blog/What_are_they_searching_for___PowerDNS_and_ISC_DHCP_in_LDAP.html

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  14  <h1>
  15      <a href="http://people.skolelinux.org/pere/blog/">Petter Reinholdtsen</a>
  16
  17  </h1>
  18
  19 </div>
  20
  21
  22     <div class="entry">
  23       <div class="title">What are they searching for - PowerDNS and ISC DHCP in LDAP</div>
  24       <div class="date">17th July 2010</div>
  25       <div class="body"><p>This is a
  26 <a href="http://people.skolelinux.org/pere/blog/Time_for_new__LDAP_schemas_replacing_RFC_2307_.html">followup</a>
  27 on my
  28 <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
  29 work</a> on
  30 <a href="http://people.skolelinux.org/pere/blog/Combining_PowerDNS_and_ISC_DHCP_LDAP_objects.html">merging
  31 all</a> the computer related LDAP objects in Debian Edu.</p>
  32
  33 <p>As a step to try to see if it possible to merge the DNS and DHCP
  34 LDAP objects, I have had a look at how the packages pdns-backend-ldap
  35 and dhcp3-server-ldap in Debian use the LDAP server.  The two
  36 implementations are quite different in how they use LDAP.</p>
  37
  38 To get this information, I started slapd with debugging enabled and
  39 dumped the debug output to a file to get the LDAP searches performed
  40 on a Debian Edu main-server.  Here is a summary.
  41
  42 <p><strong>powerdns</strong></p>
  43
  44 <a href="http://www.linuxnetworks.de/doc/index.php/PowerDNS_LDAP_Backend">Clues
  45 on how to</a> set up PowerDNS to use a LDAP backend is available on
  46 the web.
  47
  48 <p>PowerDNS have two modes of operation using LDAP as its backend.
  49 One "strict" mode where the forward and reverse DNS lookups are done
  50 using the same LDAP objects, and a "tree" mode where the forward and
  51 reverse entries are in two different subtrees in LDAP with a structure
  52 based on the DNS names, as in tjener.intern and
  53 2.2.0.10.in-addr.arpa.</p>
  54
  55 <p>In tree mode, the server is set up to use a LDAP subtree as its
  56 base, and uses a "base" scoped search for the DNS name by adding
  57 "dc=tjener,dc=intern," to the base with a filter for
  58 "(associateddomain=tjener.intern)" for the forward entry and
  59 "dc=2,dc=2,dc=0,dc=10,dc=in-addr,dc=arpa," with a filter for
  60 "(associateddomain=2.2.0.10.in-addr.arpa)" for the reverse entry.  For
  61 forward entries, it is looking for attributes named dnsttl, arecord,
  62 nsrecord, cnamerecord, soarecord, ptrrecord, hinforecord, mxrecord,
  63 txtrecord, rprecord, afsdbrecord, keyrecord, aaaarecord, locrecord,
  64 srvrecord, naptrrecord, kxrecord, certrecord, dsrecord, sshfprecord,
  65 ipseckeyrecord, rrsigrecord, nsecrecord, dnskeyrecord, dhcidrecord,
  66 spfrecord and modifytimestamp.  For reverse entries it is looking for
  67 the attributes dnsttl, arecord, nsrecord, cnamerecord, soarecord,
  68 ptrrecord, hinforecord, mxrecord, txtrecord, rprecord, aaaarecord,
  69 locrecord, srvrecord, naptrrecord and modifytimestamp.  The equivalent
  70 ldapsearch commands could look like this:</p>
  71
  72 <blockquote><pre>
  73 ldapsearch -h ldap \
  74   -b dc=tjener,dc=intern,ou=hosts,dc=skole,dc=skolelinux,dc=no \
  75   -s base -x '(associateddomain=tjener.intern)' dNSTTL aRecord nSRecord \
  76   cNAMERecord sOARecord pTRRecord hInfoRecord mXRecord tXTRecord \
  77   rPRecord aFSDBRecord KeyRecord aAAARecord lOCRecord sRVRecord \
  78   nAPTRRecord kXRecord certRecord dSRecord sSHFPRecord iPSecKeyRecord \
  79   rRSIGRecord nSECRecord dNSKeyRecord dHCIDRecord sPFRecord modifyTimestamp
  80
  81 ldapsearch -h ldap \
  82   -b dc=2,dc=2,dc=0,dc=10,dc=in-addr,dc=arpa,ou=hosts,dc=skole,dc=skolelinux,dc=no \
  83   -s base -x '(associateddomain=2.2.0.10.in-addr.arpa)'
  84   dnsttl, arecord, nsrecord, cnamerecord soarecord ptrrecord \
