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  12   <h1>
  13        <a href="http://people.skolelinux.org/pere/blog/">Petter Reinholdtsen</a>
  14
  15   </h1>
  16
  17  </div>
  18
  19  <p>Entries tagged "ldap".</p>
  20
  21
  22
  23
  24 <div class="entry">
  25  <div class="title">
  26  <a href="http://people.skolelinux.org/pere/blog/Time_for_new__LDAP_schemas_replacing_RFC_2307_.html">Time for new  LDAP schemas replacing RFC 2307?</a>
  27  </div>
  28  <div class="date">
  29   2009-03-29 20:30
  30  </div>
  31
  32  <div class="body">
  33
  34 <p>The state of standardized LDAP schemas on Linux is far from
  35 optimal.  There is RFC 2307 documenting one way to store NIS maps in
  36 LDAP, and a modified version of this normally called RFC 2307bis, with
  37 some modifications to be compatible with Active Directory.  The RFC
  38 specification handle the content of a lot of system databases, but do
  39 not handle DNS zones and DHCP configuration.</p>
  40
  41 <p>In <a href="http://www.skolelinux.org/">Debian Edu/Skolelinux</a>,
  42 we would like to store information about users, SMB clients/hosts,
  43 filegroups, netgroups (users and hosts), DHCP and DNS configuration,
  44 and LTSP configuration in LDAP.  These objects have a lot in common,
  45 but with the current LDAP schemas it is not possible to have one
  46 object per entity.  For example, one need to have at least three LDAP
  47 objects for a given computer, one with the SMB related stuff, one with
  48 DNS information and another with DHCP information.  The schemas
  49 provided for DNS and DHCP are impossible to combine into one LDAP
  50 object.  In addition, it is impossible to implement quick queries for
  51 netgroup membership, because of the way NIS triples are implemented.
  52 It just do not scale.  I believe it is time for a few RFC
  53 specifications to cleam up this mess.</p>
  54
  55 <p>I would like to have one LDAP object representing each computer in
  56 the network, and this object can then keep the SMB (ie host key), DHCP
  57 (mac address/name) and DNS (name/IP address) settings in one place.
  58 It need to be efficently stored to make sure it scale well.</p>
  59
  60 <p>I would also like to have a quick way to map from a user or
  61 computer and to the net group this user or computer is a member.</p>
  62
  63 <p>Active Directory have done a better job than unix heads like myself
  64 in this regard, and the unix side need to catch up.  Time to start a
  65 new IETF work group?</p>
  66
  67  </div>
  68  <div class="tags">
  69
  70
  71
  72   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>.
  73
  74  </div>
  75 </div>
  76 <div class="padding"></div>
  77
  78 <div class="entry">
  79  <div class="title">
  80  <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">Idea for a change to LDAP schemas allowing DNS and DHCP info to be combined into one object</a>
  81  </div>
  82  <div class="date">
  83   2010-06-24 00:35
  84  </div>
  85
  86  <div class="body">
  87
  88 <p>A while back, I
  89 <a href="http://people.skolelinux.org/pere/blog/Time_for_new__LDAP_schemas_replacing_RFC_2307_.html">complained
  90 about the fact</a> that it is not possible with the provided schemas
  91 for storing DNS and DHCP information in LDAP to combine the two sets
  92 of information into one LDAP object representing a computer.</p>
  93
  94 <p>In the mean time, I discovered that a simple fix would be to make
  95 the dhcpHost object class auxiliary, to allow it to be combined with
  96 the dNSDomain object class, and thus forming one object for one
  97 computer when storing both DHCP and DNS information in LDAP.</p>
  98
  99 <p>If I understand this correctly, it is not safe to do this change
 100 without also changing the assigned number for the object class, and I
 101 do not know enough about LDAP schema design to do that properly for
 102 Debian Edu.</p>
 103
 104 <p>Anyway, for future reference, this is how I believe we could change
 105 the
 106 <a href="http://tools.ietf.org/html/draft-ietf-dhc-ldap-schema-00">DHCP
 107 schema</a> to solve at least part of the problem with the LDAP schemas
 108 available today from IETF.</p>
 109
 110 <pre>
 111 --- dhcp.schema    (revision 65192)
 112 +++ dhcp.schema    (working copy)
 113 @@ -376,7 +376,7 @@
 114  objectclass ( 2.16.840.1.113719.1.203.6.6
 115         NAME 'dhcpHost'
 116         DESC 'This represents information about a particular client'
 117 -       SUP top
 118 +       SUP top AUXILIARY
 119         MUST cn
 120         MAY  (dhcpLeaseDN $ dhcpHWAddress $ dhcpOptionsDN $ dhcpStatements $ dhcpComments $ dhcpOption)
 121         X-NDS_CONTAINMENT ('dhcpService' 'dhcpSubnet' 'dhcpGroup') )
 122 </pre>
 123
 124 <p>I very much welcome clues on how to do this properly for Debian
 125 Edu/Squeeze.  We provide the DHCP schema in our debian-edu-config
 126 package, and should thus be free to rewrite it as we see fit.</p>
 127
 128 <p>If you want to help out with implementing this for Debian Edu,
 129 please contact us on debian-edu@lists.debian.org.</p>
 130
 131  </div>
 132  <div class="tags">
 133
 134
 135
 136   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>.
