1Net::LDAP::FAQ(3) User Contributed Perl Documentation Net::LDAP::FAQ(3)
2
6 Net::LDAP::FAQ - Frequently Asked Questions about Net::LDAP
7
9 perldoc Net::LDAP::FAQ
10
12 This document serves to answer the most frequently asked questions on
13 both the perl-ldap Mailing List and those sent to Graham Barr.
14 The latest version of this FAQ can be found at
16 http://ldap.perl.org/FAQ.html
18
20 What is perl-ldap ?
21 perl-ldap is the distribution name. The perl-ldap distribution contains
23 the Net::LDAP modules.
24 Why another perl LDAP implementation ?
26 perl-ldap's goal is to be as portable as possible. It does this by
28 being implemented completely in perl. So basically anywhere that perl
29 runs perl-ldap will run. This is not true for other implementations
30 which require a C compiler.
31 Where can I get it ?
33 Perl-ldap is available from CPAN. You will find it in the
35 authors/id/GBARR directory. Alternatively you can download the latest
36 version from
37 http://www.cpan.org/search?dist=perl-ldap
39 WARNING: The perl-ldap module is stored on CPAN as a *.gz file. Net‐
41 scape on Windows systems sometimes has a problem storing the module
42 with the correct name, it will replace the *.tar.gz with *_tar.tar. To
43 correct the problem, with the pointer on the link, do a right click and
44 then select save link as to save the file with the correct file name.
45 Is there a web page for perl-ldap ?
47 Yes there is at http://ldap.perl.org/
49 Is there a mailing list ?
51 Yes there is at perl-ldap@perl.org
53 You can subscribe to this list by mailing perl-ldap-subscribe@perl.org
55 Is the mailing list archived ?
57 Yes, at http://nntp.perl.org/group/perl.ldap
59 Archives with messages before we switched to using perl.org can be
61 found at
62 http://marc.theaimsgroup.com/?l=perl-ldap-dev
64 There is also an archive of the perl-ldap mailing list at
66 http://www.xray.mpe.mpg.de/mailing-lists/perl-ldap/
68 which also has messages from before the move.
70 Is there any online documentation ?
72 Yes. perl-ldap has online documentation at
74 http://ldap.perl.org/
76 which will have the latest documentation available.
78 Is there a public CVS repository ?
80 No, but there is a public SVN repository at
82 http://svn.mutatus.co.uk
84 Can I get perl-ldap from the public SVN repository?
86 Yes, any one can pull perl-ldap from the public SVN repository on
88 perl.ldap.org.
89 There are several ways this can be done.
91 Web You can download it from CPAN by following the release link:
93 The 2 lines in the following example should be put together as one
95 continuous line. Example;
96 http://search.cpan.org/CPAN/authors/id/G/GB/GBARR/perl-ldap-0.33.tar.gz
98 WARNING: The perl-ldap module is stored on CPAN as a *.gz file.
100 Netscape on Windows systems sometimes has a problem storing the
101 module with the correct name, it will replace the *.tar.gz with
102 *_tar.tar. To correct the problem, with the pointer on the link,
103 do a right click and then select save link as to save the file with
104 the correct file name.
105 SVN You can download latest development version of perl-ldap from
107 svn.mutatus.co.uk by executing a anonymous SVN "checkout" command.
108 The 2 lines in the following example should be put together as one
110 continuous line. Example;
111 svn co http://svn.mutatus.co.uk/repos/perl-ldap/trunk
113 Web page
115 Most of the time there is a URL link on the perl-ldap home page on
116 ldap.perl.org that points to the latest released version of
117 perl-ldap. Due to the fact that humans must update the web page to
118 point to a new release it sometimes does not get updated as quickly
119 as it should.
120 WARNING: The perl-ldap module is stored on CPAN as a *.gz file.
122 Netscape on Windows systems sometimes has a problem storing the
123 module with the correct name, it will replace the *.tar.gz with
124 *_tar.tar. To correct the problem, with the pointer on the link,
125 do a right click and then select save link as to save the file with
126 the correct file name.
127 What is SVN.
129 "SVN" is an abbreviation for "Subversion" (see http://subver‐
131 sion.tigris.org). Subversion is a "Source Control" or "Revision Con‐
132 trol" tool designed to keep track of source changes made by groups of
133 developers working on the same files, allowing them to stay in sync
134 with each other as each individual chooses.
135
137 In order to help the user understand the perl-ldap module better some
138 key LDAP terminology is defined here.
139 What is a directory.
141 A directory is a special purpose hierarchical database that usually
143 contains typed information such as text strings, binary data, or X.509
144 certificates.
145 What is LDAP.
147 LDAP stands for Lightweight Directory Access Protocol. The word Proto‐
149 col is the key word in the definition given in the preceding sentence,
150 LDAP is NOT hardware or software. It is a protocol that defines how a
151 client and server will communicate with one another.
152 The Lightweight Directory Access Protocol is defined in a series of
154 Requests For Comments, better known as RFCs. The RFCs can be found on
155 the Internet at http://www.ietf.org/ (the master repository) and many
156 other places. There's a link to all the LDAP-related RFCs at
157 Perl-LDAP's web site, http://ldap.perl.org/rfc.html. Some of the more
158 important RFC numbers are RFC 451i0 - 4519 for LDAP (previously called
159 LDAPv3) and the historic RFC 1777 for LDAPv2.
160 What is a LDAP Directory.
162 In the strictest terms of the definition there is no such thing as a
164 LDAP directory. To be practical about this situation every day direc‐
165 tory professionals refer to their directory as " a LDAP directory"
166 because it is easy to say and it does convey the type of protocol used
167 to communicate with their directory. Using this definition a LDAP
168 directory is a directory whose server software conforms to the Light‐
169 weight Directory Access Protocol when communicating with a client.
170 What is an Entry.
172 The traditional directory definition of a directory object is called an
174 Entry. Entries are composed of attributes that contain the information
175 to be recorded about the object.
176 (An entry in LDAP is somewhat analogous to a record in a table in an
178 SQL database, but don't get too hung up about this analogy!)
179 Entries are held in an upside-down tree structure. Entries can there‐
181 fore contain subordinate entries, and entries must have one direct
182 superior entry.
