summaryrefslogtreecommitdiffstats
path: root/docs/manual/mod/mod_authnz_ldap.xml
blob: a25221b56419b8604f01882e166b80c52612f1f9 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
<?xml version="1.0"?>
<!DOCTYPE modulesynopsis SYSTEM "../style/modulesynopsis.dtd">
<?xml-stylesheet type="text/xsl" href="../style/manual.en.xsl"?>
<!-- $LastChangedRevision$ -->

<!--
 Licensed to the Apache Software Foundation (ASF) under one or more
 contributor license agreements.  See the NOTICE file distributed with
 this work for additional information regarding copyright ownership.
 The ASF licenses this file to You under the Apache License, Version 2.0
 (the "License"); you may not use this file except in compliance with
 the License.  You may obtain a copy of the License at

     http://www.apache.org/licenses/LICENSE-2.0

 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
-->

<modulesynopsis metafile="mod_authnz_ldap.xml.meta">

<name>mod_authnz_ldap</name>
<description>Allows an LDAP directory to be used to store the database
for HTTP Basic authentication.</description>
<status>Extension</status>
<sourcefile>mod_authnz_ldap.c</sourcefile>
<identifier>authnz_ldap_module</identifier>

<summary>
    <p>This module allows authentication front-ends such as
    <module>mod_auth_basic</module> to authenticate users through
    an ldap directory.</p>

    <p><module>mod_authnz_ldap</module> supports the following features:</p>

    <ul>
      <li>Known to support the <a
      href="http://www.openldap.org/">OpenLDAP SDK</a> (both 1.x
      and 2.x), <a href="http://developer.novell.com/ndk/cldap.htm">
      Novell LDAP SDK</a> and the <a
      href="http://www.iplanet.com/downloads/developer/">iPlanet
      (Netscape)</a> SDK.</li>

      <li>Complex authorization policies can be implemented by
      representing the policy with LDAP filters.</li>

      <li>Uses extensive caching of LDAP operations via <a
      href="mod_ldap.html">mod_ldap</a>.</li>

      <li>Support for LDAP over SSL (requires the Netscape SDK) or
      TLS (requires the OpenLDAP 2.x SDK or Novell LDAP SDK).</li>
    </ul>

    <p>When using <module>mod_auth_basic</module>, this module is invoked
    via the <directive module="mod_auth_basic">AuthBasicProvider</directive>
    directive with the <code>ldap</code> value.</p>
</summary>

<seealso><module>mod_ldap</module></seealso>
<seealso><module>mod_auth_basic</module></seealso>
<seealso><module>mod_authz_user</module></seealso>
<seealso><module>mod_authz_groupfile</module></seealso>

<section id="contents"><title>Contents</title>

    <ul>
      <li> <a href="#gcaveats">General caveats</a> </li>
      <li> <a href="#operation">Operation</a>

        <ul>
          <li><a href="#authenphase">The Authentication
          Phase</a></li>

          <li><a href="#authorphase">The Authorization
          Phase</a></li>
        </ul>
      </li>

      <li>
        <a href="#requiredirectives">The Require Directives</a>

        <ul>
          <li><a href="#requser">Require ldap-user</a></li>
          <li><a href="#reqgroup">Require ldap-group</a></li>
          <li><a href="#reqdn">Require ldap-dn</a></li>
          <li><a href="#reqattribute">Require ldap-attribute</a></li>
          <li><a href="#reqfilter">Require ldap-filter</a></li>
          <li><a href="#reqsearch">Require ldap-search</a></li>
        </ul>
      </li>

      <li><a href="#examples">Examples</a></li>
      <li><a href="#usingtls">Using TLS</a></li>
      <li><a href="#usingssl">Using SSL</a></li>
      <li><a href="#exposed">Exposing Login Information</a></li>
      <li><a href="#activedirectory">Using Active Directory</a></li>
      <li>
        <a href="#frontpage">Using Microsoft FrontPage with
        <module>mod_authnz_ldap</module></a>

        <ul>
          <li><a href="#howitworks">How It Works</a></li>
          <li><a href="#fpcaveats">Caveats</a></li>
        </ul>
      </li>
    </ul>
</section>

<section id="gcaveats"><title>General caveats</title>
<p> This module caches authentication and authorization results based
on the configuration of <module>mod_ldap</module>. Changes
made to the backing LDAP server will not be immediately reflected on the
HTTP Server, including but not limited to user lockouts/revocations, 
password changes, or changes to group memberships.  Consult the directives 
in <module>mod_ldap</module> for details of the cache tunables.
</p>
</section>

<section id="operation"><title>Operation</title>

    <p>There are two phases in granting access to a user. The first
    phase is authentication, in which the <module>mod_authnz_ldap</module>
    authentication provider verifies that the user's credentials are valid.
    This is also called the <em>search/bind</em> phase. The second phase is
    authorization, in which <module>mod_authnz_ldap</module> determines
    if the authenticated user is allowed access to the resource in
    question. This is also known as the <em>compare</em>
    phase.</p>

    <p><module>mod_authnz_ldap</module> registers both an authn_ldap authentication
    provider and an authz_ldap authorization handler.  The authn_ldap
    authentication provider can be enabled through the
    <directive module="mod_auth_basic">AuthBasicProvider</directive> directive
    using the <code>ldap</code> value. The authz_ldap handler extends the
    <directive module="mod_authz_core">Require</directive> directive's authorization types
    by adding <code>ldap-user</code>, <code>ldap-dn</code> and <code>ldap-group</code>
    values.</p>

<section id="authenphase"><title>The Authentication
    Phase</title>

    <p>During the authentication phase, <module>mod_authnz_ldap</module>
    searches for an entry in the directory that matches the username
    that the HTTP client passes. If a single unique match is found,
    then <module>mod_authnz_ldap</module> attempts to bind to the
    directory server using the DN of the entry plus the password
    provided by the HTTP client. Because it does a search, then a
    bind, it is often referred to as the search/bind phase. Here are
    the steps taken during the search/bind phase.</p>

    <ol>
      <li>Generate a search filter by combining the attribute and
      filter provided in the <directive module="mod_authnz_ldap"
      >AuthLDAPURL</directive> directive with
      the username passed by the HTTP client.</li>

      <li>Search the directory using the generated filter. If the
      search does not return exactly one entry, deny or decline
      access.</li>

      <li>Fetch the distinguished name of the entry retrieved from
      the search and attempt to bind to the LDAP server using that
      DN and the password passed by the HTTP client. If the bind is
      unsuccessful, deny or decline access.</li>
    </ol>

    <p>The following directives are used during the search/bind
    phase</p>

    <table>
      <columnspec><column width=".3"/><column width=".7"/></columnspec>
      <tr>
        <td><directive module="mod_authnz_ldap">AuthLDAPURL</directive></td>

        <td>Specifies the LDAP server, the
        base DN, the attribute to use in the search, as well as the
        extra search filter to use.</td>
      </tr>

      <tr>
        <td><directive module="mod_authnz_ldap">AuthLDAPBindDN</directive></td>

        <td>An optional DN to bind with
        during the search phase.</td>
      </tr>

      <tr>
        <td><directive
        module="mod_authnz_ldap">AuthLDAPBindPassword</directive></td>

