfigsetting=value, and use this to export SETTING=value to the
 786 LTSP clients.</p>
 787
 788 <p>The goal is to be able to store the LTSP configuration attributes
 789 in a "computer" LDAP object used by both DNS and DHCP, and thus
 790 allowing us to store all information about a computer in one place.</p>
 791
 792 <p>This is a untested draft implementation, and I welcome feedback on
 793 this approach.  A real LDAP schema for the ltspClientAux objectclass
 794 need to be written.  Comments, suggestions, etc?</p>
 795
 796 <blockquote><pre>
 797 # Store in /opt/ltsp/$arch/usr/share/ltsp/ltsp_config.d/ldap-config
 798 #
 799 # Fetch LTSP client settings from LDAP based on MAC address
 800 #
 801 # Uses ethernet address as stored in the dhcpHost objectclass using
 802 # the dhcpHWAddress attribute or ethernet address stored in the
 803 # ieee802Device objectclass with the macAddress attribute.
 804 #
 805 # This module is written to be schema agnostic, and only depend on the
 806 # existence of attribute names.
 807 #
 808 # The LTSP configuration variables are saved directly using a
 809 # ltspConfig prefix and uppercasing the rest of the attribute name.
 810 # To set the SERVER variable, set the ltspConfigServer attribute.
 811 #
 812 # Some LDAP schema should be created with all the relevant
 813 # configuration settings.  Something like this should work:
 814 #
 815 # objectclass ( 1.1.2.2 NAME 'ltspClientAux'
 816 #     SUP top
 817 #     AUXILIARY
 818 #     MAY ( ltspConfigServer $ ltsConfigSound $ ... )
 819
 820 LDAPSERVER=$(debian-edu-ldapserver)
 821 if [ "$LDAPSERVER" ] ; then
 822     LDAPBASE=$(debian-edu-ldapserver -b)
 823     for MAC in $(LANG=C ifconfig |grep -i hwaddr| awk '{print $5}'|sort -u) ; do
 824         filter="(|(dhcpHWAddress=ethernet $MAC)(macAddress=$MAC))"
 825         ldapsearch -h "$LDAPSERVER" -b "$LDAPBASE" -v -x "$filter" | \
 826             grep '^ltspConfig' | while read attr value ; do
 827             # Remove prefix and convert to upper case
 828             attr=$(echo $attr | sed 's/^ltspConfig//i' | tr a-z A-Z)
 829             # bass value on to clients
 830             eval "$attr=$value; export $attr"
 831         done
 832     done
 833 fi
 834 </pre></blockquote>
 835
 836 <p>I'm not sure this shell construction will work, because I suspect
 837 the while block might end up in a subshell causing the variables set
 838 there to not show up in ltsp-config, but if that is the case I am sure
 839 the code can be restructured to make sure the variables are passed on.
 840 I expect that can be solved with some testing. :)</p>
 841
 842 <p>If you want to help out with implementing this for Debian Edu,
 843 please contact us on debian-edu@lists.debian.org.</p>
 844
 845 <p>Update 2010-07-17: I am aware of another effort to store LTSP
 846 configuration in LDAP that was created around year 2000 by
 847 <a href="http://www.pcxperience.com/thinclient/documentation/ldap.html">PC
 848 Xperience, Inc., 2000</a>.  I found its
 849 <a href="http://people.redhat.com/alikins/ltsp/ldap/">files</a> on a
 850 personal home page over at redhat.com.</p>
 851 </div>
 852   <div class="tags">
 853
 854
 855
 856    Tags: <a href="http://people.skolelinux.org/pere/blog/tags/debian">debian</a>, <a href="http://people.skolelinux.org/pere/blog/tags/debian edu">debian edu</a>, <a href="http://people.skolelinux.org/pere/blog/tags/english">english</a>, <a href="http://people.skolelinux.org/pere/blog/tags/ldap">ldap</a>, <a href="http://people.skolelinux.org/pere/blog/tags/nuug">nuug</a>.
 857
 858   </div>
 859  </div>
 860  <div class="padding"></div>
 861
 862  <div class="entry">
 863   <div class="title"><a href="http://people.skolelinux.org/pere/blog/jXplorer__a_very_nice_LDAP_GUI.html">jXplorer, a very nice LDAP GUI</a></div>
 864   <div class="date">2010-07-09 12:55</div>
 865   <div class="body">
 866 <p>Since
 867 <a href="http://people.skolelinux.org/pere/blog/LUMA__a_very_nice_LDAP_GUI.html">my
 868 last post</a> about available LDAP tools in Debian, I was told about a
 869 LDAP GUI that is even better than luma.  The java application
 870 <a href="http://jxplorer.org/">jXplorer</a> is claimed to be capable of
 871 moving LDAP objects and subtrees using drag-and-drop, and can
 872 authenticate using Kerberos.  I have only tested the Kerberos
 873 authentication, but do not have a LDAP setup allowing me to rewrite
 874 LDAP with my test user yet.  It is
 875 <a href="http://packages.qa.debian.org/j/jxplorer.html">available in
 876 Debian</a> testing and unstable at the moment.  The only problem I
 877 have with it is how it handle errors.  If something go wrong, its
 878 non-intuitive behaviour require me to go through some query work list
 879 and remove the failing query.  Nothing big, but very annoying.</p>
 880 </div>
 881   <div class="tags">
 882
 883
 884
 885    Tags: <a href="http://people.skolelinux.org/pere/blog/tags/debian">debian</a>, <a href="http://people.skolelinux.org/pere/blog/tags/debian edu">debian edu</a>, <a href="http://people.skolelinux.org/pere/blog/tags/english">english</a>, <a href="http://people.skolelinux.org/pere/blog/tags/ldap">ldap</a>, <a href="http://people.skolelinux.org/pere/blog/tags/nuug">nuug</a>.