  85   hinforecord mxrecord txtrecord rprecord aaaarecord locrecord \
  86   srvrecord naptrrecord modifytimestamp
  87 </pre></blockquote>
  88
  89 <p>In Debian Edu/Lenny, the PowerDNS tree mode is used with
  90 ou=hosts,dc=skole,dc=skolelinux,dc=no as the base, and these are two
  91 example LDAP objects used there.  In addition to these objects, the
  92 parent objects all th way up to ou=hosts,dc=skole,dc=skolelinux,dc=no
  93 also exist.</p>
  94
  95 <blockquote><pre>
  96 dn: dc=tjener,dc=intern,ou=hosts,dc=skole,dc=skolelinux,dc=no
  97 objectclass: top
  98 objectclass: dnsdomain
  99 objectclass: domainrelatedobject
 100 dc: tjener
 101 arecord: 10.0.2.2
 102 associateddomain: tjener.intern
 103
 104 dn: dc=2,dc=2,dc=0,dc=10,dc=in-addr,dc=arpa,ou=hosts,dc=skole,dc=skolelinux,dc=no
 105 objectclass: top
 106 objectclass: dnsdomain2
 107 objectclass: domainrelatedobject
 108 dc: 2
 109 ptrrecord: tjener.intern
 110 associateddomain: 2.2.0.10.in-addr.arpa
 111 </pre></blockquote>
 112
 113 <p>In strict mode, the server behaves differently.  When looking for
 114 forward DNS entries, it is doing a "subtree" scoped search with the
 115 same base as in the tree mode for a object with filter
 116 "(associateddomain=tjener.intern)" and requests the attributes dnsttl,
 117 arecord, nsrecord, cnamerecord, soarecord, ptrrecord, hinforecord,
 118 mxrecord, txtrecord, rprecord, aaaarecord, locrecord, srvrecord,
 119 naptrrecord and modifytimestamp.  For reverse entires it also do a
 120 subtree scoped search but this time the filter is "(arecord=10.0.2.2)"
 121 and the requested attributes are associateddomain, dnsttl and
 122 modifytimestamp.  In short, in strict mode the objects with ptrrecord
 123 go away, and the arecord attribute in the forward object is used
 124 instead.</p>
 125
 126 <p>The forward and reverse searches can be simulated using ldapsearch
 127 like this:</p>
 128
 129 <blockquote><pre>
 130 ldapsearch -h ldap -b ou=hosts,dc=skole,dc=skolelinux,dc=no -s sub -x \
 131   '(associateddomain=tjener.intern)' dNSTTL aRecord nSRecord \
 132   cNAMERecord sOARecord pTRRecord hInfoRecord mXRecord tXTRecord \
 133   rPRecord aFSDBRecord KeyRecord aAAARecord lOCRecord sRVRecord \
 134   nAPTRRecord kXRecord certRecord dSRecord sSHFPRecord iPSecKeyRecord \
 135   rRSIGRecord nSECRecord dNSKeyRecord dHCIDRecord sPFRecord modifyTimestamp
 136
 137 ldapsearch -h ldap -b ou=hosts,dc=skole,dc=skolelinux,dc=no -s sub -x \
 138   '(arecord=10.0.2.2)' associateddomain dnsttl modifytimestamp
 139 </pre></blockquote>
 140
 141 <p>In addition to the forward and reverse searches , there is also a
 142 search for SOA records, which behave similar to the forward and
 143 reverse lookups.</p>
 144
 145 <p>A thing to note with the PowerDNS behaviour is that it do not
 146 specify any objectclass names, and instead look for the attributes it
 147 need to generate a DNS reply.  This make it able to work with any
 148 objectclass that provide the needed attributes.</p>
 149
 150 <p>The attributes are normally provided in the cosine (RFC 1274) and
 151 dnsdomain2 schemas.  The latter is used for reverse entries like
 152 ptrrecord and recent DNS additions like aaaarecord and srvrecord.</p>
 153
 154 <p>In Debian Edu, we have created DNS objects using the object classes
 155 dcobject (for dc), dnsdomain or dnsdomain2 (structural, for the DNS
 156 attributes) and domainrelatedobject (for associatedDomain).  The use
 157 of structural object classes make it impossible to combine these
 158 classes with the object classes used by DHCP.</p>
 159
 160 <p>There are other schemas that could be used too, for example the
 161 dnszone structural object class used by Gosa and bind-sdb for the DNS
 162 attributes combined with the domainrelatedobject object class, but in