183 Entries with subordinate entries are called 'non-leaf' entries.
185 Entries without subordinate entries are called 'leaf' entries.
187 An entry's direct superior entry is called the entry's 'parent'.
189 'Non-leaf' entries are also said to have 'child' entries.
191 What is an attribute.
193 The entry(s) in a directory are composed of attributes that contain
195 information about the object. Each attribute has a type and can con‐
196 tain one or more values.
197 For example:
199 cn=Road Runner
201 is an attribute with a type named "cn", and one value.
203 Each attribute is described by a 'syntax' which defines what kind of
205 information can be stored in the attributes values. Trying to store a
206 value that doesn't conform to the attribute's syntax will result in an
207 error.
208 For example:
210 jpegPhoto=unknown
212 is not permitted by the directory, because jpegPhotos may only contain
214 JPEG-formatted images.
215 Most syntaxes used in LDAP however describe text strings rather than
217 binary objects (like JPEGs or certificates.)
218 In LDAPv3 most of these syntaxes support Unicode encoded using UTF-8.
220 Because the Net::LDAP modules do not change the strings that you pass
221 in as attribute values (they get sent to the LDAP server as-is) to use
222 accented characters you simply need to encode your strings in UTF-8.
223 There are modules on CPAN that will help you here.
224 Note that LDAPv2 servers used something called T.61 instead of Unicode
226 and UTF-8. Most servers do not implement T.61 correctly, and it is rec‐
227 ommended that you use LDAPv3 instead.
228 Attributes may also be searched. The algorithms used to perform dif‐
230 ferent kinds of searches are described by the attribute's 'matching
231 rules'. Some matching rules are case-sensitive and some are
232 case-insensitive, for example. Sometimes matching rules aren't defined
233 for a particular attribute: there's no way to search for jpegPhotos
234 that contain a substring!
235 You can examine all of a server's attribute definitions by reading the
237 schema from the server.
238 What is an object class.
240 An object class is the name associated with a group of attributes that
242 must be present in an entry, and the group of attributes that may also
243 be present in an entry.
244 Object classes may be derived (subclassed) from other object classes.
246 For example the widely used 'inetOrgPerson' object class is derived
247 from 'organizationalPerson', which is itself derived from 'person'
248 which is itself derived from 'top'.
249 Every entry has an attribute called 'objectClass' that lists all the
251 names of object classes (and their superclasses) being used with the
252 entry.
253 You can examine all of a server's objectclass definitions by reading
255 the schema from the server.
256 What is a Distinguished Name (DN).
258 Every entry in a directory has a Distinguished Name, or DN. It is a
260 unique Entry identifier throughout the complete directory. No two
261 Entries can have the same DN within the same directory.
262 Examples of DNs:
264 cn=Road Runner, ou=bird, dc=cartoon, dc=com
266 ou=bird, dc=cartoon, dc=com
267 dc=cartoon, dc=com
268 dc=com
269 What is a Relative Distinguished Name.
271 Every DN is made up of a sequence of Relative Distinguished Names, or
273 RDNs. The sequences of RDNs are separated by commas (,). In LDAPv2
274 semi-colons (;) were also allowed. There can be more than one identi‐
275 cal RDN in a directory, but they must have different parent entries.
276 Technically, an RDN contains attribute-value assertions, or AVAs. When
278 an AVA is written down, the attribute name is separated from the
279 attribute value with an equals (=) sign.
280 Example of a DN:
282 cn=Road Runner,ou=bird,dc=cartoon,dc=com
284 RDNs of the proceeding DN:
286 RDN => cn=Road Runner
287 RDN => ou=bird
288 RDN => dc=cartoon
289 RDN => dc=com
290 RDNs can contain multiple attributes, though this is somewhat ususual.
292 They are called multi-AVA RDNs, and each AVA is separated in the RDN
293 from the others with a plus sign (+).
294 Example of a DN with a multi-AVA RDN:
296 cn=Road Runner+l=Arizona,ou=bird,dc=cartoon,dc=com
298 Where is an entry's name held?
300 Entries do not contain their DN. When you retrieve an entry from a
302 search, the server will tell you the DN of each entry.
303 On the other hand, entries do contain their RDN. Recall that the RDN is
305 formed from one or more attribute-value assertions (AVAs); each entry
306 must contain all the attributes and values in the RDN.
307 For example the entry:
309 cn=Road Runner+l=Arizona,ou=bird,dc=cartoon,dc=com
311 must contain a 'cn' attribute containing at least the value "Road Run‐
313 ner", and an 'l' attribute containing at least the value "Arizona".
314 The attributes used in the RDN may contain additional values, but the
316 entry still only has one DN.
317 What is a search base.
319 A search base is a Distinguished Name that is the starting point of
321 search queries.
322 Example of a DN:
324 cn=Road Runner,ou=bird,dc=cartoon,dc=com
326 Possible search base(s) for the proceeding DN:
328 Base => cn=Road Runner,ou=bird,dc=cartoon,dc=com
330 Base => ou=bird,dc=cartoon,dc=com
331 Base => dc=cartoon,dc=com
332 Base => dc=com
333 Setting the search base to the lowest possible branch of the directory
335 will speed up searches considerably.
336 What is the difference between a LDAP server and a relational database.
338 The most basic difference is that a directory server is a specialized
340 database designed to provide fast searches. While a relational database
341 is optimized for transactions (where a series of operations is counted
342 as 1, thus if one of the steps fails, the RDBMS can roll-back to the
343 state it was in before you started).
344 Directories also typically are hierarchical in nature (RDBMS is typi‐
346 cally flat, but you can implement a hierarchy using tables and
347 queries), networkable, distributed and replicated.
348 LDAP provides an open-standard to a directory service.
350 Typically we use LDAP for email directories (all popular email clients
352 provide an LDAP client now) and authorization services (authentication
353 and access control).
354 You could use a RDBMS for these types of queries but there's no set
356 standard, in particular over TCP/IP to connect to databases over the
357 network. There's language specific protocols (like Perl's DBI and
358 Java's JDBC) that hide this problem behind an API abstraction, but
359 that's not a replacement for a standard access protocol.