 137
 138  </div>
 139 </div>
 140 <div class="padding"></div>
 141
 142 <div class="entry">
 143  <div class="title">
 144  <a href="http://people.skolelinux.org/pere/blog/LUMA__a_very_nice_LDAP_GUI.html">LUMA, a very nice LDAP GUI</a>
 145  </div>
 146  <div class="date">
 147   2010-06-28 00:30
 148  </div>
 149
 150  <div class="body">
 151
 152 <p>The last few days I have been looking into the status of the LDAP
 153 directory in Debian Edu, and in the process I started to miss a GUI
 154 tool to browse the LDAP tree.  The only one I was able to find in
 155 Debian/Squeeze and Lenny is
 156 <a href="http://luma.sourceforge.net/">LUMA</a>, which has proved to
 157 be a great tool to get a overview of the current LDAP directory
 158 populated by default in Skolelinux.  Thanks to it, I have been able to
 159 find empty and obsolete subtrees, misplaced objects and duplicate
 160 objects.  It will be installed by default in Debian/Squeeze.  If you
 161 are working with LDAP, give it a go. :)</p>
 162
 163 <p>I did notice one problem with it I have not had time to report to
 164 the BTS yet.  There is no .desktop file in the package, so the tool do
 165 not show up in the Gnome and KDE menus, but only deep down in in the
 166 Debian submenu in KDE.  I hope that can be fixed before Squeeze is
 167 released.</p>
 168
 169 <p>I have not yet been able to get it to modify the tree yet.  I would
 170 like to move objects and remove subtrees directly in the GUI, but have
 171 not found a way to do that with LUMA yet.  So in the mean time, I use
 172 <a href="http://www.lichteblau.com/ldapvi/">ldapvi</a> for that.</p>
 173
 174 <p>If you have tips on other GUI tools for LDAP that might be useful
 175 in Debian Edu, please contact us on debian-edu@lists.debian.org.</p>
 176
 177 <p>Update 2010-06-29: Ross Reedstrom tipped us about the
 178 <a href="http://packages.qa.debian.org/g/gq.html">gq</a> package as a
 179 useful GUI alternative.  It seem like a good tool, but is unmaintained
 180 in Debian and got a RC bug keeping it out of Squeeze.  Unless that
 181 changes, it will not be an option for Debian Edu based on Squeeze.</p>
 182
 183  </div>
 184  <div class="tags">
 185
 186
 187
 188   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>.
 189
 190  </div>
 191 </div>
 192 <div class="padding"></div>
 193
 194 <div class="entry">
 195  <div class="title">
 196  <a href="http://people.skolelinux.org/pere/blog/Caching_password__user_and_group_on_a_roaming_Debian_laptop.html">Caching password, user and group on a roaming Debian laptop</a>
 197  </div>
 198  <div class="date">
 199   2010-07-01 11:40
 200  </div>
 201
 202  <div class="body">
 203
 204 <p>For a laptop, centralized user directories and password checking is
 205 a bit troubling.  Laptops are typically used also when not connected
 206 to the network, and it is vital for a user to be able to log in or
 207 unlock the screen saver also when a central server is unavailable.
 208 This is possible by caching passwords and directory information (user
 209 and group attributes) locally, and the packages to do so are available
 210 in Debian.  Here follow two recipes to set this up in Debian/Squeeze.
 211 It is also possible to set up in Debian/Lenny, but require more manual
 212 setup there because pam-auth-update is missing in Lenny.</p>
 213
 214 <h2>LDAP/Kerberos + nscd + libpam-ccreds + libpam-mklocaluser/pam_mkhomedir</h2>
 215
 216 This is the traditional method with a twist.  The password caching is
 217 provided by libpam-ccreds (version 10-4 or later is needed on
 218 Squeeze), and the directory caching is done by nscd.  The directory
 219 lookup and password checking is done using LDAP.  If one want to use
 220 Kerberos for password checking the libpam-ldapd package can be
 221 replaced with libpam-krb5 or libpam-heimdal.  If one is happy having a
 222 local home directory with the path listed in LDAP, one can use the
 223 pam_mkhomedir module from pam-modules to make this happen instead of
 224 using libpam-mklocaluser.  A setup for pam-auth-update to enable
 225 pam_mkhomedir will have to be written until a fix for
 226 <a href="http://bugs.debian.org/568577">bug #568577</a> is in the
 227 archive.  Because I believe it is a bad idea to have local home
 228 directories using misleading paths like /site/server/partition/, I
 229 prefer to create a local user with the home directory in /home/.  This
 230 is done using the libpam-mklocaluser package.</p>
 231
 232 <p>These packages need to be installed and configured</p>
 233
 234 <blockquote><pre>
 235 libnss-ldapd libpam-ldapd nscd libpam-ccreds libpam-mklocaluser
 236 </pre></blockquote>
 237
 238 <p>The ldapd packages will ask for LDAP connection information, and
 239 one have to fill in the values that fits ones own site.  Make sure the
 240 PAM part uses encrypted connections, to make sure the password is not
 241 sent in clear text to the LDAP server.  I've been unable to get TLS
 242 certificate checking for a self signed certificate working, which make
 243 LDAP authentication unsafe for Debian Edu (nslcd is not checking if it
 244 is talking to the correct LDAP server), and very much welcome feedback
 245 on how to get this working.</p>
 246
 247 <p>Because nscd do not have a default configuration fit for offline
 248 caching until <a href="http://bugs.debian.org/485282">bug #485282</a>
 249 is fixed, this configuration should be used instead of the one
 250 currently in /etc/nscd.conf.  The changes are in the fields
 251 reload-count and positive-time-to-live, and is based on the
 252 instructions I found in the
 253 <a href="http://www.flyn.org/laptopldap/">LDAP for Mobile Laptops</a>
 254 instructions by Flyn Computing.</p>
 255
 256 <blockquote><pre>
 257         debug-level             0
 258         reload-count            unlimited
 259         paranoia                no
 260
 261         enable-cache            passwd          yes
 262         positive-time-to-live   passwd          2592000
 263         negative-time-to-live   passwd          20
 264         suggested-size          passwd          211
 265         check-files             passwd          yes
 266         persistent              passwd          yes
 267         shared                  passwd          yes
 268         max-db-size             passwd          33554432
 269         auto-propagate          passwd          yes
 270
 271         enable-cache            group           yes
 272         positive-time-to-live   group           2592000
 273         negative-time-to-live   group           20
 274         suggested-size          group           211
 275         check-files             group           yes
 276         persistent              group           yes
 277         shared                  group           yes
 278         max-db-size             group           33554432
 279         auto-propagate          group           yes
 280
 281         enable-cache            hosts           no
 282         positive-time-to-live   hosts           2592000
 283         negative-time-to-live   hosts           20
 284         suggested-size          hosts           211
 285         check-files             hosts           yes
 286         persistent              hosts           yes
 287         shared                  hosts           yes
 288         max-db-size             hosts           33554432
 289
 290         enable-cache            services        yes
 291         positive-time-to-live   services        2592000
 292         negative-time-to-live   services        20
 293         suggested-size          services        211
 294         check-files             services        yes
 295         persistent              services        yes
 296         shared                  services        yes
 297         max-db-size             services        33554432
 298 </pre></blockquote>
 299
 300 <p>While we wait for a mechanism to update /etc/nsswitch.conf
 301 automatically like the one provided in
 302 <a href="http://bugs.debian.org/496915">bug #496915</a>, the file
 303 content need to be manually replaced to ensure LDAP is used as the
 304 directory service on the machine.  /etc/nsswitch.conf should normally
 305 look like this:</p>
 306
 307 <blockquote><pre>
 308 passwd:         files ldap
 309 group:          files ldap
 310 shadow:         files ldap
 311 hosts:          files mdns4_minimal [NOTFOUND=return] dns mdns4
 312 networks:       files
 313 protocols:      files
 314 services:       files
 315 ethers:         files
 316 rpc:            files
 317 netgroup:       files ldap
 318 </pre></blockquote>
 319
 320 <p>The important parts are that ldap is listed last for passwd, group,
 321 shadow and netgroup.</p>
 322
 323 <p>With these changes in place, any user in LDAP will be able to log
 324 in locally on the machine using for example kdm, get a local home
 325 directory created and have the password as well as user and group
 326 attributes cached.