        <td>An optional password to bind
        with during the search phase.</td>
      </tr>
    </table>
</section>

<section id="authorphase"><title>The Authorization Phase</title>

    <p>During the authorization phase, <module>mod_authnz_ldap</module>
    attempts to determine if the user is authorized to access the
    resource.  Many of these checks require
    <module>mod_authnz_ldap</module> to do a compare operation on the
    LDAP server. This is why this phase is often referred to as the
    compare phase. <module>mod_authnz_ldap</module> accepts the
    following <directive module="mod_authz_core">Require</directive>
    directives to determine if the credentials are acceptable:</p>

    <ul>
      <li>Grant access if there is a <a
      href="#reqgroup"><code>Require ldap-user</code></a> directive, and the
      username in the directive matches the username passed by the
      client.</li>

      <li>Grant access if there is a <a href="#reqdn"><code>Require
      ldap-dn</code></a> directive, and the DN in the directive matches
      the DN fetched from the LDAP directory.</li>

      <li>Grant access if there is a <a
      href="#reqgroup"><code>Require ldap-group</code></a> directive, and
      the DN fetched from the LDAP directory (or the username
      passed by the client) occurs in the LDAP group or, potentially, in
      one of its sub-groups.</li>

      <li>Grant access if there is a <a href="#reqattribute">
      <code>Require ldap-attribute</code></a>
      directive, and the attribute fetched from the LDAP directory
      matches the given value.</li>

      <li>Grant access if there is a <a href="#reqfilter">
      <code>Require ldap-filter</code></a>
      directive, and the search filter successfully finds a single user
      object that matches the dn of the authenticated user.</li>

      <li>Grant access if there is a <a href="#reqsearch">
      <code>Require ldap-search</code></a>
      directive, and the search filter successfully returns a single
      matching object with any distinguished name.</li>

      <li>otherwise, deny or decline access</li>
    </ul>

    <p>Other <directive module="mod_authz_core">Require</directive> values may also
    be used which may require loading additional authorization modules.</p>

    <ul>
        <li>Grant access to all successfully authenticated users if
        there is a <a href="#requser"><code>Require valid-user</code></a>
        directive. (requires <module>mod_authz_user</module>)</li>

        <li>Grant access if there is a <a
        href="#reqgroup"><code>Require group</code></a> directive, and
        <module>mod_authz_groupfile</module> has been loaded with the
        <directive module="mod_authz_groupfile">AuthGroupFile</directive>
        directive set.</li>

        <li>others...</li>
     </ul>


    <p><module>mod_authnz_ldap</module> uses the following directives during the
    compare phase:</p>

    <table>
      <columnspec><column width=".4"/><column width=".6"/></columnspec>
      <tr>
        <td><directive module="mod_authnz_ldap">AuthLDAPURL</directive> </td>

        <td>The attribute specified in the
        URL is used in compare operations for the <code>Require
        ldap-user</code> operation.</td>
      </tr>

      <tr>
        <td><directive
        module="mod_authnz_ldap">AuthLDAPCompareDNOnServer</directive></td>

        <td>Determines the behavior of the
        <code>Require ldap-dn</code> directive.</td>
      </tr>

      <tr>
        <td><directive
        module="mod_authnz_ldap">AuthLDAPGroupAttribute</directive></td>

        <td>Determines the attribute to
        use for comparisons in the <code>Require ldap-group</code>
        directive.</td>
      </tr>

      <tr>
        <td><directive
        module="mod_authnz_ldap">AuthLDAPGroupAttributeIsDN</directive></td>

        <td>Specifies whether to use the
        user DN or the username when doing comparisons for the
        <code>Require ldap-group</code> directive.</td>
      </tr>

      <tr>
        <td><directive
        module="mod_authnz_ldap">AuthLDAPMaxSubGroupDepth</directive></td>

        <td>Determines the maximum depth of sub-groups that will be evaluated
        during comparisons in the <code>Require ldap-group</code> directive.</td>
      </tr>

      <tr>
        <td><directive
        module="mod_authnz_ldap">AuthLDAPSubGroupAttribute</directive></td>

        <td>Determines the attribute to use when obtaining sub-group members
        of the current group during comparisons in the <code>Require ldap-group</code>
        directive.</td>
      </tr>

      <tr>
        <td><directive
        module="mod_authnz_ldap">AuthLDAPSubGroupClass</directive></td>

        <td>Specifies the LDAP objectClass values used to identify if queried directory
        objects really are group objects (as opposed to user objects) during the
        <code>Require ldap-group</code> directive's sub-group processing.</td>
      </tr>
    </table>
</section>
</section>

<section id="requiredirectives"><title>The Require Directives</title>

    <p>Apache's <directive module="mod_authz_core">Require</directive>
    directives are used during the authorization phase to ensure that
    a user is allowed to access a resource.  mod_authnz_ldap extends the
    authorization types with <code>ldap-user</code>, <code>ldap-dn</code>,
    <code>ldap-group</code>, <code>ldap-attribute</code> and
    <code>ldap-filter</code>.  Other authorization types may also be
    used but may require that additional authorization modules be loaded.</p>

    <p>Since v2.4.8, <a href="../expr.html">expressions</a> are supported
    within the LDAP require directives.</p>

<section id="requser"><title>Require ldap-user</title>

    <p>The <code>Require ldap-user</code> directive specifies what
    usernames can access the resource. Once
    <module>mod_authnz_ldap</module> has retrieved a unique DN from the
    directory, it does an LDAP compare operation using the username
    specified in the <code>Require ldap-user</code> to see if that username
    is part of the just-fetched LDAP entry.  Multiple users can be
    granted access by putting multiple usernames on the line,
    separated with spaces. If a username has a space in it, then it
    must be surrounded with double quotes. Multiple users can also be
    granted access by using multiple <code>Require ldap-user</code>
    directives, with one user per line. For example, with a <directive
    module="mod_authnz_ldap">AuthLDAPURL</directive> of
    <code>ldap://ldap/o=Example?cn</code> (i.e., <code>cn</code> is
    used for searches), the following Require directives could be used
    to restrict access:</p>
<highlight language="config">
Require ldap-user "Barbara Jenson"
Require ldap-user "Fred User"
Require ldap-user "Joe Manager"
</highlight>

    <p>Because of the way that <module>mod_authnz_ldap</module> handles this
    directive, Barbara Jenson could sign on as <em>Barbara
    Jenson</em>, <em>Babs Jenson</em> or any other <code>cn</code> that
    she has in her LDAP entry. Only the single <code>Require
    ldap-user</code> line is needed to support all values of the attribute
    in the user's entry.</p>

    <p>If the <code>uid</code> attribute was used instead of the
    <code>cn</code> attribute in the URL above, the above three lines
    could be condensed to</p>
<highlight language="config">
Require ldap-user bjenson fuser jmanager
</highlight>
</section>

<section id="reqgroup"><title>Require ldap-group</title>

    <p>This directive specifies an LDAP group whose members are
    allowed access. It takes the distinguished name of the LDAP
    group. Note: Do not surround the group name with quotes.
    For example, assume that the following entry existed in
    the LDAP directory:</p>
<example><pre>
dn: cn=Administrators, o=Example
objectClass: groupOfUniqueNames
uniqueMember: cn=Barbara Jenson, o=Example
uniqueMember: cn=Fred User, o=Example
</pre></example>