360 LDAP is starting to be used on roles traditionally played by RDBMS in
362 terms of general data management because it's easier to setup a LDAP
363 server (once you understand the basic nomenclature) and you don't need
364 a DBA to write your queries and more importantly all LDAP servers speak
365 the same essential protocol, thus you don't have to fuss with a data‐
366 base driver trying to connect it to the Internet. Once you have an LDAP
367 server up and running, it's automatically available over the 'net.
368 It's possible to connect to a LDAP server from a variety of mechanisms,
369 including just about every possible programming language.
370 More information on this topic can be found on the following URLs;
372 http://www.openldap.org/faq/data/cache/378.html
374 http://www.isode.com/whitepapers/ic-6055.html
376 What is the difference between a ldap reference and a ldap referral?
378 A referral is returned when the entire operation must be resent to
380 another server.
381 A continuation reference is returned when part of the operation must be
383 resent to another server.
384 See RFC 2251 section 4.5.3 for more details.
386
388 How do I install perl-ldap ?
389 To install the modules that are in the perl-ldap distribution follow
391 the same steps that you would for most other distributions found on
392 CPAN, that is
393 # replace 0.33 with the version you have
395 gunzip perl-ldap-0.33.tar.gz
397 tar xvf perl-ldap-0.33.tar
398 cd perl-ldap-0.33
399 perl Makefile.PL
401 make
402 make test
403 make install
404 But I do not have make, how can I install perl-ldap ?
406 Well as luck would have it the modules in perl-ldap do not do anything
408 complex, so a simple copy is enough to install. First run
409 perl -V
411 This will output information about the version of perl you have
413 installed. Near the bottom you will find something like
414 @INC:
416 /usr/local/perl/perl5.005/lib/5.00502/sun4-solaris
417 /usr/local/perl/perl5.005/lib/5.00502
418 /usr/local/perl/perl5.005/lib/site_perl/5.005/sun4-solaris
419 /usr/local/perl/perl5.005/lib/site_perl/5.005
420 .
421 This is a list of directories that perl searches when it is looking for
423 a module. The directory you need is the site_perl directory, but with‐
424 out the system architecture name, in this case it is
425 "/usr/local/perl/perl5.005/lib/site_perl/5.005". The files required can
426 then be installed with
427 # replace 0.33 with the version you have
429 gunzip perl-ldap-0.33.tar.gz
431 tar xvf perl-ldap-0.33.tar
432 cd perl-ldap-0.33/lib
433 cp * /usr/local/perl/perl5.005/lib/site_perl/5.005
435 How can I load Perl-LDAP into an ActiveState Perl installation.
437 There are several ways that Perl-LDAP can be installed into an ActiveS‐
439 tate Perl tree.
440 1. The ActiveState ppm command can be used to install Perl-LDAP. When
442 a new version of Perl-LDAP is released, it takes ActiveState a
443 period of time to get the new release into the ActiveState ppm sys‐
444 tem.
445 2. If the user has nmake installed, the user can do a normal perl mod‐
447 ule install using nmake instead of make.
448 3. If the user does not have nmake or make, the user can install Perl-
450 LDAP using the install-nomake script by issuing the following com‐
451 mand.
452 perl install-nomake
454 The install-nomake script can be used on any system that does not
456 have make installed.
457 What other modules will I need ?
459 perl-ldap does use other modules. Some are required, but some are
461 optional (ie required to use certain features)
462 Convert::ASN1
464 This module is required for perl-ldap to work.
465 You can obtain the latest release from
467 http://search.cpan.org/search?module=Convert::ASN1
468 Authen::SASL
470 This module is optional. You only need to install Authen::SASL if
471 you want to use the SASL authentication method.
472 You can obtain the latest release from
474 http://search.cpan.org/search?module=Authen::SASL
475 Digest::MD5
477 This module is optional. It also requires a C compiler when
478 installing. You only need to install Digest::MD5 if you want to
479 use the SASL DIGEST-MD5 authentication method.
480 You can obtain the latest release from
482 http://search.cpan.org/search?module=Digest::MD5
483 URI::ldap
485 This module is optional. You only need to install URI::ldap if you
486 are going to need to parse ldap referrals. Net::LDAP does not do
487 this automatically yet, so this module is not used by perl-ldap.
488 You can obtain the latest release from
490 http://search.cpan.org/search?module=URI::ldap
491 OpenSSL and IO::Socket::SSL for Net::LDAPS
493 If you want to use Net::LDAP::LDAPS you will need this module and
494 the OpenSSL software package.
495 You can obtain the latest release of IO::Socket::SSL from
497 http://search.cpan.org/search?module=IO::Socket::SSL
498 You can obtain the latest release of OpenSSL from
500 http://www.openssl.org/
501 If you are using a Linux system, many of the distributions have RPM
503 packages that you can install. Use your favorite web search engine
504 to find the package that you need.
505 XML::SAX and XML::SAX::Writer
507 If you want to use Net::LDAP::DSML you will need these modules.
508 You can obtain the latest releases from
510 http://search.cpan.org/search?module=XML::SAX
511 http://search.cpan.org/search?module=XML::SAX::Writer
512 ResourcePool::Factory::Net::LDAP
514 If you want to use failover the ResourcePool::Factory::Net::LDAP
515 perl module provides methods to do this.
516 You can obtain the latest release from
518 http://search.cpan.org/search?module=ResourcePool::Fac‐
519 tory::Net::LDAP
520
522 How do I connect to my server ?
523 The connection to the server is created when you create a new Net::LDAP
525 object, e.g.
526 $ldap = Net::LDAP->new($server);
528 Net::LDAP->new sometimes returns undef, why ?
530 The constructor will return undef if there was a problem connecting to
532 the specified server. Any error message will be available in $@
533 What is the proper format of the bind DN.
535 The DN used to bind to a directory is a FULLY QUALIFIED DN. The exact
537 structure of the DN will depend on what data has been stored in the
538 server.
539 The following are valid examples.
541 uid=clif,ou=People,dc=umich,dc=edu
543 cn=directory manager,ou=admins,dc=umich,dc=edu
545 In some servers the following would be a valid fully qualified DN of
547 the directory manager.