 327
 328 <h2>LDAP/Kerberos + nss-updatedb + libpam-ccreds +
 329   libpam-mklocaluser/pam_mkhomedir</h2>
 330
 331 <p>Because nscd have had its share of problems, and seem to have
 332 problems doing proper caching, I've seen suggestions and recipes to
 333 use nss-updatedb to copy parts of the LDAP database locally when the
 334 LDAP database is available.  I have not tested such setup, because I
 335 discovered sssd.</p>
 336
 337 <h2>LDAP/Kerberos + sssd + libpam-mklocaluser</h2>
 338
 339 <p>A more flexible and robust setup than the nscd combination
 340 mentioned earlier that has shown up recently, is the
 341 <a href="https://fedorahosted.org/sssd/">sssd</a> package from Redhat.
 342 It is part of the <a href="http://www.freeipa.org/">FreeIPA</A> project
 343 to provide a Active Directory like directory service for Linux
 344 machines.  The sssd system combines the caching of passwords and user
 345 information into one package, and remove the need for nscd and
 346 libpam-ccreds.  It support LDAP and Kerberos, but not NIS.  Version
 347 1.2 do not support netgroups, but it is said that it will support this
 348 in version 1.5 expected to show up later in 2010.  Because the
 349 <a href="http://packages.qa.debian.org/s/sssd.html">sssd package</a>
 350 was missing in Debian, I ended up co-maintaining it with Werner, and
 351 version 1.2 is now in testing.
 352
 353 <p>These packages need to be installed and configured to get the
 354 roaming setup I want</p>
 355
 356 <blockquote><pre>
 357 libpam-sss libnss-sss libpam-mklocaluser
 358 </pre></blockquote>
 359
 360 The complete setup of sssd is done by editing/creating
 361 <tt>/etc/sssd/sssd.conf</tt>.
 362
 363 <blockquote><pre>
 364 [sssd]
 365 config_file_version = 2
 366 reconnection_retries = 3
 367 sbus_timeout = 30
 368 services = nss, pam
 369 domains = INTERN
 370
 371 [nss]
 372 filter_groups = root
 373 filter_users = root
 374 reconnection_retries = 3
 375
 376 [pam]
 377 reconnection_retries = 3
 378
 379 [domain/INTERN]
 380 enumerate = false
 381 cache_credentials = true
 382
 383 id_provider = ldap
 384 auth_provider = ldap
 385 chpass_provider = ldap
 386
 387 ldap_uri = ldap://ldap
 388 ldap_search_base = dc=skole,dc=skolelinux,dc=no
 389 ldap_tls_reqcert = never
 390 ldap_tls_cacert = /etc/ssl/certs/ca-certificates.crt
 391 </pre></blockquote>
 392
 393 <p>I got the same problem here with certificate checking.  Had to set
 394 "ldap_tls_reqcert = never" to get it working.</p>
 395
 396 <p>With the libnss-sss package in testing at the moment, the
 397 nsswitch.conf file is update automatically, so there is no need to
 398 modify it manually.</p>
 399
 400 <p>If you want to help out with implementing this for Debian Edu,
 401 please contact us on debian-edu@lists.debian.org.</p>
 402
 403  </div>
 404  <div class="tags">
 405
 406
 407
 408   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/ldap">ldap</a>, <a href="http://people.skolelinux.org/pere/blog/tags/nuug">nuug</a>.
 409
 410  </div>
 411 </div>
 412 <div class="padding"></div>
 413
 414 <div class="entry">
 415  <div class="title">
 416  <a href="http://people.skolelinux.org/pere/blog/jXplorer__a_very_nice_LDAP_GUI.html">jXplorer, a very nice LDAP GUI</a>
 417  </div>
 418  <div class="date">
 419   2010-07-09 12:55
 420  </div>
 421
 422  <div class="body">
 423
 424 <p>Since
 425 <a href="http://people.skolelinux.org/pere/blog/LUMA__a_very_nice_LDAP_GUI.html">my
 426 last post</a> about available LDAP tools in Debian, I was told about a
 427 LDAP GUI that is even better than luma.  The java application
 428 <a href="http://jxplorer.org/">jXplorer</a> is claimed to be capable of
 429 moving LDAP objects and subtrees using drag-and-drop, and can
 430 authenticate using Kerberos.  I have only tested the Kerberos
 431 authentication, but do not have a LDAP setup allowing me to rewrite
 432 LDAP with my test user yet.  It is
 433 <a href="http://packages.qa.debian.org/j/jxplorer.html">available in
 434 Debian</a> testing and unstable at the moment.  The only problem I
 435 have with it is how it handle errors.  If something go wrong, its
 436 non-intuitive behaviour require me to go through some query work list
 437 and remove the failing query.  Nothing big, but very annoying.</p>
 438
 439  </div>
 440  <div class="tags">
 441
 442
 443
 444   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>.