 163 this case some unused attributes would have to be included as well
 164 (zonename and relativedomainname).</p>
 165
 166 <p>My proposal for Debian Edu would be to switch PowerDNS to strict
 167 mode and not use any of the existing objectclasses (dnsdomain,
 168 dnsdomain2 and dnszone) when one want to combine the DNS information
 169 with DHCP information, and instead create a auxiliary object class
 170 defined something like this (using the attributes defined for
 171 dnsdomain and dnsdomain2 or dnszone):</p>
 172
 173 <blockquote><pre>
 174 objectclass ( some-oid NAME 'dnsDomainAux'
 175     SUP top
 176     AUXILIARY
 177     MAY ( ARecord $ MDRecord $ MXRecord $ NSRecord $ SOARecord $ CNAMERecord $
 178           DNSTTL $ DNSClass $ PTRRecord $ HINFORecord $ MINFORecord $
 179           TXTRecord $ SIGRecord $ KEYRecord $ AAAARecord $ LOCRecord $
 180           NXTRecord $ SRVRecord $ NAPTRRecord $ KXRecord $ CERTRecord $
 181           A6Record $ DNAMERecord
 182     ))
 183 </pre></blockquote>
 184
 185 <p>This will allow any object to become a DNS entry when combined with
 186 the domainrelatedobject object class, and allow any entity to include
 187 all the attributes PowerDNS wants.  I've sent an email to the PowerDNS
 188 developers asking for their view on this schema and if they are
 189 interested in providing such schema with PowerDNS, and I hope my
 190 message will be accepted into their mailing list soon.</p>
 191
 192 <p><strong>ISC dhcp</strong></p>
 193
 194 <p>The DHCP server searches for specific objectclass and requests all
 195 the object attributes, and then uses the attributes it want.  This
 196 make it harder to figure out exactly what attributes are used, but
 197 thanks to the working example in Debian Edu I can at least get an idea
 198 what is needed without having to read the source code.</p>
 199
 200 <p>In the DHCP server configuration, the LDAP base to use and the
 201 search filter to use to locate the correct dhcpServer entity is
 202 stored.  These are the relevant entries from
 203 /etc/dhcp3/dhcpd.conf:</p>
 204
 205 <blockquote><pre>
 206 ldap-base-dn "dc=skole,dc=skolelinux,dc=no";
 207 ldap-dhcp-server-cn "dhcp";
 208 </pre></blockquote>
 209
 210 <p>The DHCP server uses this information to nest all the DHCP
 211 configuration it need.  The cn "dhcp" is located using the given LDAP
 212 base and the filter "(&(objectClass=dhcpServer)(cn=dhcp))".  The
 213 search result is this entry:</p>
 214
 215 <blockquote><pre>
 216 dn: cn=dhcp,dc=skole,dc=skolelinux,dc=no
 217 cn: dhcp
 218 objectClass: top
 219 objectClass: dhcpServer
 220 dhcpServiceDN: cn=DHCP Config,dc=skole,dc=skolelinux,dc=no
 221 </pre></blockquote>
 222
 223 <p>The content of the dhcpServiceDN attribute is next used to locate the
 224 subtree with DHCP configuration.  The DHCP configuration subtree base
 225 is located using a base scope search with base "cn=DHCP
 226 Config,dc=skole,dc=skolelinux,dc=no" and filter
 227 "(&(objectClass=dhcpService)(|(dhcpPrimaryDN=cn=dhcp,dc=skole,dc=skolelinux,dc=no)(dhcpSecondaryDN=cn=dhcp,dc=skole,dc=skolelinux,dc=no)))".
 228 The search result is this entry:</p>
 229
 230 <blockquote><pre>
 231 dn: cn=DHCP Config,dc=skole,dc=skolelinux,dc=no
 232 cn: DHCP Config
 233 objectClass: top
 234 objectClass: dhcpService
 235 objectClass: dhcpOptions
 236 dhcpPrimaryDN: cn=dhcp, dc=skole,dc=skolelinux,dc=no
 237 dhcpStatements: ddns-update-style none
 238 dhcpStatements: authoritative
 239 dhcpOption: smtp-server code 69 = array of ip-address
 240 dhcpOption: www-server code 72 = array of ip-address
 241 dhcpOption: wpad-url code 252 = text
 242 </pre></blockquote>
 243
 244 <p>Next, the entire subtree is processed, one level at the time.  When
 245 all the DHCP configuration is loaded, it is ready to receive requests.