548 cn=directory manager
550 How can I tell when the server returns an error, bind() always returns
552 true ?
553 Most methods in Net::LDAP return a Net::LDAP::Message object, or a sub-
555 class of that. This object will hold the results from the server,
556 including the result code.
557 So, for example, to determine the result of the bind operation.
559 $mesg = $ldap->bind( $dn, password => $passwd );
561 if ( $mesg->code ) {
563 # Handle error codes here
564 }
565 How can I set the LDAP version of a connection to my ldap server?
567 This is done by adding the version option when connecting or binding to
569 the LDAP server.
570 For example;
572 $ldap = Net::LDAP->new( $server, version => 3 );
574 or
576 $mesg = $ldap->bind( $dn, password => $passwd, version => 3 );
578 Valid version numbers are 2 and 3. As of perl-ldap 0.27 the default
580 LDAP version is 3.
581 I did a search on my directory using the 'search' method. Where did the
583 results go ?
584 Your search results are stored in a 'search object'. Consider the fol‐
586 lowing:
587 use Net::LDAP;
589 $ldap = Net::LDAP->new('ldap.acme.com') or die "$@";
591 $mesg = $ldap->search(
592 base => "o=acme.com",
593 filter => "uid=jsmith",
594 );
595 $mesg is a search object. It is a reference blessed into the
597 Net::LDAP::Search package. By calling methods on this object you can
598 obtain information about the result and also the individual entries.
599 The first thing to check is if the search was successful. This is done
601 with with the method $mesg->code. This method will return the status
602 code that the server returned. A success will yield a zero value, but
603 there are other values, some of which could also be considered a suc‐
604 cess. See Net::LDAP::Constant
605 use Net::LDAP::Util qw(ldap_error_text);
607 die ldap_error_text($mesg->code)
609 if $mesg->code;
610 There are two ways in which you can access the entries. You can access
612 then with an index or you can treat the container like a stack and
613 shift each entry in turn. For example
614 # as an array
616 # How many entries were returned from the search
618 my $max = $mesg->count;
619 for( my $index = 0 ; $index < $max ; $index++) {
621 my $entry = $mesg->entry($index);
622 # ...
623 }
624 # or as a stack
626 while( my $entry = $mesg->shift_entry) {
628 # ...
629 }
630 In each case $entry is an entry object. It is a reference blessed into
632 the Net::LDAP::Entry package. By calling methods on this object you can
633 obtain information about the entry.
634 For example, to obtain the DN for the entry
636 $dn = $entry->dn;
638 To obtain the attributes that a given entry has
640 @attrs = $entry->attributes;
642 And to get the list of values for a given attribute
644 @values = $entry->get( 'sn' );
646 And to get the first of the values for a given attribute
648 $values = $entry->get( 'cn' );
650 One thing to remember is that attribute names are case insensitive, so
652 'sn', 'Sn', 'sN' and 'SN' are all the same.
653 So, if you want to print all the values for the attribute 'ou' then
655 this is as simple as
656 foreach ($entry->get_value( 'ou' )) {
658 print $_,"\n";
659 }
660 Now if you just want to print all the values for all the attributes you
662 can do
663 foreach my $attr ($entry->attributes) {
665 foreach my $value ($entry->get_value($attr)) {
666 print $attr, ": ", $value, "\n";
667 }
668 }
669 How do I limit the scope of a directory search.
671 You limit the scope of a directory search by setting the scope parame‐
673 ter of search request. Consider the following:
674 use Net::LDAP;
676 $ldap = Net::LDAP->new('ldap.acme.com') or die "$@";
678 $mesg = $ldap->search(
679 base => "o=acme.com",
680 scope => 'sub',
681 filter => "uid=jsmith",
682 );
683 Values for the scope parameter are as follows.
685 base
687 Search only the base object.
688 one Search the entries immediately below the base object.
690 sub Search the whole tree below the base object. This is the default.
692
694 There are two ways of retrieving the results of a requested LDAP
695 search; inline and by using a callback subroutine.
696 USING THE INLINE APPROACH
698 Using the inline approach involves requesting the data and then waiting
700 for all of the data to be returned before the user starts processing
701 the data.
702 Example:
704 use Net::LDAP;
706 $ldap = Net::LDAP->new('ldap.acme.com') or die "$@";
708 $mesg = $ldap->search(
709 base => "o=acme.com",
710 scope => 'sub',
711 filter => "sn=smith",
712 );
713 #
714 # At this point the user can get the returned data as an array
715 # or as a stack.
716 # In this example we will use an array
717 # How many entries were returned from the search
719 my $max = $mesg->count;
720 for( my $index = 0 ; $index < $max ; $index++)
722 {
723 my $entry = $mesg->entry($index);
724 my $dn = $entry->dn; # Obtain DN of this entry
725 @attrs = $entry->attributes; # Obtain attributes for this entry.
727 foreach my $var (@attrs)
728 {
729 #get a list of values for a given attribute
730 $attr = $entry->get_value( $var, asref => 1 );
731 if ( defined($attr) )
732 {
733 foreach my $value ( @$attr )
734 {
735 print "$var: $value\n"; # Print each value for the attribute.
736 }
737 }
738 }
739 }
740 As you can see the example is straight forward, but there is one draw‐
742 back to this approach. You must wait until all entries for the request
743 search to be returned before you can process the data. If there sev‐
744 eral thousand entries that match the search filter this could take
745 quite a long time period.
746 USING THE CALLBACK SUBROUTINE APPROACH
748 Using the callback approach involves requesting the data be sent to a
750 callback subroutine as each entry arrives at the client.
751 A callback is just a subroutine that is passed two parameters when it
753 is called, the mesg and entry objects.
754 Example:
756 use Net::LDAP;
758 $ldap = Net::LDAP->new('ldap.acme.com') or die "$@";
760 $mesg = $ldap->search(
761 base => "o=acme.com",
762 scope => 'sub',
763 filter => "sn=smith",
764 callback => \&callback,
765 );
766 #
767 # At this point the user needs to check the status of the
768 # ldap search.