 445
 446  </div>
 447 </div>
 448 <div class="padding"></div>
 449
 450 <div class="entry">
 451  <div class="title">
 452  <a href="http://people.skolelinux.org/pere/blog/Idea_for_storing_LTSP_configuration_in_LDAP.html">Idea for storing LTSP configuration in LDAP</a>
 453  </div>
 454  <div class="date">
 455   2010-07-11 22:00
 456  </div>
 457
 458  <div class="body">
 459
 460 <p>Vagrant mentioned on IRC today that ltsp_config now support
 461 sourcing files from /usr/share/ltsp/ltsp_config.d/ on the thin
 462 clients, and that this can be used to fetch configuration from LDAP if
 463 Debian Edu choose to store configuration there.</p>
 464
 465 <p>Armed with this information, I got inspired and wrote a test module
 466 to get configuration from LDAP.  The idea is to look up the MAC
 467 address of the client in LDAP, and look for attributes on the form
 468 ltspconfigsetting=value, and use this to export SETTING=value to the
 469 LTSP clients.</p>
 470
 471 <p>The goal is to be able to store the LTSP configuration attributes
 472 in a "computer" LDAP object used by both DNS and DHCP, and thus
 473 allowing us to store all information about a computer in one place.</p>
 474
 475 <p>This is a untested draft implementation, and I welcome feedback on
 476 this approach.  A real LDAP schema for the ltspClientAux objectclass
 477 need to be written.  Comments, suggestions, etc?</p>
 478
 479 <blockquote><pre>
 480 # Store in /opt/ltsp/$arch/usr/share/ltsp/ltsp_config.d/ldap-config
 481 #
 482 # Fetch LTSP client settings from LDAP based on MAC address
 483 #
 484 # Uses ethernet address as stored in the dhcpHost objectclass using
 485 # the dhcpHWAddress attribute or ethernet address stored in the
 486 # ieee802Device objectclass with the macAddress attribute.
 487 #
 488 # This module is written to be schema agnostic, and only depend on the
 489 # existence of attribute names.
 490 #
 491 # The LTSP configuration variables are saved directly using a
 492 # ltspConfig prefix and uppercasing the rest of the attribute name.
 493 # To set the SERVER variable, set the ltspConfigServer attribute.
 494 #
 495 # Some LDAP schema should be created with all the relevant
 496 # configuration settings.  Something like this should work:
 497 #
 498 # objectclass ( 1.1.2.2 NAME 'ltspClientAux'
 499 #     SUP top
 500 #     AUXILIARY
 501 #     MAY ( ltspConfigServer $ ltsConfigSound $ ... )
 502
 503 LDAPSERVER=$(debian-edu-ldapserver)
 504 if [ "$LDAPSERVER" ] ; then
 505     LDAPBASE=$(debian-edu-ldapserver -b)
 506     for MAC in $(LANG=C ifconfig |grep -i hwaddr| awk '{print $5}'|sort -u) ; do
 507         filter="(|(dhcpHWAddress=ethernet $MAC)(macAddress=$MAC))"
 508         ldapsearch -h "$LDAPSERVER" -b "$LDAPBASE" -v -x "$filter" | \
 509             grep '^ltspConfig' | while read attr value ; do
 510             # Remove prefix and convert to upper case
 511             attr=$(echo $attr | sed 's/^ltspConfig//i' | tr a-z A-Z)
 512             # bass value on to clients
 513             eval "$attr=$value; export $attr"
 514         done
 515     done
 516 fi
 517 </pre></blockquote>
 518
 519 <p>I'm not sure this shell construction will work, because I suspect
 520 the while block might end up in a subshell causing the variables set
 521 there to not show up in ltsp-config, but if that is the case I am sure
 522 the code can be restructured to make sure the variables are passed on.
 523 I expect that can be solved with some testing. :)</p>
 524
 525 <p>If you want to help out with implementing this for Debian Edu,
 526 please contact us on debian-edu@lists.debian.org.</p>
 527
 528 <p>Update 2010-07-17: I am aware of another effort to store LTSP
 529 configuration in LDAP that was created around year 2000 by
 530 <a href="http://www.pcxperience.com/thinclient/documentation/ldap.html">PC
 531 Xperience, Inc., 2000</a>.  I found its
 532 <a href="http://people.redhat.com/alikins/ltsp/ldap/">files</a> on a
 533 personal home page over at redhat.com.</p>
 534
 535  </div>
 536  <div class="tags">
 537
 538
 539
 540   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>.
 541
 542  </div>
 543 </div>
 544 <div class="padding"></div>
 545
 546 <div class="entry">
 547  <div class="title">
 548  <a href="http://people.skolelinux.org/pere/blog/Combining_PowerDNS_and_ISC_DHCP_LDAP_objects.html">Combining PowerDNS and ISC DHCP LDAP objects</a>
 549  </div>
 550  <div class="date">
 551   2010-07-14 23:45
 552  </div>
 553
 554  <div class="body">
 555
 556 <p>For a while now, I have wanted to find a way to change the DNS and
 557 DHCP services in Debian Edu to use the same LDAP objects for a given
 558 computer, to avoid the possibility of having a inconsistent state for
 559 a computer in LDAP (as in DHCP but no DNS entry or the other way
 560 around) and make it easier to add computers to LDAP.</p>
 561
 562 <p>I've looked at how powerdns and dhcpd is using LDAP, and using this
 563 information finally found a solution that seem to work.</p>
 564
 565 <p>The old setup required three LDAP objects for a given computer.
 566 One forward DNS entry, one reverse DNS entry and one DHCP entry.  If
 567 we switch powerdns to use its strict LDAP method (ldap-method=strict
 568 in pdns-debian-edu.conf), the forward and reverse DNS entries are
 569 merged into one while making it impossible to transfer the reverse map
 570 to a slave DNS server.</p>
 571
 572 <p>If we also replace the object class used to get the DNS related
 573 attributes to one allowing these attributes to be combined with the
 574 dhcphost object class, we can merge the DNS and DHCP entries into one.