 246 The subtree in Debian Edu contain objects with object classes
 247 top/dhcpService/dhcpOptions, top/dhcpSharedNetwork/dhcpOptions,
 248 top/dhcpSubnet, top/dhcpGroup and top/dhcpHost.  These provide options
 249 and information about netmasks, dynamic range etc.  Leaving out the
 250 details here because it is not relevant for the focus of my
 251 investigation, which is to see if it is possible to merge dns and dhcp
 252 related computer objects.</p>
 253
 254 <p>When a DHCP request come in, LDAP is searched for the MAC address
 255 of the client (00:00:00:00:00:00 in this example), using a subtree
 256 scoped search with "cn=DHCP Config,dc=skole,dc=skolelinux,dc=no" as
 257 the base and "(&(objectClass=dhcpHost)(dhcpHWAddress=ethernet
 258 00:00:00:00:00:00))" as the filter.  This is what a host object look
 259 like:</p>
 260
 261 <blockquote><pre>
 262 dn: cn=hostname,cn=group1,cn=THINCLIENTS,cn=DHCP Config,dc=skole,dc=skolelinux,dc=no
 263 cn: hostname
 264 objectClass: top
 265 objectClass: dhcpHost
 266 dhcpHWAddress: ethernet 00:00:00:00:00:00
 267 dhcpStatements: fixed-address hostname
 268 </pre></blockquote>
 269
 270 <p>There is less flexiblity in the way LDAP searches are done here.
 271 The object classes need to have fixed names, and the configuration
 272 need to be stored in a fairly specific LDAP structure.  On the
 273 positive side, the invidiual dhcpHost entires can be anywhere without
 274 the DN pointed to by the dhcpServer entries.  The latter should make
 275 it possible to group all host entries in a subtree next to the
 276 configuration entries, and this subtree can also be shared with the
 277 DNS server if the schema proposed above is combined with the dhcpHost
 278 structural object class.
 279
 280 <p><strong>Conclusion</strong></p>
 281
 282 <p>The PowerDNS implementation seem to be very flexible when it come
 283 to which LDAP schemas to use.  While its "tree" mode is rigid when it
 284 come to the the LDAP structure, the "strict" mode is very flexible,
 285 allowing DNS objects to be stored anywhere under the base cn specified
 286 in the configuration.</p>
 287
 288 <p>The DHCP implementation on the other hand is very inflexible, both
 289 regarding which LDAP schemas to use and which LDAP structure to use.
 290 I guess one could implement ones own schema, as long as the
 291 objectclasses and attributes have the names used, but this do not
 292 really help when the DHCP subtree need to have a fairly fixed
 293 structure.</p>
 294
 295 <p>Based on the observed behaviour, I suspect a LDAP structure like
 296 this might work for Debian Edu:</p>
 297
 298 <blockquote><pre>
 299 ou=services
 300   cn=machine-info (dhcpService) - dhcpServiceDN points here
 301     cn=dhcp (dhcpServer)
 302     cn=dhcp-internal (dhcpSharedNetwork/dhcpOptions)
 303       cn=10.0.2.0 (dhcpSubnet)
 304         cn=group1 (dhcpGroup/dhcpOptions)
 305     cn=dhcp-thinclients (dhcpSharedNetwork/dhcpOptions)
 306       cn=192.168.0.0 (dhcpSubnet)
 307         cn=group1 (dhcpGroup/dhcpOptions)
 308     ou=machines - PowerDNS base points here
 309       cn=hostname (dhcpHost/domainrelatedobject/dnsDomainAux)
 310 </pre></blockquote>
 311
 312 <P>This is not tested yet.  If the DHCP server require the dhcpHost
 313 entries to be in the dhcpGroup subtrees, the entries can be stored
 314 there instead of a common machines subtree, and the PowerDNS base
 315 would have to be moved one level up to the machine-info subtree.</p>
 316
 317 <p>The combined object under the machines subtree would look something
 318 like this:</p>
 319
 320 <blockquote><pre>
 321 dn: dc=hostname,ou=machines,cn=machine-info,dc=skole,dc=skolelinux,dc=no
 322 dc: hostname
 323 objectClass: top
 324 objectClass: dhcpHost
 325 objectclass: domainrelatedobject
 326 objectclass: dnsDomainAux
 327 associateddomain: hostname.intern
 328 arecord: 10.11.12.13
 329 dhcpHWAddress: ethernet 00:00:00:00:00:00
 330 dhcpStatements: fixed-address hostname.intern
 331 </pre></blockquote>
 332
 333 </p>One could even add the LTSP configuration associated with a given
 334 machine, as long as the required attributes are available in a