769 #
770 if ( $mesg->code )
772 {
773 $errstr = $mesg->code;
774 print "Error code: $errstr\n";
775 $errstr = ldap_error_text($errstr);
776 print "$errstr\n";
777 }
778 sub callback
780 {
781 my ( $mesg, $entry) = @_;
782 #
784 # First you must check to see if something was returned.
785 # Last execution of callback subroutine will have no
786 # defined entry and mesg object
787 #
788 if ( !defined($entry) )
789 {
790 print "No records found matching filter $match.\n"
791 if ($mesg->count == 0) ; # if mesg is not defined nothing will print.
792 return;
793 }
794 my $dn = $entry->dn; # Obtain DN of this entry
796 @attrs = $entry->attributes; # Obtain attributes for this entry.
798 foreach my $var (@attrs)
799 {
800 #get a list of values for a given attribute
801 $attr = $entry->get_value( $var, asref => 1 );
802 if ( defined($attr) )
803 {
804 foreach my $value ( @$attr )
805 {
806 print "$var: $value\n"; # Print each value for the attribute.
807 }
808 }
809 }
810 #
811 # For large search requests the following 2 lines of code
812 # may be very important, they will reduce the amount of memory
813 # used by the search results.
814 #
815 # If the user is not worried about memory useage then the 2 lines
816 # of code can be omitted.
817 #
818 $mesg->pop_entry;
819 } # End of callback subroutine
821 As you can see the example is straight forward and it does not waste
823 time waiting for all of the entries to be returned. However if the
824 pop_entry method is not used the callback approach can allocate a lot
825 of memory to the search request.
826
828 Using an SSL network connection, how do I connect to my server?
829 This class is a subclass of Net::LDAP so all the normal Net::LDAP meth‐
831 ods can be used with a Net::LDAPS object; see the documentation for
832 Net::LDAP to find out how to query a directory server using the LDAP
833 protocol.
834 The connection to the server is created when you create a new
836 Net::LDAPS object, e.g.
837 $ldaps = Net::LDAPS->new($server,
839 port => '10000',
840 verify => 'require',
841 capath => '/usr/local/cacerts/',
842 );
843 Starting with version 0.28 perl-ldap also supports URIs in the new
845 method. So, the above can also be expressed as:
846 $ldaps = Net::LDAP->new("ldaps://$server",
848 port => '10000',
849 verify => 'require',
850 capath => '/usr/local/cacerts/',
851 );
852 There are additional options to the new method with LDAPS URIs and the
854 LDAPS new method and several additional methods are included in the
855 LDAPS object class.
856 For further information and code examples read the LDAPS module docu‐
858 mentation; perldoc Net::LDAPS
859
861 What are LDAP groups.
862 LDAP groups are object classes that contain an attribute that can store
864 multiple DN values. Two standard object classes are 'groupOfNames'
865 (which has a 'member' attribute) and 'groupOfUniqueNames' (which has a
866 'uniqueMember' attribute.)
867 According to the RFCs a group can be a member of another group, but
869 some LDAP server vendors restrict this flexibility by not allowing
870 nested groups in their servers.
871 Two scripts for working with groups are available in the contrib direc‐
873 tory. They are isMember.pl and printMembers.pl.
874 How do you format a filter to search for entries whose 'member'
876 attribute has a particular value?
877 Asking for (member=*) is OK - the directory uses the equality matching
879 rule which is defined for the member attribute.
880 Asking for (member=c*) is not OK - there is no defined substring match‐
882 ing rule for the member attribute. That's because the member values are
883 *not* strings, but distinguished names. There is no substring matching
884 rule for DNs, see RFC 2256 section 5.50.
885 What you have to do is get the results of (member=*) and then select
887 the required results from the returned values. You need to do this
888 using knowledge of the string representation of DNs defined in RFC
889 2253, which is important because the same DN can have different string
890 representations. So you need to perform some canonicalization if you
891 want to be correct.
892
894 How can I access DSML features from PERL-LDAP.
895 Directory Service Markup Language (DSML) is the XML standard for repre‐
897 senting directory service information in XML.
898 Support for DSML is included in PERL-LDAP starting with version .20.
900 At the moment this module only reads and writes DSML entry entities. It
902 cannot process any schema entities because schema entities are pro‐
903 cessed differently than elements.
904 Eventually this module will be a full level 2 consumer and producer
906 enabling you to give you full DSML conformance.
907 The specification for DSML is at http://www.oasis-open.org/specs/
909 For further information and code examples read the DSML module documen‐
911 tation; perldoc Net::LDAP::DSML
912
914 How do I access the Control features.
915 Support for LDAP version 3 Control objects is included in perl-ldap
917 starting with version .20.
918 For further information and code examples read the Control module docu‐
920 mentation; perldoc Net::LDAP::Control
921 How do I access the Virtual List features.
923 Support for Virtual Lists is included in perl-ldap starting with ver‐
925 sion .20.
926 For further information and code examples read the Control module docu‐
928 mentation; perldoc Net::LDAP::Control
929
931 Are there any other code examples.
932 Yes, there is an Examples pod file. To view the pod do the following
934 command; perldoc Net::LDAP::Examples
935 There is user contributed software in the contrib directory that is
937 supplied with the PERL-LDAP distribution. This is an excellent source
938 of information on how to use the PERL-LDAP module.
939 Are there any performance issues with perl-ldap ?
941 In the vast majority of use cases (one user has suggested 9 out of 10)
943 there are no performance issues with perl-ldap.
944 Where you may wish to use perl-ldap to perform, for example, a very
946 large number of queries (e.g. 10,000) in succession you may find a
947 noticeable performance difference between perl-ldap and non pure-perl
948 modules. This is not because of perl-ldap itself but because of the
949 pure-perl Convert::ASN1 module that it depends on.
950 You should make up your own mind, based upon your own situation (per‐
952 formance requirements, hardware etc.) as to whether you should use
953 perl-ldap or not. The figures quoted in this answer are only indica‐
954 tive, and will differ for different people.
955 Can I contribute perl scripts that use perl-ldap to the contrib sec‐
957 tion?