 575 I've written such object class in the dnsdomainaux.schema file (need
 576 proper OIDs, but that is a minor issue), and tested the setup.  It
 577 seem to work.</p>
 578
 579 <p>With this test setup in place, we can get away with one LDAP object
 580 for both DNS and DHCP, and even the LTSP configuration I suggested in
 581 an earlier email.  The combined LDAP object will look something like
 582 this:</p>
 583
 584 <blockquote><pre>
 585   dn: cn=hostname,cn=group1,cn=THINCLIENTS,cn=DHCP Config,dc=skole,dc=skolelinux,dc=no
 586   cn: hostname
 587   objectClass: dhcphost
 588   objectclass: domainrelatedobject
 589   objectclass: dnsdomainaux
 590   associateddomain: hostname.intern
 591   arecord: 10.11.12.13
 592   dhcphwaddress: ethernet 00:00:00:00:00:00
 593   dhcpstatements: fixed-address hostname
 594   ldapconfigsound: Y
 595 </pre></blockquote>
 596
 597 <p>The DNS server uses the associateddomain and arecord entries, while
 598 the DHCP server uses the dhcphwaddress and dhcpstatements entries
 599 before asking DNS to resolve the fixed-adddress.  LTSP will use
 600 dhcphwaddress or associateddomain and the ldapconfig* attributes.</p>
 601
 602 <p>I am not yet sure if I can get the DHCP server to look for its
 603 dhcphost in a different location, to allow us to put the objects
 604 outside the "DHCP Config" subtree, but hope to figure out a way to do
 605 that.  If I can't figure out a way to do that, we can still get rid of
 606 the hosts subtree and move all its content into the DHCP Config tree
 607 (which probably should be renamed to be more related to the new
 608 content.  I suspect cn=dnsdhcp,ou=services or something like that
 609 might be a good place to put it.</p>
 610
 611 <p>If you want to help out with implementing this for Debian Edu,
 612 please contact us on debian-edu@lists.debian.org.</p>
 613
 614  </div>
 615  <div class="tags">
 616
 617
 618
 619   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>.
 620
 621  </div>
 622 </div>
 623 <div class="padding"></div>
 624
 625 <div class="entry">
 626  <div class="title">
 627  <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>
 628  </div>
 629  <div class="date">
 630   2010-07-17 21:00
 631  </div>
 632
 633  <div class="body">
 634
 635 <p>This is a
 636 <a href="http://people.skolelinux.org/pere/blog/Time_for_new__LDAP_schemas_replacing_RFC_2307_.html">followup</a>
 637 on my
 638 <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
 639 work</a> on
 640 <a href="http://people.skolelinux.org/pere/blog/Combining_PowerDNS_and_ISC_DHCP_LDAP_objects.html">merging
 641 all</a> the computer related LDAP objects in Debian Edu.</p>
 642
 643 <p>As a step to try to see if it possible to merge the DNS and DHCP
 644 LDAP objects, I have had a look at how the packages pdns-backend-ldap
 645 and dhcp3-server-ldap in Debian use the LDAP server.  The two
 646 implementations are quite different in how they use LDAP.</p>
 647
 648 To get this information, I started slapd with debugging enabled and
 649 dumped the debug output to a file to get the LDAP searches performed
 650 on a Debian Edu main-server.  Here is a summary.
 651
 652 <p><strong>powerdns</strong></p>
 653
 654 <a href="http://www.linuxnetworks.de/doc/index.php/PowerDNS_LDAP_Backend">Clues
 655 on how to</a> set up PowerDNS to use a LDAP backend is available on
 656 the web.
 657
 658 <p>PowerDNS have two modes of operation using LDAP as its backend.
 659 One "strict" mode where the forward and reverse DNS lookups are done
 660 using the same LDAP objects, and a "tree" mode where the forward and
 661 reverse entries are in two different subtrees in LDAP with a structure
 662 based on the DNS names, as in tjener.intern and
 663 2.2.0.10.in-addr.arpa.</p>
 664
 665 <p>In tree mode, the server is set up to use a LDAP subtree as its
 666 base, and uses a "base" scoped search for the DNS name by adding
 667 "dc=tjener,dc=intern," to the base with a filter for
 668 "(associateddomain=tjener.intern)" for the forward entry and
 669 "dc=2,dc=2,dc=0,dc=10,dc=in-addr,dc=arpa," with a filter for
 670 "(associateddomain=2.2.0.10.in-addr.arpa)" for the reverse entry.  For
 671 forward entries, it is looking for attributes named dnsttl, arecord,
 672 nsrecord, cnamerecord, soarecord, ptrrecord, hinforecord, mxrecord,
 673 txtrecord, rprecord, afsdbrecord, keyrecord, aaaarecord, locrecord,
 674 srvrecord, naptrrecord, kxrecord, certrecord, dsrecord, sshfprecord,
 675 ipseckeyrecord, rrsigrecord, nsecrecord, dnskeyrecord, dhcidrecord,
 676 spfrecord and modifytimestamp.  For reverse entries it is looking for
 677 the attributes dnsttl, arecord, nsrecord, cnamerecord, soarecord,
 678 ptrrecord, hinforecord, mxrecord, txtrecord, rprecord, aaaarecord,
 679 locrecord, srvrecord, naptrrecord and modifytimestamp.  The equivalent
 680 ldapsearch commands could look like this:</p>
 681
 682 <blockquote><pre>
 683 ldapsearch -h ldap \
 684   -b dc=tjener,dc=intern,ou=hosts,dc=skole,dc=skolelinux,dc=no \
 685   -s base -x '(associateddomain=tjener.intern)' dNSTTL aRecord nSRecord \
 686   cNAMERecord sOARecord pTRRecord hInfoRecord mXRecord tXTRecord \
 687   rPRecord aFSDBRecord KeyRecord aAAARecord lOCRecord sRVRecord \
 688   nAPTRRecord kXRecord certRecord dSRecord sSHFPRecord iPSecKeyRecord \
 689   rRSIGRecord nSECRecord dNSKeyRecord dHCIDRecord sPFRecord modifyTimestamp
 690
 691 ldapsearch -h ldap \
 692   -b dc=2,dc=2,dc=0,dc=10,dc=in-addr,dc=arpa,ou=hosts,dc=skole,dc=skolelinux,dc=no \
 693   -s base -x '(associateddomain=2.2.0.10.in-addr.arpa)'
 694   dnsttl, arecord, nsrecord, cnamerecord soarecord ptrrecord \
 695   hinforecord mxrecord txtrecord rprecord aaaarecord locrecord \
 696   srvrecord naptrrecord modifytimestamp
 697 </pre></blockquote>
 698
 699 <p>In Debian Edu/Lenny, the PowerDNS tree mode is used with
 700 ou=hosts,dc=skole,dc=skolelinux,dc=no as the base, and these are two
 701 example LDAP objects used there.  In addition to these objects, the
 702 parent objects all th way up to ou=hosts,dc=skole,dc=skolelinux,dc=no
 703 also exist.</p>
 704
 705 <blockquote><pre>
 706 dn: dc=tjener,dc=intern,ou=hosts,dc=skole,dc=skolelinux,dc=no
 707 objectclass: top
 708 objectclass: dnsdomain
 709 objectclass: domainrelatedobject
 710 dc: tjener