 335 auxiliary object class.</p>
 336 </div>
 337
 338       <div class="tags">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>.</div>
 339
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 341     </div>
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 350 <h2>Archive</h2>
 351 <ul>
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 377
 378 <li>2012
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 381 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/01/">January (7)</a></li>
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 403 <li><a href="http://people.skolelinux.org/pere/blog/archive/2012/12/">December (7)</a></li>
 404
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 406
 407 <li>2011
 408 <ul>
 409
 410 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/01/">January (16)</a></li>
 411
 412 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/02/">February (6)</a></li>
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 414 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/03/">March (6)</a></li>
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 431
 432 <li><a href="http://people.skolelinux.org/pere/blog/archive/2011/12/">December (1)</a></li>
 433
 434 </ul></li>
 435
 436 <li>2010
 437 <ul>
 438
 439 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/01/">January (2)</a></li>
 440
 441 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/02/">February (1)</a></li>
 442
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 459 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/11/">November (13)</a></li>
 460
 461 <li><a href="http://people.skolelinux.org/pere/blog/archive/2010/12/">December (12)</a></li>
 462
 463 </ul></li>
 464
 465 <li>2009
 466 <ul>
 467
 468 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/01/">January (8)</a></li>
 469
 470 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/02/">February (8)</a></li>
 471
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 473
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 475
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 477
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 479
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 481
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 483
 484 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/09/">September (1)</a></li>
 485
 486 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/10/">October (2)</a></li>
 487
 488 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/11/">November (3)</a></li>
 489
 490 <li><a href="http://people.skolelinux.org/pere/blog/archive/2009/12/">December (3)</a></li>
 491
 492 </ul></li>
 493
 494 <li>2008
 495 <ul>
 496
 497 <li><a href="http://people.skolelinux.org/pere/blog/archive/2008/11/">November (5)</a></li>
 498
 499 <li><a href="http://people.skolelinux.org/pere/blog/archive/2008/12/">December (7)</a></li>
 500
 501 </ul></li>
 502
 503 </ul>
 504
 505
 506
 507 <h2>Tags</h2>
 508 <ul>
 509
 510  <li><a href="http://people.skolelinux.org/pere/blog/tags/3d-printer">3d-printer (13)</a></li>
 511
 512  <li><a href="http://people.skolelinux.org/pere/blog/tags/amiga">amiga (1)</a></li>
 513
 514  <li><a href="http://people.skolelinux.org/pere/blog/tags/aros">aros (1)</a></li>
 515
 516  <li><a href="http://people.skolelinux.org/pere/blog/tags/bankid">bankid (4)</a></li>
 517
 518  <li><a href="http://people.skolelinux.org/pere/blog/tags/bitcoin">bitcoin (7)</a></li>
 519
 520  <li><a href="http://people.skolelinux.org/pere/blog/tags/bootsystem">bootsystem (12)</a></li>
 521
 522  <li><a href="http://people.skolelinux.org/pere/blog/tags/bsa">bsa (2)</a></li>
 523
 524  <li><a href="http://people.skolelinux.org/pere/blog/tags/debian">debian (87)</a></li>
 525
 526  <li><a href="http://people.skolelinux.org/pere/blog/tags/debian edu">debian edu (142)</a></li>
 527
 528  <li><a href="http://people.skolelinux.org/pere/blog/tags/digistan">digistan (10)</a></li>
 529
 530  <li><a href="http://people.skolelinux.org/pere/blog/tags/docbook">docbook (10)</a></li>
 531
 532  <li><a href="http://people.skolelinux.org/pere/blog/tags/drivstoffpriser">drivstoffpriser (4)</a></li>