    <p>The following directive would grant access to both Fred and
    Barbara:</p>
<highlight language="config">
Require ldap-group cn=Administrators, o=Example
</highlight>

    <p>Members can also be found within sub-groups of a specified LDAP group
    if <directive module="mod_authnz_ldap">AuthLDAPMaxSubGroupDepth</directive>
    is set to a value greater than 0. For example, assume the following entries
    exist in the LDAP directory:</p>
<example><pre>
dn: cn=Employees, o=Example
objectClass: groupOfUniqueNames
uniqueMember: cn=Managers, o=Example
uniqueMember: cn=Administrators, o=Example
uniqueMember: cn=Users, o=Example

dn: cn=Managers, o=Example
objectClass: groupOfUniqueNames
uniqueMember: cn=Bob Ellis, o=Example
uniqueMember: cn=Tom Jackson, o=Example

dn: cn=Administrators, o=Example
objectClass: groupOfUniqueNames
uniqueMember: cn=Barbara Jenson, o=Example
uniqueMember: cn=Fred User, o=Example

dn: cn=Users, o=Example
objectClass: groupOfUniqueNames
uniqueMember: cn=Allan Jefferson, o=Example
uniqueMember: cn=Paul Tilley, o=Example
uniqueMember: cn=Temporary Employees, o=Example

dn: cn=Temporary Employees, o=Example
objectClass: groupOfUniqueNames
uniqueMember: cn=Jim Swenson, o=Example
uniqueMember: cn=Elliot Rhodes, o=Example
</pre></example>

    <p>The following directives would allow access for Bob Ellis, Tom Jackson,
    Barbara Jenson, Fred User, Allan Jefferson, and Paul Tilley but would not
    allow access for Jim Swenson, or Elliot Rhodes (since they are at a
    sub-group depth of 2):</p>
<highlight language="config">
Require ldap-group cn=Employees, o=Example
AuthLDAPMaxSubGroupDepth 1
</highlight>

    <p>Behavior of this directive is modified by the <directive
    module="mod_authnz_ldap">AuthLDAPGroupAttribute</directive>, <directive
    module="mod_authnz_ldap">AuthLDAPGroupAttributeIsDN</directive>, <directive
    module="mod_authnz_ldap">AuthLDAPMaxSubGroupDepth</directive>, <directive
    module="mod_authnz_ldap">AuthLDAPSubGroupAttribute</directive>, and <directive
    module="mod_authnz_ldap">AuthLDAPSubGroupClass</directive>
    directives.</p>
</section>

<section id="reqdn"><title>Require ldap-dn</title>

    <p>The <code>Require ldap-dn</code> directive allows the administrator
    to grant access based on distinguished names. It specifies a DN
    that must match for access to be granted. If the distinguished
    name that was retrieved from the directory server matches the
    distinguished name in the <code>Require ldap-dn</code>, then
    authorization is granted. Note: do not surround the distinguished
    name with quotes.</p>

    <p>The following directive would grant access to a specific
    DN:</p>
<highlight language="config">
Require ldap-dn cn=Barbara Jenson, o=Example
</highlight>

    <p>Behavior of this directive is modified by the <directive
    module="mod_authnz_ldap">AuthLDAPCompareDNOnServer</directive>
    directive.</p>
</section>

<section id="reqattribute"><title>Require ldap-attribute</title>

    <p>The <code>Require ldap-attribute</code> directive allows the
    administrator to grant access based on attributes of the authenticated
    user in the LDAP directory.  If the attribute in the directory
    matches the value given in the configuration, access is granted.</p>

    <p>The following directive would grant access to anyone with
    the attribute employeeType = active</p>

    <highlight language="config">
Require ldap-attribute employeeType="active"
</highlight>

    <p>Multiple attribute/value pairs can be specified on the same line
    separated by spaces or they can be specified in multiple
    <code>Require ldap-attribute</code> directives. The effect of listing
    multiple attribute/values pairs is an OR operation. Access will be
    granted if any of the listed attribute values match the value of the
    corresponding attribute in the user object. If the value of the
    attribute contains a space, only the value must be within double quotes.</p>

    <p>The following directive would grant access to anyone with
    the city attribute equal to "San Jose" or status equal to "Active"</p>

    <highlight language="config">
Require ldap-attribute city="San Jose" status="active"
</highlight>

</section>

<section id="reqfilter"><title>Require ldap-filter</title>

    <p>The <code>Require ldap-filter</code> directive allows the
    administrator to grant access based on a complex LDAP search filter.
    If the dn returned by the filter search matches the authenticated user
    dn, access is granted.</p>

    <p>The following directive would grant access to anyone having a cell phone
    and is in the marketing department</p>

    <highlight language="config">
Require ldap-filter "&amp;(cell=*)(department=marketing)"
</highlight>

    <p>The difference between the <code>Require ldap-filter</code> directive and the
    <code>Require ldap-attribute</code> directive is that <code>ldap-filter</code>
    performs a search operation on the LDAP directory using the specified search
    filter rather than a simple attribute comparison. If a simple attribute
    comparison is all that is required, the comparison operation performed by
    <code>ldap-attribute</code> will be faster than the search operation
    used by <code>ldap-filter</code> especially within a large directory.</p>

    <p>When using an <a href="../expr.html">expression</a> within the filter, care
    must be taken to ensure that LDAP filters are escaped correctly to guard against
    LDAP injection. The ldap function can be used for this purpose.</p>

<highlight language="config">
&lt;LocationMatch "^/dav/(?&lt;SITENAME&gt;[^/]+)/"&gt;
  Require ldap-filter "(memberOf=cn=%{ldap:%{unescape:%{env:MATCH_SITENAME}},ou=Websites,o=Example)"
&lt;/LocationMatch&gt;
</highlight>

</section>

<section id="reqsearch"><title>Require ldap-search</title>

    <p>The <code>Require ldap-search</code> directive allows the
    administrator to grant access based on a generic LDAP search filter using an
    <a href="../expr.html">expression</a>. If there is exactly one match to the search filter,
    regardless of the distinguished name, access is granted.</p>

    <p>The following directive would grant access to URLs that match the given objects in the
    LDAP server:</p>

<highlight language="config">
&lt;LocationMatch "^/dav/(?&lt;SITENAME&gt;[^/]+)/"&gt;
Require ldap-search "(cn=%{ldap:%{unescape:%{env:MATCH_SITENAME}} Website)"
&lt;/LocationMatch&gt;
</highlight>

    <p>Note: care must be taken to ensure that any expressions are properly escaped to guard
    against LDAP injection. The <strong>ldap</strong> function can be used as per the example
    above.</p>

</section>

</section>

<section id="examples"><title>Examples</title>

    <ul>
      <li>
        Grant access to anyone who exists in the LDAP directory,
        using their UID for searches.
<highlight language="config">
AuthLDAPURL "ldap://ldap1.example.com:389/ou=People, o=Example?uid?sub?(objectClass=*)"
Require valid-user
</highlight>
      </li>