 711 arecord: 10.0.2.2
 712 associateddomain: tjener.intern
 713
 714 dn: dc=2,dc=2,dc=0,dc=10,dc=in-addr,dc=arpa,ou=hosts,dc=skole,dc=skolelinux,dc=no
 715 objectclass: top
 716 objectclass: dnsdomain2
 717 objectclass: domainrelatedobject
 718 dc: 2
 719 ptrrecord: tjener.intern
 720 associateddomain: 2.2.0.10.in-addr.arpa
 721 </pre></blockquote>
 722
 723 <p>In strict mode, the server behaves differently.  When looking for
 724 forward DNS entries, it is doing a "subtree" scoped search with the
 725 same base as in the tree mode for a object with filter
 726 "(associateddomain=tjener.intern)" and requests the attributes dnsttl,
 727 arecord, nsrecord, cnamerecord, soarecord, ptrrecord, hinforecord,
 728 mxrecord, txtrecord, rprecord, aaaarecord, locrecord, srvrecord,
 729 naptrrecord and modifytimestamp.  For reverse entires it also do a
 730 subtree scoped search but this time the filter is "(arecord=10.0.2.2)"
 731 and the requested attributes are associateddomain, dnsttl and
 732 modifytimestamp.  In short, in strict mode the objects with ptrrecord
 733 go away, and the arecord attribute in the forward object is used
 734 instead.</p>
 735
 736 <p>The forward and reverse searches can be simulated using ldapsearch
 737 like this:</p>
 738
 739 <blockquote><pre>
 740 ldapsearch -h ldap -b ou=hosts,dc=skole,dc=skolelinux,dc=no -s sub -x \
 741   '(associateddomain=tjener.intern)' dNSTTL aRecord nSRecord \
 742   cNAMERecord sOARecord pTRRecord hInfoRecord mXRecord tXTRecord \
 743   rPRecord aFSDBRecord KeyRecord aAAARecord lOCRecord sRVRecord \
 744   nAPTRRecord kXRecord certRecord dSRecord sSHFPRecord iPSecKeyRecord \
 745   rRSIGRecord nSECRecord dNSKeyRecord dHCIDRecord sPFRecord modifyTimestamp
 746
 747 ldapsearch -h ldap -b ou=hosts,dc=skole,dc=skolelinux,dc=no -s sub -x \
 748   '(arecord=10.0.2.2)' associateddomain dnsttl modifytimestamp
 749 </pre></blockquote>
 750
 751 <p>In addition to the forward and reverse searches , there is also a
 752 search for SOA records, which behave similar to the forward and
 753 reverse lookups.</p>
 754
 755 <p>A thing to note with the PowerDNS behaviour is that it do not
 756 specify any objectclass names, and instead look for the attributes it
 757 need to generate a DNS reply.  This make it able to work with any
 758 objectclass that provide the needed attributes.</p>
 759
 760 <p>The attributes are normally provided in the cosine (RFC 1274) and
 761 dnsdomain2 schemas.  The latter is used for reverse entries like
 762 ptrrecord and recent DNS additions like aaaarecord and srvrecord.</p>
 763
 764 <p>In Debian Edu, we have created DNS objects using the object classes
 765 dcobject (for dc), dnsdomain or dnsdomain2 (structural, for the DNS
 766 attributes) and domainrelatedobject (for associatedDomain).  The use
 767 of structural object classes make it impossible to combine these
 768 classes with the object classes used by DHCP.</p>
 769
 770 <p>There are other schemas that could be used too, for example the
 771 dnszone structural object class used by Gosa and bind-sdb for the DNS
 772 attributes combined with the domainrelatedobject object class, but in
 773 this case some unused attributes would have to be included as well
 774 (zonename and relativedomainname).</p>
 775
 776 <p>My proposal for Debian Edu would be to switch PowerDNS to strict
 777 mode and not use any of the existing objectclasses (dnsdomain,
 778 dnsdomain2 and dnszone) when one want to combine the DNS information
 779 with DHCP information, and instead create a auxiliary object class
 780 defined something like this (using the attributes defined for
 781 dnsdomain and dnsdomain2 or dnszone):</p>
 782
 783 <blockquote><pre>
 784 objectclass ( some-oid NAME 'dnsDomainAux'
 785     SUP top
 786     AUXILIARY
 787     MAY ( ARecord $ MDRecord $ MXRecord $ NSRecord $ SOARecord $ CNAMERecord $
 788           DNSTTL $ DNSClass $ PTRRecord $ HINFORecord $ MINFORecord $
 789           TXTRecord $ SIGRecord $ KEYRecord $ AAAARecord $ LOCRecord $
 790           NXTRecord $ SRVRecord $ NAPTRRecord $ KXRecord $ CERTRecord $
 791           A6Record $ DNAMERecord
 792     ))
 793 </pre></blockquote>
 794
 795 <p>This will allow any object to become a DNS entry when combined with
 796 the domainrelatedobject object class, and allow any entity to include
 797 all the attributes PowerDNS wants.  I've sent an email to the PowerDNS
 798 developers asking for their view on this schema and if they are
 799 interested in providing such schema with PowerDNS, and I hope my
 800 message will be accepted into their mailing list soon.</p>
 801
 802 <p><strong>ISC dhcp</strong></p>
 803
 804 <p>The DHCP server searches for specific objectclass and requests all
 805 the object attributes, and then uses the attributes it want.  This
 806 make it harder to figure out exactly what attributes are used, but
 807 thanks to the working example in Debian Edu I can at least get an idea
 808 what is needed without having to read the source code.</p>
 809
 810 <p>In the DHCP server configuration, the LDAP base to use and the
 811 search filter to use to locate the correct dhcpServer entity is
 812 stored.  These are the relevant entries from
 813 /etc/dhcp3/dhcpd.conf:</p>
 814
 815 <blockquote><pre>
 816 ldap-base-dn "dc=skole,dc=skolelinux,dc=no";
 817 ldap-dhcp-server-cn "dhcp";
 818 </pre></blockquote>
 819
 820 <p>The DHCP server uses this information to nest all the DHCP
 821 configuration it need.  The cn "dhcp" is located using the given LDAP
 822 base and the filter "(&(objectClass=dhcpServer)(cn=dhcp))".  The
 823 search result is this entry:</p>
 824
 825 <blockquote><pre>
 826 dn: cn=dhcp,dc=skole,dc=skolelinux,dc=no
 827 cn: dhcp
 828 objectClass: top
 829 objectClass: dhcpServer
 830 dhcpServiceDN: cn=DHCP Config,dc=skole,dc=skolelinux,dc=no
 831 </pre></blockquote>
 832
 833 <p>The content of the dhcpServiceDN attribute is next used to locate the
 834 subtree with DHCP configuration.  The DHCP configuration subtree base
 835 is located using a base scope search with base "cn=DHCP
 836 Config,dc=skole,dc=skolelinux,dc=no" and filter
 837 "(&(objectClass=dhcpService)(|(dhcpPrimaryDN=cn=dhcp,dc=skole,dc=skolelinux,dc=no)(dhcpSecondaryDN=cn=dhcp,dc=skole,dc=skolelinux,dc=no)))".