 886
 887   </div>
 888  </div>
 889  <div class="padding"></div>
 890
 891  <p style="text-align: right;"><a href="index.rss"><img src="http://people.skolelinux.org/pere/blog/xml.gif" alt="RSS feed" width="36" height="14"></a></p>
 892
 893 <div id="sidebar">
 894
 895
 896
 897
 898
 899 <h2>Archive</h2>
 900 <ul>
 901
 902 <li>2010
 903 <ul>
 904
 905 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/01/">January (2)</a></li>
 906
 907 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/02/">February (1)</a></li>
 908
 909 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/03/">March (3)</a></li>
 910
 911 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/04/">April (3)</a></li>
 912
 913 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/05/">May (9)</a></li>
 914
 915 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/06/">June (14)</a></li>
 916
 917 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/07/">July (12)</a></li>
 918
 919 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/08/">August (1)</a></li>
 920
 921 </ul></li>
 922
 923 <li>2009
 924 <ul>
 925
 926 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/01/">January (8)</a></li>
 927
 928 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/02/">February (8)</a></li>
 929
 930 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/03/">March (12)</a></li>
 931
 932 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/04/">April (10)</a></li>
 933
 934 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/05/">May (9)</a></li>
 935
 936 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/06/">June (3)</a></li>
 937
 938 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/07/">July (4)</a></li>
 939
 940 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/08/">August (3)</a></li>
 941
 942 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/09/">September (1)</a></li>
 943
 944 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/10/">October (2)</a></li>
 945
 946 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/11/">November (3)</a></li>
 947
 948 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/12/">December (3)</a></li>
 949
 950 </ul></li>
 951
 952 <li>2008
 953 <ul>
 954
 955 <li><a href="http://people.skolelinux.org/pere/blog/archive/2008/11/">November (5)</a></li>
 956
 957 <li><a href="http://people.skolelinux.org/pere/blog/archive/2008/12/">December (7)</a></li>
 958
 959 </ul></li>
 960
 961 </ul>
 962
 963
 964
 965 <h2>Tags</h2>
 966 <ul>
 967
 968  <li><a href="http://people.skolelinux.org/pere/blog/tags/3d-printer">3d-printer (11)</a></li>
 969
 970  <li><a href="http://people.skolelinux.org/pere/blog/tags/amiga">amiga (1)</a></li>
 971
 972  <li><a href="http://people.skolelinux.org/pere/blog/tags/aros">aros (1)</a></li>
 973
 974  <li><a href="http://people.skolelinux.org/pere/blog/tags/bootsystem">bootsystem (10)</a></li>
 975
 976  <li><a href="http://people.skolelinux.org/pere/blog/tags/debian">debian (35)</a></li>
 977
 978  <li><a href="http://people.skolelinux.org/pere/blog/tags/debian edu">debian edu (37)</a></li>
 979
 980  <li><a href="http://people.skolelinux.org/pere/blog/tags/english">english (52)</a></li>
 981
 982  <li><a href="http://people.skolelinux.org/pere/blog/tags/fiksgatami">fiksgatami (1)</a></li>
 983
 984  <li><a href="http://people.skolelinux.org/pere/blog/tags/fildeling">fildeling (8)</a></li>
 985
 986  <li><a href="http://people.skolelinux.org/pere/blog/tags/kart">kart (3)</a></li>
 987
 988  <li><a href="http://people.skolelinux.org/pere/blog/tags/ldap">ldap (8)</a></li>
 989
 990  <li><a href="http://people.skolelinux.org/pere/blog/tags/lenker">lenker (1)</a></li>
 991
 992  <li><a href="http://people.skolelinux.org/pere/blog/tags/ltsp">ltsp (1)</a></li>
 993
 994  <li><a href="http://people.skolelinux.org/pere/blog/tags/multimedia">multimedia (5)</a></li>
 995
 996  <li><a href="http://people.skolelinux.org/pere/blog/tags/norsk">norsk (71)</a></li>
 997
 998  <li><a href="http://people.skolelinux.org/pere/blog/tags/nuug">nuug (89)</a></li>
 999
1000  <li><a href="http://people.skolelinux.org/pere/blog/tags/opphavsrett">opphavsrett (14)</a></li>
1001
1002  <li><a href="http://people.skolelinux.org/pere/blog/tags/personvern">personvern (14)</a></li>
1003
1004  <li><a href="http://people.skolelinux.org/pere/blog/tags/reprap">reprap (10)</a></li>
1005
1006  <li><a href="http://people.skolelinux.org/pere/blog/tags/rss">rss (1)</a></li>
1007
1008  <li><a href="http://people.skolelinux.org/pere/blog/tags/sikkerhet">sikkerhet (10)</a></li>
1009
1010  <li><a href="http://people.skolelinux.org/pere/blog/tags/sitesummary">sitesummary (3)</a></li>
1011
1012  <li><a href="http://people.skolelinux.org/pere/blog/tags/standard">standard (13)</a></li>
1013
1014  <li><a href="http://people.skolelinux.org/pere/blog/tags/stavekontroll">stavekontroll (1)</a></li>
1015
1016  <li><a href="http://people.skolelinux.org/pere/blog/tags/video">video (10)</a></li>
1017
1018  <li><a href="http://people.skolelinux.org/pere/blog/tags/vitenskap">vitenskap (1)</a></li>
1019
1020  <li><a href="http://people.skolelinux.org/pere/blog/tags/web">web (7)</a></li>
1021
1022 </ul>
1023
1024 </div>
1025
1026 <p style="text-align: right">
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