      <li>
        The next example is the same as above; but with the fields
        that have useful defaults omitted. Also, note the use of a
        redundant LDAP server.
<highlight language="config">
AuthLDAPURL "ldap://ldap1.example.com ldap2.example.com/ou=People, o=Example"
Require valid-user
</highlight>
      </li>

      <li>
        The next example is similar to the previous one, but it
        uses the common name instead of the UID. Note that this
        could be problematical if multiple people in the directory
        share the same <code>cn</code>, because a search on <code>cn</code>
        <strong>must</strong> return exactly one entry. That's why
        this approach is not recommended: it's a better idea to
        choose an attribute that is guaranteed unique in your
        directory, such as <code>uid</code>.
<highlight language="config">
AuthLDAPURL "ldap://ldap.example.com/ou=People, o=Example?cn"
Require valid-user
</highlight>
      </li>

      <li>
        Grant access to anybody in the Administrators group. The
        users must authenticate using their UID.
<highlight language="config">
AuthLDAPURL ldap://ldap.example.com/o=Example?uid
Require ldap-group cn=Administrators, o=Example
</highlight>
      </li>

      <li>
        Grant access to anybody in the group whose name matches the
        hostname of the virtual host. In this example an
        <a href="../expr.html">expression</a> is used to build the filter.
<highlight language="config">
AuthLDAPURL ldap://ldap.example.com/o=Example?uid
Require ldap-group cn=%{SERVER_NAME}, o=Example
</highlight>
      </li>

      <li>
        The next example assumes that everyone at Example who
        carries an alphanumeric pager will have an LDAP attribute
        of <code>qpagePagerID</code>. The example will grant access
        only to people (authenticated via their UID) who have
        alphanumeric pagers:
<highlight language="config">
AuthLDAPURL ldap://ldap.example.com/o=Example?uid??(qpagePagerID=*)
Require valid-user
</highlight>
      </li>

      <li>
        <p>The next example demonstrates the power of using filters
        to accomplish complicated administrative requirements.
        Without filters, it would have been necessary to create a
        new LDAP group and ensure that the group's members remain
        synchronized with the pager users. This becomes trivial
        with filters. The goal is to grant access to anyone who has
        a pager, plus grant access to Joe Manager, who doesn't
        have a pager, but does need to access the same
        resource:</p>
<highlight language="config">
AuthLDAPURL ldap://ldap.example.com/o=Example?uid??(|(qpagePagerID=*)(uid=jmanager))
Require valid-user
</highlight>

        <p>This last may look confusing at first, so it helps to
        evaluate what the search filter will look like based on who
        connects, as shown below.  If
        Fred User connects as <code>fuser</code>, the filter would look
        like</p>

        <example>(&amp;(|(qpagePagerID=*)(uid=jmanager))(uid=fuser))</example>

        <p>The above search will only succeed if <em>fuser</em> has a
        pager. When Joe Manager connects as <em>jmanager</em>, the
        filter looks like</p>

        <example>(&amp;(|(qpagePagerID=*)(uid=jmanager))(uid=jmanager))</example>

        <p>The above search will succeed whether <em>jmanager</em>
        has a pager or not.</p>
      </li>
    </ul>
</section>

<section id="usingtls"><title>Using TLS</title>

    <p>To use TLS, see the <module>mod_ldap</module> directives <directive
    module="mod_ldap">LDAPTrustedClientCert</directive>, <directive
    module="mod_ldap">LDAPTrustedGlobalCert</directive> and <directive
    module="mod_ldap">LDAPTrustedMode</directive>.</p>

    <p>An optional second parameter can be added to the
    <directive module="mod_authnz_ldap">AuthLDAPURL</directive> to override
    the default connection type set by <directive module="mod_ldap">LDAPTrustedMode</directive>.
    This will allow the connection established by an <em>ldap://</em> Url
    to be upgraded to a secure connection on the same port.</p>
</section>

<section id="usingssl"><title>Using SSL</title>

    <p>To use SSL, see the <module>mod_ldap</module> directives <directive
    module="mod_ldap">LDAPTrustedClientCert</directive>, <directive
    module="mod_ldap">LDAPTrustedGlobalCert</directive> and <directive
    module="mod_ldap">LDAPTrustedMode</directive>.</p>

    <p>To specify a secure LDAP server, use <em>ldaps://</em> in the
    <directive module="mod_authnz_ldap">AuthLDAPURL</directive>
    directive, instead of <em>ldap://</em>.</p>
</section>

<section id="exposed"><title>Exposing Login Information</title>

    <p>when this module performs <em>authentication</em>, ldap attributes specified
    in the <directive module="mod_authnz_ldap">AuthLDAPURL</directive>
    directive are placed in environment variables with the prefix "AUTHENTICATE_".</p>

    <p>when this module performs <em>authorization</em>, ldap attributes specified
    in the <directive module="mod_authnz_ldap">AuthLDAPURL</directive>
    directive are placed in environment variables with the prefix "AUTHORIZE_".</p>

    <p>If the attribute field contains the username, common name
    and telephone number of a user, a CGI program will have access to
    this information without the need to make a second independent LDAP
    query to gather this additional information.</p>

    <p>This has the potential to dramatically simplify the coding and
    configuration required in some web applications.</p>

</section>

<section id="activedirectory"><title>Using Active Directory</title>

    <p>An Active Directory installation may support multiple domains at the
    same time. To distinguish users between domains, an identifier called
    a User Principle Name (UPN) can be added to a user's entry in the
    directory. This UPN usually takes the form of the user's account
    name, followed by the domain components of the particular domain,
    for example <em>somebody@nz.example.com</em>.</p>

    <p>You may wish to configure the <module>mod_authnz_ldap</module>
    module to authenticate users present in any of the domains making up
    the Active Directory forest. In this way both
    <em>somebody@nz.example.com</em> and <em>someone@au.example.com</em>
    can be authenticated using the same query at the same time.</p>

    <p>To make this practical, Active Directory supports the concept of
    a Global Catalog. This Global Catalog is a read only copy of selected
    attributes of all the Active Directory servers within the Active
    Directory forest. Querying the Global Catalog allows all the domains
    to be queried in a single query, without the query spanning servers
    over potentially slow links.</p>

    <p>If enabled, the Global Catalog is an independent directory server
    that runs on port 3268 (3269 for SSL). To search for a user, do a
    subtree search for the attribute <em>userPrincipalName</em>, with
    an empty search root, like so:</p>

<highlight language="config">
AuthLDAPBindDN apache@example.com
AuthLDAPBindPassword password
AuthLDAPURL ldap://10.0.0.1:3268/?userPrincipalName?sub
</highlight>

    <p>Users will need to enter their User Principal Name as a login, in
    the form <em>somebody@nz.example.com</em>.</p>

</section>

<section id="frontpage"><title>Using Microsoft
    FrontPage with mod_authnz_ldap</title>

    <p>Normally, FrontPage uses FrontPage-web-specific user/group
    files (i.e., the <module>mod_authn_file</module> and
    <module>mod_authz_groupfile</module> modules) to handle all
    authentication. Unfortunately, it is not possible to just
    change to LDAP authentication by adding the proper directives,
    because it will break the <em>Permissions</em> forms in
    the FrontPage client, which attempt to modify the standard
    text-based authorization files.</p>