 533
 534  <li><a href="http://people.skolelinux.org/pere/blog/tags/english">english (222)</a></li>
 535
 536  <li><a href="http://people.skolelinux.org/pere/blog/tags/fiksgatami">fiksgatami (21)</a></li>
 537
 538  <li><a href="http://people.skolelinux.org/pere/blog/tags/fildeling">fildeling (12)</a></li>
 539
 540  <li><a href="http://people.skolelinux.org/pere/blog/tags/freeculture">freeculture (12)</a></li>
 541
 542  <li><a href="http://people.skolelinux.org/pere/blog/tags/freedombox">freedombox (4)</a></li>
 543
 544  <li><a href="http://people.skolelinux.org/pere/blog/tags/frikanalen">frikanalen (11)</a></li>
 545
 546  <li><a href="http://people.skolelinux.org/pere/blog/tags/intervju">intervju (37)</a></li>
 547
 548  <li><a href="http://people.skolelinux.org/pere/blog/tags/isenkram">isenkram (7)</a></li>
 549
 550  <li><a href="http://people.skolelinux.org/pere/blog/tags/kart">kart (18)</a></li>
 551
 552  <li><a href="http://people.skolelinux.org/pere/blog/tags/ldap">ldap (8)</a></li>
 553
 554  <li><a href="http://people.skolelinux.org/pere/blog/tags/lenker">lenker (6)</a></li>
 555
 556  <li><a href="http://people.skolelinux.org/pere/blog/tags/ltsp">ltsp (1)</a></li>
 557
 558  <li><a href="http://people.skolelinux.org/pere/blog/tags/mesh network">mesh network (2)</a></li>
 559
 560  <li><a href="http://people.skolelinux.org/pere/blog/tags/multimedia">multimedia (25)</a></li>
 561
 562  <li><a href="http://people.skolelinux.org/pere/blog/tags/norsk">norsk (236)</a></li>
 563
 564  <li><a href="http://people.skolelinux.org/pere/blog/tags/nuug">nuug (156)</a></li>
 565
 566  <li><a href="http://people.skolelinux.org/pere/blog/tags/offentlig innsyn">offentlig innsyn (8)</a></li>
 567
 568  <li><a href="http://people.skolelinux.org/pere/blog/tags/open311">open311 (2)</a></li>
 569
 570  <li><a href="http://people.skolelinux.org/pere/blog/tags/opphavsrett">opphavsrett (45)</a></li>
 571
 572  <li><a href="http://people.skolelinux.org/pere/blog/tags/personvern">personvern (67)</a></li>
 573
 574  <li><a href="http://people.skolelinux.org/pere/blog/tags/raid">raid (1)</a></li>
 575
 576  <li><a href="http://people.skolelinux.org/pere/blog/tags/reprap">reprap (11)</a></li>
 577
 578  <li><a href="http://people.skolelinux.org/pere/blog/tags/rfid">rfid (2)</a></li>
 579
 580  <li><a href="http://people.skolelinux.org/pere/blog/tags/robot">robot (8)</a></li>
 581
 582  <li><a href="http://people.skolelinux.org/pere/blog/tags/rss">rss (1)</a></li>
 583
 584  <li><a href="http://people.skolelinux.org/pere/blog/tags/ruter">ruter (4)</a></li>
 585
 586  <li><a href="http://people.skolelinux.org/pere/blog/tags/scraperwiki">scraperwiki (2)</a></li>
 587
 588  <li><a href="http://people.skolelinux.org/pere/blog/tags/sikkerhet">sikkerhet (32)</a></li>
 589
 590  <li><a href="http://people.skolelinux.org/pere/blog/tags/sitesummary">sitesummary (4)</a></li>
 591
 592  <li><a href="http://people.skolelinux.org/pere/blog/tags/skepsis">skepsis (4)</a></li>
 593
 594  <li><a href="http://people.skolelinux.org/pere/blog/tags/standard">standard (43)</a></li>
 595
 596  <li><a href="http://people.skolelinux.org/pere/blog/tags/stavekontroll">stavekontroll (3)</a></li>
 597
 598  <li><a href="http://people.skolelinux.org/pere/blog/tags/stortinget">stortinget (9)</a></li>
 599
 600  <li><a href="http://people.skolelinux.org/pere/blog/tags/surveillance">surveillance (20)</a></li>
 601
 602  <li><a href="http://people.skolelinux.org/pere/blog/tags/sysadmin">sysadmin (1)</a></li>
 603
 604  <li><a href="http://people.skolelinux.org/pere/blog/tags/valg">valg (8)</a></li>
 605
 606  <li><a href="http://people.skolelinux.org/pere/blog/tags/video">video (39)</a></li>
 607
 608  <li><a href="http://people.skolelinux.org/pere/blog/tags/vitenskap">vitenskap (4)</a></li>
 609
 610  <li><a href="http://people.skolelinux.org/pere/blog/tags/web">web (28)</a></li>
 611
 612 </ul>
 613
 614
 615     </div>
 616     <p style="text-align: right">
 617  Created by <a href="http://steve.org.uk/Software/chronicle">Chronicle v4.6</a>
 618 </p>
 619
 620   </body>
 621 </html>