958 Any one can submit a perl script that uses perl-ldap for inclusion in
960 the contrib section. Graham Barr will determine if the script will be
961 included and will do the initial check in of the script to the SVN sys‐
962 tem on http://svn.mutatus.co.uk. Graham will make you the owner/devel‐
963 oper of the script.
964 There are a couple of requirements for consideration.
966 You must supply a one line description of your script to be included in
968 the contrib readme file.
969 Inside the script will be the pod documentation for the script. No
971 auxiliary documentation will be allowed. For examples of how to do
972 this see the tklkup script currently in the contrib section.
973 Is it possible to get a complete entry, DN and attributes without spec‐
975 ifying the attributes name?
976 Yes, just specify you want a list of no attributes back. The RFC says
978 that this tells the server to return all readable attributes back
979 (there may be access controls to prevent some from being returned.)
980 So in the search method, just set (for LDAPv2):
982 attrs => [ ]
984 If you are using LDAPv3, you can specify an attribute called "*"
986 instead, which lets you ask for additional (i.g. operational)
987 attributes in the same search.
988 attrs => [ "*" ]
990 To get all operational attributes in a search, some servers allow the
992 use of the "+" pseudo attribute. So that with these servers
993 attrs => [ "*", "+" ]
995 will return the most information from the server.
997 How do I put a JPEG photo into a entry in the directory.
999 Follow the following code example, replacing the (...) with whatever is
1001 relevant to your setup.
1002 use Net::LDAP;
1004 use Net::LDAP::Util qw(ldap_error_text);
1005 use CGI;
1006 local $/ = undef;
1008 my $jpeg = <$filename>;
1009 my $ldap = Net::LDAP->new(...);
1011 my $res = $ldap->bind(...);
1012 $res = $ldap->modify(...,
1013 add => [ 'jpegPhoto' => [ $jpeg ] ]);
1014 $res = $ldap->unbind();
1015 How do I add a jpeg photo into a entry in the directory via html-forms.
1017 Follow the following code example, replacing the (...) with whatever is
1019 relevant to your setup.
1020 use Net::LDAP;
1022 use Net::LDAP::Util qw(ldap_error_text);
1023 use CGI;
1024 my $q = new CGI;
1026 print $q->header;
1028 print $q->start_html(-title => 'Change JPEG photo');
1029 if ($q->param('Update')) {
1031 my $filename = $q->param('jpeg');
1032 local $/ = undef;
1033 my $jpeg = <$filename>;
1034 my $ldap = Net::LDAP->new(...);
1036 my $res = $ldap->bind(...);
1037 $res = $ldap->modify(...,
1038 add => [ 'jpegPhoto' => [ $jpeg ] ]);
1039 $res = $ldap->unbind();
1040 } else {
1041 print $q->start_multipart_form();
1042 print $q->filefield(-name => 'jpeg', -size => 50);
1043 print $q->submit('Update');
1044 print $q->end_form();
1045 }
1046 print $q->end_html();
1048 What happens when you delete an attribute that does not exist.
1050 It is an error to delete an attribute that doesn't exist. When you get
1052 the error back the server ignores the entire modify operation you sent
1053 it, so you need to make sure the error doesn't happen.
1054 Another approach, if you are using LDAPv3 (note beginning with version
1056 .27 Net::LDAP uses LDAPv3 by default) is to use a 'replace' with your
1057 attribute name and no values. In LDAPv3, this is defined to always
1058 work even if that attribute doesn't exist in the entry.
1059 ie:
1061 my $mesg = $ldap->modify( $entry, replace => { %qv_del_arry } );
1063 But make sure you are using LDAPv3, because that is defined to not work
1065 in LDAPv2. (A nice incompatibility between LDAPv2 and LDAPv3.)
1066 How can I delete a referral from an LDAP tree.
1068 Since this is a proprietary feature, you will have to check your
1070 server's documentation. You might find that you need to use a control.
1071 If there is a control called something like managedsait, that's the one
1072 you should probably use. For proper operation you will need the oid
1073 number for managedsait; 2.16.840.1.113730.3.4.2 and do not specify a
1074 value for type.
1075 The code required will look similar to the following code snippet.
1077 $mesg = $ldap->delete("ref=\"ldap://acme/c=us,o=bricks\",o=clay",
1079 control => {type => "2.16.840.1.113730.3.4.2"} );
1080 How do I add an ACI/ACL entry to a directory server with Perl-LDAP.
1082 ACIs and ACLs are proprietary features in LDAP. The following code
1084 snippet works with a Netscape directory server. You will need the spec‐
1085 ify the correct DN (-DN-) and correct attribute(s) (-nom attr-).
1086 my $aci = '(target="ldap:///-DN-")(targetattr="-nom attr-")(version 3.0;
1088 acl "-nom acl-"; deny(all) userdn = "ldap:///self";)' ;
1089 $ldap->modify($dn_modif, add => {'aci' => $aci });
1091 How do I avoid file type and data type mis-matching when loading data
1093 from a Win32 system.
1094 When loading a binary attribute with data read from a file on a Win32
1096 system, it has been noted that you should set "binmode" on the file
1097 before reading the file contents into the data array.
1098 Another possible solution to this problem is to convert the binary data
1100 into a base64 encoded string and then store the encoded string in the
1101 file. Then when reading the file, decode the base64 encoded string
1102 back to binary and then use perl ldap to store the data in the direc‐
1103 tory.
1104 How do I create a Microsoft Exchange 5.x user.
1106 This is a solution provide by a perl-ldap user.
1108 This code works with ActiveState Perl running on WinNT 4. Please note
1110 that this requires the Win32::Perms module, and needs valid NT account
1111 info to replace the placeholders.