    <p>Once a FrontPage web has been created, adding LDAP
    authentication to it is a matter of adding the following
    directives to <em>every</em> <code>.htaccess</code> file
    that gets created in the web</p>
<highlight language="config">
AuthLDAPURL       "the url"
AuthGroupFile     "mygroupfile"
Require group     "mygroupfile"
</highlight>

<section id="howitworks"><title>How It Works</title>

    <p>FrontPage restricts access to a web by adding the <code>Require
    valid-user</code> directive to the <code>.htaccess</code>
    files. The <code>Require valid-user</code> directive will succeed for
    any user who is valid <em>as far as LDAP is
    concerned</em>. This means that anybody who has an entry in
    the LDAP directory is considered a valid user, whereas FrontPage
    considers only those people in the local user file to be
    valid. By substituting the ldap-group with group file authorization,
    Apache is allowed to consult the local user file (which is managed by
    FrontPage) - instead of LDAP - when handling authorizing the user.</p>

    <p>Once directives have been added as specified above,
    FrontPage users will be able to perform all management
    operations from the FrontPage client.</p>
</section>

<section id="fpcaveats"><title>Caveats</title>

    <ul>
      <li>When choosing the LDAP URL, the attribute to use for
      authentication should be something that will also be valid
      for putting into a <module>mod_authn_file</module> user file.
      The user ID is ideal for this.</li>

      <li>When adding users via FrontPage, FrontPage administrators
      should choose usernames that already exist in the LDAP
      directory (for obvious reasons). Also, the password that the
      administrator enters into the form is ignored, since Apache
      will actually be authenticating against the password in the
      LDAP database, and not against the password in the local user
      file. This could cause confusion for web administrators.</li>

      <!-- XXX is that true? was mod_auth before the aaa change -->
      <li>Apache must be compiled with <module>mod_auth_basic</module>,
      <module>mod_authn_file</module> and
      <module>mod_authz_groupfile</module> in order to
      use FrontPage support. This is because Apache will still use
      the <module>mod_authz_groupfile</module> group file for determine
      the extent of a user's access to the FrontPage web.</li>

      <li>The directives must be put in the <code>.htaccess</code>
      files. Attempting to put them inside <directive module="core"
      type="section">Location</directive> or <directive module="core"
      type="section">Directory</directive> directives won't work. This
      is because <module>mod_authnz_ldap</module> has to be able to grab
      the <directive module="mod_authz_groupfile">AuthGroupFile</directive>
      directive that is found in FrontPage <code>.htaccess</code>
      files so that it knows where to look for the valid user list. If
      the <module>mod_authnz_ldap</module> directives aren't in the same
      <code>.htaccess</code> file as the FrontPage directives, then
      the hack won't work, because <module>mod_authnz_ldap</module> will
      never get a chance to process the <code>.htaccess</code> file,
      and won't be able to find the FrontPage-managed user file.</li>
    </ul>
</section>
</section>

<directivesynopsis>
<name>AuthLDAPAuthorizePrefix</name>
<description>Specifies the prefix for environment variables set during
authorization</description>
<syntax>AuthLDAPAuthorizePrefix <em>prefix</em></syntax>
<default>AuthLDAPAuthorizePrefix AUTHORIZE_</default>
<contextlist><context>directory</context><context>.htaccess</context>
</contextlist>
<override>AuthConfig</override>
<compatibility>Available in version 2.3.6 and later</compatibility>
<usage>
    <p>This directive allows you to override the prefix used for environment
    variables set during LDAP authorization.  If <em>AUTHENTICATE_</em> is
    specified, consumers of these environment variables see the same information
    whether LDAP has performed authentication, authorization, or both.</p>

    <note><title>Note</title>
    No authorization variables are set when a user is authorized on the basis of
    <code>Require valid-user</code>.
    </note>
</usage>
</directivesynopsis>


<directivesynopsis>
<name>AuthLDAPBindAuthoritative</name>
<description>Determines if other authentication providers are used when a user can be mapped to a DN but the server cannot successfully bind with the user's credentials.</description>
<syntax>AuthLDAPBindAuthoritative off|on</syntax>
<default>AuthLDAPBindAuthoritative on</default>
<contextlist><context>directory</context><context>.htaccess</context>
</contextlist>
<override>AuthConfig</override>
<usage>
    <p>By default, subsequent authentication providers are only queried if a
    user cannot be mapped to a DN, but not if the user can be mapped to a DN and their
    password cannot be verified with an LDAP bind.
    If <directive>AuthLDAPBindAuthoritative</directive>
    is set to <em>off</em>, other configured authentication modules will have
    a chance to validate the user if the LDAP bind (with the current user's credentials)
    fails for any reason.</p>
    <p> This allows users present in both LDAP and
    <directive module="mod_authn_file">AuthUserFile</directive> to authenticate
    when the LDAP server is available but the user's account is locked or password
    is otherwise unusable.</p>
</usage>
<seealso><directive module="mod_authn_file">AuthUserFile</directive></seealso>
<seealso><directive module="mod_auth_basic">AuthBasicProvider</directive></seealso>
</directivesynopsis>

<directivesynopsis>
<name>AuthLDAPInitialBindAsUser</name>
<description>Determines if the server does the initial DN lookup using the basic authentication users'
own username, instead of anonymously or with hard-coded credentials for the server</description>
<syntax>AuthLDAPInitialBindAsUser off|on</syntax>
<default>AuthLDAPInitialBindAsUser off</default>
<contextlist><context>directory</context><context>.htaccess</context>
</contextlist>
<override>AuthConfig</override>
<compatibility>Available in version 2.3.6 and later</compatibility>
<usage>
    <p>By default, the server either anonymously, or with a dedicated user and
     password, converts the basic authentication username into an LDAP
     distinguished name (DN).  This directive forces the server to use the verbatim username
     and password provided by the incoming user to perform the initial DN
     search.</p>

     <p> If the verbatim username can't directly bind, but needs some
     cosmetic transformation, see <directive module="mod_authnz_ldap">
     AuthLDAPInitialBindPattern</directive>.</p>

     <p> This directive should only be used when your LDAP server doesn't
         accept anonymous searches and you cannot use a dedicated
         <directive module="mod_authnz_ldap">AuthLDAPBindDN</directive>.
     </p>

     <note><title>Not available with authorization-only</title>
         This directive can only be used if this module authenticates the user, and
         has no effect when this module is used exclusively for authorization.
     </note>
</usage>
<seealso><directive module="mod_authnz_ldap">AuthLDAPInitialBindPattern</directive></seealso>
<seealso><directive module="mod_authnz_ldap">AuthLDAPBindDN</directive></seealso>
<seealso><directive module="mod_authnz_ldap">AuthLDAPCompareAsUser</directive></seealso>
<seealso><directive module="mod_authnz_ldap">AuthLDAPSearchAsUser</directive></seealso>
</directivesynopsis>