 838 The search result is this entry:</p>
 839
 840 <blockquote><pre>
 841 dn: cn=DHCP Config,dc=skole,dc=skolelinux,dc=no
 842 cn: DHCP Config
 843 objectClass: top
 844 objectClass: dhcpService
 845 objectClass: dhcpOptions
 846 dhcpPrimaryDN: cn=dhcp, dc=skole,dc=skolelinux,dc=no
 847 dhcpStatements: ddns-update-style none
 848 dhcpStatements: authoritative
 849 dhcpOption: smtp-server code 69 = array of ip-address
 850 dhcpOption: www-server code 72 = array of ip-address
 851 dhcpOption: wpad-url code 252 = text
 852 </pre></blockquote>
 853
 854 <p>Next, the entire subtree is processed, one level at the time.  When
 855 all the DHCP configuration is loaded, it is ready to receive requests.
 856 The subtree in Debian Edu contain objects with object classes
 857 top/dhcpService/dhcpOptions, top/dhcpSharedNetwork/dhcpOptions,
 858 top/dhcpSubnet, top/dhcpGroup and top/dhcpHost.  These provide options
 859 and information about netmasks, dynamic range etc.  Leaving out the
 860 details here because it is not relevant for the focus of my
 861 investigation, which is to see if it is possible to merge dns and dhcp
 862 related computer objects.</p>
 863
 864 <p>When a DHCP request come in, LDAP is searched for the MAC address
 865 of the client (00:00:00:00:00:00 in this example), using a subtree
 866 scoped search with "cn=DHCP Config,dc=skole,dc=skolelinux,dc=no" as
 867 the base and "(&(objectClass=dhcpHost)(dhcpHWAddress=ethernet
 868 00:00:00:00:00:00))" as the filter.  This is what a host object look
 869 like:</p>
 870
 871 <blockquote><pre>
 872 dn: cn=hostname,cn=group1,cn=THINCLIENTS,cn=DHCP Config,dc=skole,dc=skolelinux,dc=no
 873 cn: hostname
 874 objectClass: top
 875 objectClass: dhcpHost
 876 dhcpHWAddress: ethernet 00:00:00:00:00:00
 877 dhcpStatements: fixed-address hostname
 878 </pre></blockquote>
 879
 880 <p>There is less flexiblity in the way LDAP searches are done here.
 881 The object classes need to have fixed names, and the configuration
 882 need to be stored in a fairly specific LDAP structure.  On the
 883 positive side, the invidiual dhcpHost entires can be anywhere without
 884 the DN pointed to by the dhcpServer entries.  The latter should make
 885 it possible to group all host entries in a subtree next to the
 886 configuration entries, and this subtree can also be shared with the
 887 DNS server if the schema proposed above is combined with the dhcpHost
 888 structural object class.
 889
 890 <p><strong>Conclusion</strong></p>
 891
 892 <p>The PowerDNS implementation seem to be very flexible when it come
 893 to which LDAP schemas to use.  While its "tree" mode is rigid when it
 894 come to the the LDAP structure, the "strict" mode is very flexible,
 895 allowing DNS objects to be stored anywhere under the base cn specified
 896 in the configuration.</p>
 897
 898 <p>The DHCP implementation on the other hand is very inflexible, both
 899 regarding which LDAP schemas to use and which LDAP structure to use.
 900 I guess one could implement ones own schema, as long as the
 901 objectclasses and attributes have the names used, but this do not
 902 really help when the DHCP subtree need to have a fairly fixed
 903 structure.</p>
 904
 905 <p>Based on the observed behaviour, I suspect a LDAP structure like
 906 this might work for Debian Edu:</p>
 907
 908 <blockquote><pre>
 909 ou=services
 910   cn=machine-info (dhcpService) - dhcpServiceDN points here
 911     cn=dhcp (dhcpServer)
 912     cn=dhcp-internal (dhcpSharedNetwork/dhcpOptions)
 913       cn=10.0.2.0 (dhcpSubnet)
 914         cn=group1 (dhcpGroup/dhcpOptions)
 915     cn=dhcp-thinclients (dhcpSharedNetwork/dhcpOptions)
 916       cn=192.168.0.0 (dhcpSubnet)
 917         cn=group1 (dhcpGroup/dhcpOptions)
 918     ou=machines - PowerDNS base points here
 919       cn=hostname (dhcpHost/domainrelatedobject/dnsDomainAux)
 920 </pre></blockquote>
 921
 922 <P>This is not tested yet.  If the DHCP server require the dhcpHost
 923 entries to be in the dhcpGroup subtrees, the entries can be stored
 924 there instead of a common machines subtree, and the PowerDNS base
 925 would have to be moved one level up to the machine-info subtree.</p>
 926
 927 <p>The combined object under the machines subtree would look something
 928 like this:</p>
 929
 930 <blockquote><pre>
 931 dn: dc=hostname,ou=machines,cn=machine-info,dc=skole,dc=skolelinux,dc=no
 932 dc: hostname
 933 objectClass: top
 934 objectClass: dhcpHost
 935 objectclass: domainrelatedobject
 936 objectclass: dnsDomainAux
 937 associateddomain: hostname.intern
 938 arecord: 10.11.12.13
 939 dhcpHWAddress: ethernet 00:00:00:00:00:00
 940 dhcpStatements: fixed-address hostname.intern
 941 </pre></blockquote>
 942
 943 </p>One could even add the LTSP configuration associated with a given
 944 machine, as long as the required attributes are available in a
 945 auxiliary object class.</p>
 946
 947  </div>
 948  <div class="tags">
 949
 950
 951
 952   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>.