1112 use Net::LDAP;
1114 use Net::LDAP::Util;
1115 use Win32::Perms;
1116 #Constants taken from ADSI Type Library
1118 $ADS_RIGHT_EXCH_ADD_CHILD = 1;
1119 $ADS_RIGHT_EXCH_DELETE = 0x10000;
1120 $ADS_RIGHT_EXCH_DS_REPLICATION = 64;
1121 $ADS_RIGHT_EXCH_DS_SEARCH = 256;
1122 $ADS_RIGHT_EXCH_MAIL_ADMIN_AS = 32;
1123 $ADS_RIGHT_EXCH_MAIL_RECEIVE_AS = 16;
1124 $ADS_RIGHT_EXCH_MAIL_SEND_AS = 8;
1125 $ADS_RIGHT_EXCH_MODIFY_ADMIN_ATT = 4;
1126 $ADS_RIGHT_EXCH_MODIFY_SEC_ATT = 128;
1127 $ADS_RIGHT_EXCH_MODIFY_USER_ATT = 2;
1128 $EXCH_USER_RIGHTS = $ADS_RIGHT_EXCH_MAIL_RECEIVE_AS ⎪
1130 $ADS_RIGHT_EXCH_MAIL_SEND_AS ⎪
1131 $ADS_RIGHT_EXCH_MODIFY_USER_ATT;
1132 $exch = Net::LDAP->new('server', debug =>0) ⎪⎪ die $@;
1134 $exch->bind( 'cn=admin_user,cn=nt_domain,cn=admin', version =>3,
1136 password=>'password');
1137 $myObj = Win32::Perms->new();
1139 $Result = $myObj->Owner('nt_domain\user_name');
1140 $myObj->Group('nt_domain\Everyone');
1141 $myObj->Allow('nt_domain\user_name',
1142 $EXCH_USER_RIGHTS,OBJECT_INHERIT_ACE);
1143 $BinarySD = $myObj->GetSD(SD_RELATIVE);
1144 $TextSD = uc(unpack( "H*", $BinarySD ));
1145 Win32::Perms::ResolveSid('nt_domain\user_name', $sid);
1146 $mysid = uc(unpack("H*",$sid));
1147 $result = $exch->add ( dn =>
1149 'cn=user_name,cn=container,ou=site,o=organisation',
1150 attr => [ 'objectClass' => ['organizationalPerson'],
1151 'cn' => 'directory_name',
1152 'uid' => 'mail_nickname',
1153 'mail' => 'smtp_address',
1154 'assoc-nt-account' => [ $mysid ],
1155 'nt-security-descriptor' => [ $TextSD ],
1156 'mailPreferenceOption' => 0
1157 ]
1158 );
1159 print ldap_error_name($result->code);
1161 Ho do I reset a user's password ...
1163 ... in most LDAP servers ?
1165 Most LDAP servers use the standard userPassword attribute as the
1167 attribute to set when you want to change a user's password.
1168 They usually allow to set the password either using the regular modify
1170 operation on the userPassword attribute or using the extended LDAP
1171 Password Modify operation defined in RFC3062.
1172 The recommended method is the extended Password Modify operation, which
1174 offers a standardized way to set user passwords but unfortunately is
1175 not available on all LDAP servers.
1176 Whether the extended Password Modify operation is available can be
1178 found out by searching the attribute supportedExtension for the value
1179 1.3.6.1.4.1.4203.1.11.1 in the RootDSE object.
1180 If the extended Password Modify operation is not avaiable the alterna‐
1182 tive is the regular modification of the userPassword attribute.
1183 But this method has some drawbacks:
1185 · Depending on the type of the server the arguments to the modify
1187 operations may vary. Some want the modify done with replace, some
1188 want it done by explicitely deleting the old password and add of
1189 the new one. This may even depend on whether you change the pass‐
1190 word for the bound user or as an administrator for another user.
1191 · With the modify operation some servers expect the client to do the
1193 hashing of the password on the client side. I.e. all clients that
1194 set passwords need to agree on the algorithm and the format of the
1195 hashed password.
1196 · Some LDAP servers do not allow setting the password if the connec‐
1198 tion is not sufficiently secured. I.e. require SSL or TLS support
1199 to set the password (which is heavily recommended anyway ;-)
1200 Here is an example of how to change your own password (for brevity's
1202 sake error checking is left out):
1203 use Net::LDAP;
1205 my $ldap = Net::LDAP->new('ldaps://server.domain') or die "$@";
1207 my $mesg = $ldap->bind('cn=Joe User,dc=perl,dc=ldap,dc=org',
1208 password => 'oldPW');
1209 my $rootdse = $ldap->root_dse();
1211 if ($rootdse->supported_extension('1.3.6.1.4.1.4203.1.11.1') {
1213 require Net::LDAP::Extension::SetPassword;
1215 $mesg = $ldap->set_password(user => 'cn=Joe User,dc=perl,dc=ldap,dc=org',
1217 oldpasswd => 'oldPW',
1218 newpasswd => 'newPW');
1219 }
1220 else {
1221 $mesg = $ldap->modify('cn=Joe User,dc=perl,dc=ldap,dc=org',
1222 changes => [
1223 delete => [ userPassword => $oldPW ]
1224 add => [ userPassword => $newPW ] ]);
1225 }
1226 $ldap->unbind();
1228 ... in MS Active Directory ?
1230 With Active Directory a user's password is stored in the unicodePwd
1232 attribute and changed using the regular modify operation.
1233 ADS expects this password to be encoded in Unicode - UTF-16 to be
1235 exact. Before the unicode conversion is done the password needs to be
1236 surrounded by double quotes which do not belong to the user's password.
1237 For the password modify operation to succeed SSL is required.
1239 When changing the password for the user bound to the directory ADS
1241 expects it to be done by deleting the old password and adding the new
1242 one. When doing it as a user with administrative priviledges replacing
1243 the unicodePwd's value with a new one is allowed too.
1244 Here's an example that demonstrates setting your own password (again
1246 almost no error checking):
1247 use Net::LDAP;
1249 use Unicode::Map8;
1250 use Unicode::String qw(utf16);
1251 # build the conversion map from your local character set to Unicode
1253 my $charmap = Unicode::Map8->new('latin1') or die;
1254 # surround the PW with double quotes and convert it to UTF-16
1256 # byteswap() was necessary in experiments on i386 Linux, YMMV
1257 my $oldUniPW = $charmap->tou('"'.$oldPW.'"')->byteswap()->utf16();
1258 my $newUniPW = $charmap->tou('"'.$newPW.'"')->byteswap()->utf16();
1259 my $ldap = Net::LDAP->new('ldaps://ads.domain.controller') or die "$@";
1261 my $mesg = $ldap->bind('cn=Joe User,dc=your,dc=ads,dc=domain',
1263 password => 'oldPW');
1264 $mesg = $ldap->modify('cn=Joe User,dc=your,dc=ads,dc=domain',
1266 changes => [
1267 delete => [ unicodePwd => $oldUniPW ]
1268 add => [ unicodePwd => $newUniPW ] ]);
1269 $ldap->unbind();
1271 How can I simulate server failover.
1273 Perl-LDAP does not do server failover, however there are several pro‐
1275 gramming options for getting around this situation.