<directivesynopsis>
<name>AuthLDAPInitialBindPattern</name>
<description>Specifies the transformation of the basic authentication username to be used when binding to the LDAP server
to perform a DN lookup</description>
<syntax>AuthLDAPInitialBindPattern <em><var>regex</var> <var>substitution</var></em></syntax>
<default>AuthLDAPInitialBindPattern (.*) $1 (remote username used verbatim)</default>
<contextlist><context>directory</context><context>.htaccess</context>
</contextlist>
<override>AuthConfig</override>
<compatibility>Available in version 2.3.6 and later</compatibility>
<usage>
    <p>If <directive module="mod_authnz_ldap">AuthLDAPInitialBindAsUser</directive> is set to
       <em>ON</em>, the basic authentication username will be transformed according to the
       regular expression and substitution arguments.</p>

    <p> The regular expression argument is compared against the current basic authentication username.
        The substitution argument may contain backreferences, but has no other variable interpolation.</p>

    <p> This directive should only be used when your LDAP server doesn't
        accept anonymous searches and you cannot use a dedicated
        <directive module="mod_authnz_ldap">AuthLDAPBindDN</directive>.
    </p>

    <highlight language="config">
AuthLDAPInitialBindPattern (.+) $1@example.com
    </highlight>
    <highlight language="config">
AuthLDAPInitialBindPattern (.+) cn=$1,dc=example,dc=com
    </highlight>

    <note><title>Not available with authorization-only</title>
        This directive can only be used if this module authenticates the user, and
        has no effect when this module is used exclusively for authorization.
    </note>
    <note><title>debugging</title>
        The substituted DN is recorded in the environment variable
        <em>LDAP_BINDASUSER</em>.  If the regular expression does not match the input,
        the verbatim username is used.
    </note>
</usage>
<seealso><directive module="mod_authnz_ldap">AuthLDAPInitialBindAsUser</directive></seealso>
<seealso><directive module="mod_authnz_ldap">AuthLDAPBindDN</directive></seealso>
</directivesynopsis>

<directivesynopsis>
<name>AuthLDAPBindDN</name>
<description>Optional DN to use in binding to the LDAP server</description>
<syntax>AuthLDAPBindDN <em>distinguished-name</em></syntax>
<contextlist><context>directory</context><context>.htaccess</context>
</contextlist>
<override>AuthConfig</override>

<usage>
    <p>An optional DN used to bind to the server when searching for
    entries. If not provided, <module>mod_authnz_ldap</module> will use
    an anonymous bind.</p>
</usage>
</directivesynopsis>

<directivesynopsis>
<name>AuthLDAPBindPassword</name>
<description>Password used in conjunction with the bind DN</description>
<syntax>AuthLDAPBindPassword <em>password</em></syntax>
<contextlist><context>directory</context><context>.htaccess</context>
</contextlist>
<override>AuthConfig</override>
<compatibility><em>exec:</em> was added in 2.4.5.</compatibility>

<usage>
    <p>A bind password to use in conjunction with the bind DN. Note
    that the bind password is probably sensitive data, and should be
    properly protected. You should only use the <directive
    module="mod_authnz_ldap">AuthLDAPBindDN</directive> and <directive
    >AuthLDAPBindPassword</directive> if you
    absolutely need them to search the directory.</p>

    <p>If the value begins with exec: the resulting command will be
    executed and the first line returned to standard output by the
    program will be used as the password.</p>
<highlight language="config">
#Password used as-is
AuthLDAPBindPassword secret

#Run /path/to/program to get my password
AuthLDAPBindPassword exec:/path/to/program

#Run /path/to/otherProgram and provide arguments
AuthLDAPBindPassword "exec:/path/to/otherProgram argument1"
</highlight>

</usage>
</directivesynopsis>

<directivesynopsis>
<name>AuthLDAPCharsetConfig</name>
<description>Language to charset conversion configuration file</description>
<syntax>AuthLDAPCharsetConfig <em>file-path</em></syntax>
<contextlist><context>server config</context>
</contextlist>

<usage>
    <p>The <directive>AuthLDAPCharsetConfig</directive> directive sets the location
    of the language to charset conversion configuration file. <var>File-path</var> is relative
    to the <directive module="core">ServerRoot</directive>. This file specifies
    the list of language extensions to character sets.
    Most administrators use the provided <code>charset.conv</code>
    file, which associates common language extensions to character sets.</p>

    <p>The file contains lines in the following format:</p>

    <example>
      <var>Language-Extension</var> <var>charset</var> [<var>Language-String</var>] ...
    </example>

    <p>The case of the extension does not matter. Blank lines, and lines
    beginning with a hash character (<code>#</code>) are ignored.</p>
</usage>
</directivesynopsis>

<directivesynopsis>
<name>AuthLDAPCompareAsUser</name>
<description>Use the authenticated user's credentials to perform authorization comparisons</description>
<syntax>AuthLDAPCompareAsUser on|off</syntax>
<default>AuthLDAPCompareAsUser off</default>
<contextlist><context>directory</context><context>.htaccess</context>
</contextlist>
<override>AuthConfig</override>
<compatibility>Available in version 2.3.6 and later</compatibility>

<usage>
    <p>When set, and <module>mod_authnz_ldap</module> has authenticated the
    user, LDAP comparisons for authorization use the queried distinguished name (DN)
    and HTTP basic authentication password of the authenticated user instead of
    the servers configured credentials.</p>

    <p> The <em>ldap-attribute</em>, <em>ldap-user</em>, and <em>ldap-group</em> (single-level only)
    authorization checks use comparisons.</p>

    <p>This directive only has effect on the comparisons performed during
    nested group processing when <directive module="mod_authnz_ldap">
    AuthLDAPSearchAsUser</directive> is also enabled.</p>

    <p> This directive should only be used when your LDAP server doesn't
        accept anonymous comparisons and you cannot use a dedicated
        <directive module="mod_authnz_ldap">AuthLDAPBindDN</directive>.
    </p>
</usage>
<seealso><directive module="mod_authnz_ldap">AuthLDAPInitialBindAsUser</directive></seealso>
<seealso><directive module="mod_authnz_ldap">AuthLDAPSearchAsUser</directive></seealso>
</directivesynopsis>

<directivesynopsis>
<name>AuthLDAPCompareDNOnServer</name>
<description>Use the LDAP server to compare the DNs</description>
<syntax>AuthLDAPCompareDNOnServer on|off</syntax>
<default>AuthLDAPCompareDNOnServer on</default>
<contextlist><context>directory</context><context>.htaccess</context>
</contextlist>
<override>AuthConfig</override>

<usage>
    <p>When set, <module>mod_authnz_ldap</module> will use the LDAP
    server to compare the DNs. This is the only foolproof way to
    compare DNs.  <module>mod_authnz_ldap</module> will search the
    directory for the DN specified with the <a
    href="#reqdn"><code>Require dn</code></a> directive, then,
    retrieve the DN and compare it with the DN retrieved from the user
    entry. If this directive is not set,
    <module>mod_authnz_ldap</module> simply does a string comparison. It
    is possible to get false negatives with this approach, but it is
    much faster. Note the <module>mod_ldap</module> cache can speed up
    DN comparison in most situations.</p>
</usage>
</directivesynopsis>

<directivesynopsis>
<name>AuthLDAPDereferenceAliases</name>
<description>When will the module de-reference aliases</description>
<syntax>AuthLDAPDereferenceAliases never|searching|finding|always</syntax>
<default>AuthLDAPDereferenceAliases always</default>
<contextlist><context>directory</context><context>.htaccess</context>
</contextlist>
<override>AuthConfig</override>