 953
 954  </div>
 955 </div>
 956 <div class="padding"></div>
 957
 958  <p style="text-align: right;"><a href="ldap.rss"><img src="http://people.skolelinux.org/pere/blog/xml.gif" alt="RSS Feed" width="36" height="14"></a></p>
 959
 960
 961
 962
 963 <div id="sidebar">
 964
 965 <h2>Archive</h2>
 966 <ul>
 967
 968 <li>2010
 969 <ul>
 970
 971 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/01/">January (2)</a></li>
 972
 973 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/02/">February (1)</a></li>
 974
 975 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/03/">March (3)</a></li>
 976
 977 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/04/">April (3)</a></li>
 978
 979 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/05/">May (9)</a></li>
 980
 981 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/06/">June (14)</a></li>
 982
 983 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/07/">July (12)</a></li>
 984
 985 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/08/">August (13)</a></li>
 986
 987 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/09/">September (7)</a></li>
 988
 989 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/10/">October (9)</a></li>
 990
 991 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/11/">November (12)</a></li>
 992
 993 </ul></li>
 994
 995 <li>2009
 996 <ul>
 997
 998 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/01/">January (8)</a></li>
 999
1000 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/02/">February (8)</a></li>
1001
1002 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/03/">March (12)</a></li>
1003
1004 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/04/">April (10)</a></li>
1005
1006 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/05/">May (9)</a></li>
1007
1008 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/06/">June (3)</a></li>
1009
1010 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/07/">July (4)</a></li>
1011
1012 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/08/">August (3)</a></li>
1013
1014 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/09/">September (1)</a></li>
1015
1016 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/10/">October (2)</a></li>
1017
1018 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/11/">November (3)</a></li>
1019
1020 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/12/">December (3)</a></li>
1021
1022 </ul></li>
1023
1024 <li>2008
1025 <ul>
1026
1027 <li><a href="http://people.skolelinux.org/pere/blog/archive/2008/11/">November (5)</a></li>
1028
1029 <li><a href="http://people.skolelinux.org/pere/blog/archive/2008/12/">December (7)</a></li>
1030
1031 </ul></li>
1032
1033 </ul>
1034
1035
1036
1037 <h2>Tags</h2>
1038 <ul>
1039
1040  <li><a href="http://people.skolelinux.org/pere/blog/tags/3d-printer">3d-printer (12)</a></li>
1041
1042  <li><a href="http://people.skolelinux.org/pere/blog/tags/amiga">amiga (1)</a></li>
1043
1044  <li><a href="http://people.skolelinux.org/pere/blog/tags/aros">aros (1)</a></li>
1045
1046  <li><a href="http://people.skolelinux.org/pere/blog/tags/bootsystem">bootsystem (10)</a></li>
1047
1048  <li><a href="http://people.skolelinux.org/pere/blog/tags/debian">debian (43)</a></li>
1049
1050  <li><a href="http://people.skolelinux.org/pere/blog/tags/debian edu">debian edu (51)</a></li>
1051
1052  <li><a href="http://people.skolelinux.org/pere/blog/tags/english">english (72)</a></li>
1053
1054  <li><a href="http://people.skolelinux.org/pere/blog/tags/fiksgatami">fiksgatami (1)</a></li>
1055
1056  <li><a href="http://people.skolelinux.org/pere/blog/tags/fildeling">fildeling (11)</a></li>
1057
1058  <li><a href="http://people.skolelinux.org/pere/blog/tags/kart">kart (5)</a></li>
1059
1060  <li><a href="http://people.skolelinux.org/pere/blog/tags/ldap">ldap (8)</a></li>
1061
1062  <li><a href="http://people.skolelinux.org/pere/blog/tags/lenker">lenker (4)</a></li>
1063
1064  <li><a href="http://people.skolelinux.org/pere/blog/tags/ltsp">ltsp (1)</a></li>
1065
1066  <li><a href="http://people.skolelinux.org/pere/blog/tags/multimedia">multimedia (11)</a></li>
1067
1068  <li><a href="http://people.skolelinux.org/pere/blog/tags/norsk">norsk (91)</a></li>
1069
1070  <li><a href="http://people.skolelinux.org/pere/blog/tags/nuug">nuug (113)</a></li>
1071
1072  <li><a href="http://people.skolelinux.org/pere/blog/tags/opphavsrett">opphavsrett (18)</a></li>
1073
1074  <li><a href="http://people.skolelinux.org/pere/blog/tags/personvern">personvern (26)</a></li>
1075
1076  <li><a href="http://people.skolelinux.org/pere/blog/tags/reprap">reprap (10)</a></li>
1077
1078  <li><a href="http://people.skolelinux.org/pere/blog/tags/robot">robot (4)</a></li>
1079
1080  <li><a href="http://people.skolelinux.org/pere/blog/tags/rss">rss (1)</a></li>
1081
1082  <li><a href="http://people.skolelinux.org/pere/blog/tags/sikkerhet">sikkerhet (19)</a></li>
1083
1084  <li><a href="http://people.skolelinux.org/pere/blog/tags/sitesummary">sitesummary (3)</a></li>
1085
1086  <li><a href="http://people.skolelinux.org/pere/blog/tags/standard">standard (16)</a></li>
1087
1088  <li><a href="http://people.skolelinux.org/pere/blog/tags/stavekontroll">stavekontroll (1)</a></li>
1089
1090  <li><a href="http://people.skolelinux.org/pere/blog/tags/video">video (16)</a></li>
1091
1092  <li><a href="http://people.skolelinux.org/pere/blog/tags/vitenskap">vitenskap (1)</a></li>
1093
1094  <li><a href="http://people.skolelinux.org/pere/blog/tags/web">web (14)</a></li>
1095
1096 </ul>
1097
1098 </div>
1099 </body>
1100 </html>