<usage>
    <p>This directive specifies when <module>mod_authnz_ldap</module> will
    de-reference aliases during LDAP operations. The default is
    <code>always</code>.</p>
</usage>
</directivesynopsis>

<directivesynopsis>
<name>AuthLDAPGroupAttribute</name>
<description>LDAP attributes used to identify the user members of
groups.</description>
<syntax>AuthLDAPGroupAttribute <em>attribute</em></syntax>
<default>AuthLDAPGroupAttribute member uniqueMember</default>
<contextlist><context>directory</context><context>.htaccess</context>
</contextlist>
<override>AuthConfig</override>

<usage>
    <p>This directive specifies which LDAP attributes are used to
    check for user members within groups. Multiple attributes can be used
    by specifying this directive multiple times. If not specified,
    then <module>mod_authnz_ldap</module> uses the <code>member</code> and
    <code>uniqueMember</code> attributes.</p>
</usage>
</directivesynopsis>

<directivesynopsis>
<name>AuthLDAPGroupAttributeIsDN</name>
<description>Use the DN of the client username when checking for
group membership</description>
<syntax>AuthLDAPGroupAttributeIsDN on|off</syntax>
<default>AuthLDAPGroupAttributeIsDN on</default>
<contextlist><context>directory</context><context>.htaccess</context>
</contextlist>
<override>AuthConfig</override>

<usage>
    <p>When set <code>on</code>, this directive says to use the
    distinguished name of the client username when checking for group
    membership.  Otherwise, the username will be used. For example,
    assume that the client sent the username <code>bjenson</code>,
    which corresponds to the LDAP DN <code>cn=Babs Jenson,
    o=Example</code>. If this directive is set,
    <module>mod_authnz_ldap</module> will check if the group has
    <code>cn=Babs Jenson, o=Example</code> as a member. If this
    directive is not set, then <module>mod_authnz_ldap</module> will
    check if the group has <code>bjenson</code> as a member.</p>
</usage>
</directivesynopsis>

<directivesynopsis>
<name>AuthLDAPMaxSubGroupDepth</name>
<description>Specifies the maximum sub-group nesting depth that will be
evaluated before the user search is discontinued.</description>
<syntax>AuthLDAPMaxSubGroupDepth <var>Number</var></syntax>
<default>AuthLDAPMaxSubGroupDepth 0</default>
<contextlist><context>directory</context><context>.htaccess</context>
</contextlist>
<override>AuthConfig</override>
<compatibility>Available in version 2.3.0 and later, defaulted to 10 in 2.4.x and early 2.5</compatibility>

<usage>
   <p>When this directive is set to a non-zero value <code>X</code>
   combined with use of the <code>Require ldap-group someGroupDN</code>
   directive, the provided user credentials will be searched for
   as a member of the <code>someGroupDN</code> directory object or of
   any group member of the current group up to the maximum nesting
   level <code>X</code> specified by this directive.</p>
   <p>See the <a href="#reqgroup"><code>Require ldap-group</code></a>
   section for a more detailed example.</p>

   <note><title>Nested groups performance</title>
   <p> When <directive>AuthLDAPSubGroupAttribute</directive> overlaps with
   <directive>AuthLDAPGroupAttribute</directive> (as it does by default and
   as required by common LDAP schemas), uncached searching for subgroups in
   large groups can be very slow. If you use large, non-nested groups, keep
   <directive>AuthLDAPMaxSubGroupDepth</directive> set to zero.</p>
   </note>

</usage>
</directivesynopsis>

<directivesynopsis>
<name>AuthLDAPRemoteUserAttribute</name>
<description>Use the value of the attribute returned during the user
query to set the REMOTE_USER environment variable</description>
<syntax>AuthLDAPRemoteUserAttribute uid</syntax>
<default>none</default>
<contextlist><context>directory</context><context>.htaccess</context>
</contextlist>
<override>AuthConfig</override>

<usage>
    <p>If this directive is set, the value of the
    <code>REMOTE_USER</code> environment variable will be set to the
    value of the attribute specified. Make sure that this attribute is
    included in the list of attributes in the <directive module="mod_authnz_ldap"
    >AuthLDAPURL</directive> definition,
    otherwise this directive will have no effect. This directive, if
    present, takes precedence over <directive module="mod_authnz_ldap"
    >AuthLDAPRemoteUserIsDN</directive>. This
    directive is useful should you want people to log into a website
    using an email address, but a backend application expects the
    username as a userid.</p>
    <p> This directive only has effect when this module is used for
    authentication.</p>
</usage>
</directivesynopsis>

<directivesynopsis>
<name>AuthLDAPRemoteUserIsDN</name>
<description>Use the DN of the client username to set the REMOTE_USER
environment variable</description>
<syntax>AuthLDAPRemoteUserIsDN on|off</syntax>
<default>AuthLDAPRemoteUserIsDN off</default>
<contextlist><context>directory</context><context>.htaccess</context>
</contextlist>
<override>AuthConfig</override>

<usage>
    <p>If this directive is set to on, the value of the
    <code>REMOTE_USER</code> environment variable will be set to the full
    distinguished name of the authenticated user, rather than just
    the username that was passed by the client. It is turned off by
    default.</p>
    <p> This directive only has effect when this module is used for
    authentication.</p>
</usage>
</directivesynopsis>

<directivesynopsis>
<name>AuthLDAPSearchAsUser</name>
<description>Use the authenticated user's credentials to perform authorization searches</description>
<syntax>AuthLDAPSearchAsUser on|off</syntax>
<default>AuthLDAPSearchAsUser off</default>
<contextlist><context>directory</context><context>.htaccess</context>
</contextlist>
<override>AuthConfig</override>
<compatibility>Available in version 2.3.6 and later</compatibility>

<usage>
    <p>When set, and <module>mod_authnz_ldap</module> has authenticated the
    user, LDAP searches for authorization use the queried distinguished name (DN)
    and HTTP basic authentication password of the authenticated user instead of
    the servers configured credentials.</p>

    <p> The <em>ldap-filter</em> and <em>ldap-dn</em> authorization
    checks use searches.</p>

    <p>This directive only has effect on the comparisons performed during
    nested group processing when <directive module="mod_authnz_ldap">
    AuthLDAPCompareAsUser</directive> is also enabled.</p>

    <p> This directive should only be used when your LDAP server doesn't
        accept anonymous searches and you cannot use a dedicated
        <directive module="mod_authnz_ldap">AuthLDAPBindDN</directive>.
    </p>
</usage>
<seealso><directive module="mod_authnz_ldap">AuthLDAPInitialBindAsUser</directive></seealso>
<seealso><directive module="mod_authnz_ldap">AuthLDAPCompareAsUser</directive></seealso>
</directivesynopsis>

<directivesynopsis>
<name>AuthLDAPSubGroupAttribute</name>
<description>Specifies the attribute labels, one value per
directive line, used to distinguish the members of the current group that
are groups.</description>
<syntax>AuthLDAPSubGroupAttribute <em>attribute</em></syntax>
<default>AuthLDAPSubGroupAttribute member uniqueMember</default>
<contextlist><context>directory</context><context>.htaccess</context>
</contextlist>
<override>AuthConfig</override>
<compatibility>Available in version 2.3.0 and later</compatibility>

<usage>
    <p>An LDAP group object may contain members that are users and
    members that are groups (called nested or sub groups). The
    <directive>AuthLDAPSubGroupAttribute</directive> directive identifies the
    labels of group members and the <directive module="mod_authnz_ldap"
    >AuthLDAPGroupAttribute</directive>
    directive identifies the labels of the user members. Multiple
    attributes can be used by specifying this directive multiple times.
    If not specified, then <module>mod_authnz_ldap</module> uses the
    <code>member</code> and <code>uniqueMember</code> attributes.</p>
</usage>
</directivesynopsis>

<directivesynopsis>
<name>AuthLDAPSubGroupClass</name>
<description>Specifies which LDAP objectClass values identify directory
objects that are groups during sub-group processing.</description>
<syntax>AuthLDAPSubGroupClass <em>LdapObjectClass</em></syntax>
<default>AuthLDAPSubGroupClass groupOfNames groupOfUniqueNames</default>
<contextlist><context>directory</context><context>.htaccess</context>
</contextlist>
<override>AuthConfig</override>
<compatibility>Available in version 2.3.0 and later</compatibility>

<usage>
    <p>An LDAP group object may contain members that are users and
    members that are groups (called nested or sub groups). The
    <directive module="mod_authnz_ldap">AuthLDAPSubGroupAttribute</directive>
    directive identifies the
    labels of members that may be sub-groups of the current group
    (as opposed to user members). The <directive>AuthLDAPSubGroupClass</directive>
    directive specifies the LDAP objectClass values used in verifying that
    these potential sub-groups are in fact group objects. Verified sub-groups
    can then be searched for more user or sub-group members. Multiple
    attributes can be used by specifying this directive multiple times.
    If not specified, then <module>mod_authnz_ldap</module> uses the
    <code>groupOfNames</code> and <code>groupOfUniqueNames</code> values.</p>
</usage>
</directivesynopsis>

<directivesynopsis>
<name>AuthLDAPURL</name>
<description>URL specifying the LDAP search parameters</description>
<syntax>AuthLDAPURL <em>url</em> [NONE|SSL|TLS|STARTTLS]</syntax>
<contextlist><context>directory</context><context>.htaccess</context>
</contextlist>
<override>AuthConfig</override>

<usage>
    <p>An RFC 2255 URL which specifies the LDAP search parameters
    to use. The syntax of the URL is</p>
<example>ldap://host:port/basedn?attribute?scope?filter</example>
    <p>If you want to specify more than one LDAP URL that Apache should try in turn, the syntax is:</p>
<highlight language="config">
AuthLDAPURL "ldap://ldap1.example.com ldap2.example.com/dc=..."
</highlight>
<p><em><strong>Caveat: </strong>If you specify multiple servers, you need to enclose the entire URL string in quotes;
otherwise you will get an error: "AuthLDAPURL takes one argument, URL to define LDAP connection.." </em>
You can of course use search parameters on each of these.</p>

<dl>
<dt>ldap</dt>

        <dd>For regular ldap, use the
        string <code>ldap</code>. For secure LDAP, use <code>ldaps</code>
        instead. Secure LDAP is only available if Apache was linked
        to an LDAP library with SSL support.</dd>

<dt>host:port</dt>

        <dd>
          <p>The name/port of the ldap server (defaults to
          <code>localhost:389</code> for <code>ldap</code>, and
          <code>localhost:636</code> for <code>ldaps</code>). To
          specify multiple, redundant LDAP servers, just list all
          servers, separated by spaces. <module>mod_authnz_ldap</module>
          will try connecting to each server in turn, until it makes a
          successful connection. If multiple ldap servers are specified,
          then entire LDAP URL must be encapsulated in double quotes.</p>

          <p>Once a connection has been made to a server, that
          connection remains active for the life of the
          <program>httpd</program> process, or until the LDAP server goes
          down.</p>

          <p>If the LDAP server goes down and breaks an existing
          connection, <module>mod_authnz_ldap</module> will attempt to
          re-connect, starting with the primary server, and trying
          each redundant server in turn. Note that this is different
          than a true round-robin search.</p>
        </dd>

<dt>basedn</dt>

        <dd>The DN of the branch of the
        directory where all searches should start from. At the very
        least, this must be the top of your directory tree, but
        could also specify a subtree in the directory.</dd>

<dt>attribute</dt>

        <dd>The attribute to search for.
        Although RFC 2255 allows a comma-separated list of
        attributes, only the first attribute will be used, no
        matter how many are provided. If no attributes are
        provided, the default is to use <code>uid</code>. It's a good
        idea to choose an attribute that will be unique across all
        entries in the subtree you will be using.  All attributes
        listed will be put into the environment with an AUTHENTICATE_ prefix
        for use by other modules.</dd>

<dt>scope</dt>

        <dd>The scope of the search. Can be either <code>one</code> or
        <code>sub</code>. Note that a scope of <code>base</code> is
        also supported by RFC 2255, but is not supported by this
        module. If the scope is not provided, or if <code>base</code> scope
        is specified, the default is to use a scope of
        <code>sub</code>.</dd>

<dt>filter</dt>

        <dd>A valid LDAP search filter. If
        not provided, defaults to <code>(objectClass=*)</code>, which
        will search for all objects in the tree. Filters are
        limited to approximately 8000 characters (the definition of
        <code>MAX_STRING_LEN</code> in the Apache source code). This
        should be more than sufficient for any application. In 2.4.10 and later,
        the keyword <code>none</code> disables the use of a filter; this is
        required by some primitive LDAP servers.</dd>
</dl>

    <p>When doing searches, the attribute, filter and username passed
    by the HTTP client are combined to create a search filter that
    looks like
    <code>(&amp;(<em>filter</em>)(<em>attribute</em>=<em>username</em>))</code>.</p>

    <p>For example, consider an URL of
    <code>ldap://ldap.example.com/o=Example?cn?sub?(posixid=*)</code>. When
    a client attempts to connect using a username of <code>Babs
    Jenson</code>, the resulting search filter will be
    <code>(&amp;(posixid=*)(cn=Babs Jenson))</code>.</p>

    <p>An optional parameter can be added to allow the LDAP Url to override
    the connection type.  This parameter can be one of the following:</p>

<dl>
    <dt>NONE</dt>
        <dd>Establish an unsecure connection on the default LDAP port. This
        is the same as <code>ldap://</code> on port 389.</dd>
    <dt>SSL</dt>
        <dd>Establish a secure connection on the default secure LDAP port.
        This is the same as <code>ldaps://</code></dd>
    <dt>TLS | STARTTLS</dt>
        <dd>Establish an upgraded secure connection on the default LDAP port.
        This connection will be initiated on port 389 by default and then
        upgraded to a secure connection on the same port.</dd>
</dl>

    <p>See above for examples of <directive
    module="mod_authnz_ldap">AuthLDAPURL</directive> URLs.</p>
</usage>
</directivesynopsis>

</modulesynopsis>