1276 Here is one possible solution.
1278 unless ( $ldaps =
1280 Net::LDAPS->new($ldapserverone,
1281 port=>636,timeout=>5) )
1282 {
1283 $ldaps = Net::LDAPS->new($ldapservertwo,
1284 port=>636,timeout=>20) ⎪⎪
1285 return
1286 "Can't connect to $ldapserverone or $ldapservertwo via LDAPS: $@";
1287 }
1288 As of version 0.27 of perl-ldap the above can be expressed much sim‐
1290 pler:
1291 $ldaps = Net::LDAPS->new([ $ldapserverone, $ldapservertwo ],
1293 port=>636, timeout=>5) or die "$@";
1294
1296 How do I store X.509 certificates in the directory?
1297 The first problem here is that there are many different formats to hold
1299 certificates in, for example PEM, DER, PKCS#7 and PKCS#12. The direc‐
1300 tory only uses the DER format (more correctly, it only uses the BER
1301 format) which is a binary format.
1302 Your first job is to ensure that your certificates are therefore in
1304 DER/BER format. You could use OpenSSL to convert from PEM like this:
1305 openssl x509 -inform PEM -in cert.pem -outform DER -out cert.der
1307 Consult the OpenSSL documentation to find out how to perform other con‐
1309 versions.
1310 To add a certificate to the directory, just slurp in the DER/BER cer‐
1312 tificate into a scalar variable, and add it to the entry's userCertifi‐
1313 cate attribute. How you do that will depend on which version of LDAP
1314 you are using.
1315 To slurp in the certificate try something like this:
1317 my $cert;
1319 {
1320 local $/ = undef; # Slurp mode
1321 open CERT, "cert.der" or die;
1322 binmode CERT;
1323 $cert = <CERT>;
1324 close CERT;
1325 }
1326 # The certificate is now in $cert
1327 For LDAPv2, because most directory vendors ignore the string represen‐
1329 tation of certificates defined in RFC 1778, you should add this value
1330 to the directory like this:
1331 $res = $ldap->modify("cn=My User, o=My Company,c=XY",
1333 add => [
1334 'userCertificate' => [ $cert ]
1335 ]);
1336 die "Modify failed (" . ldap_error_name($res->code) . ")\n"
1337 if $res->code;
1338 For LDAPv3, you must do this instead:
1340 $res = $ldap->modify("cn=My User, o=My Company, c=XY",
1342 add => [
1343 'userCertificate;binary' => [ $cert ]
1344 ]);
1345 die "Modify failed (" . ldap_error_name($res->code) . ")\n"
1346 if $res->code;
1347 Of course, the entry you are trying to add the certificate to must use
1349 object classes that permit the userCertificate attribute, otherwise the
1350 modify will fail with an object class violation error. The inetOrgPer‐
1351 son structural object class permits userCertificates, as does the
1352 strongAuthenticationUser auxiliary object class. Others might also.
1353
1355 URLs.
1356 Directory Services Mark Language (DSML)
1358 http://www.oasis-open.org/specs/
1359 eMailman LDAP information http://www.emailman.com/ldap/
1361 Rafael Corvalan's LDAP shell http://sf.net/projects/ldapsh
1363 LDAPS, also known as LDAPGURU. This web site has a nasty habit of
1365 resizing the browser to cover the WHOLE screen. http://www.ldaps.com
1366 Jeff Hodges's Kings Mountain LDAP http://www.kingsmoun‐
1368 tain.com/ldapRoadmap.shtml
1369 Mark Wahl's LDAP World at Innosoft. http://www.innosoft.com/ldapworld/
1371 (outdated: last update was in 1998)
1372 Open Source LDAP Directory Server. http://www.openldap.org/
1374 CriticalPath http://www.cp.net/
1376 IBM Directory Server http://www-306.ibm.com/software/network/direc‐
1378 tory/server/
1379 Innosoft http://www.innosoft.com (acquired by Sun)
1381 Isode (was MessagingDirect) http://www.isode.com/
1383 Netscape Directory Developers Area http://developer.netscape.com/direc‐
1385 tory/
1386 Nexor's X.500 and Internet Directories http://www.nexor.com/info/direc‐
1388 tory.htm/
1389 Novell's eDirectory http://www.novell.com/
1391 Novell's LDAPzone http://ldapzone.com/
1393 Octet String http://www.octetstring.com/
1395 SUN JAVA JNDI (Java Naming and Directory Interface)
1397 http://www.java.sun.com/jndi/
1398 Sun One, formerly Iplanet. http://wwws.sun.com/software/
1400 Eine deutsche LDAP Website A german LDAP Website http://verzeichnisdi‐
1402 enst.de/ldap/Perl/index.html
1403 The 2 following URLs deal mainly with Microsoft's Active Directory.
1405 Directory Works http://directoryworks.com/
1407 ActiveX LDAP Client http://www.polonia-online.com/ldap/
1409 BOOKS
1411 Developing LDAP and ADSI Clients for Microsoft(R) Exchange. By Sven B.
1413 Schreiber. ISBN: 0201657775
1414 Implementing LDAP. By Mark Wilcox. ISBN: 1861002211
1416 LDAP: Programming Directory-Enabled Applications With Lightweight
1418 Directory Access Protocol. By Tim Howes, Mark Smith. ISBN:
1419 1578700000
1420 LDAP Programming; Directory Management and Integration. By Clayton
1422 Donley. ISBN: 1884777910
1423 LDAP Programming with Java. By Rob Weltman, Tony Dahbura. ISBN:
1425 0201657589
1426 LDAP System Administration. By Gerald Carter. ISBN: 1565924916
1428 Managing Enterprise Active Directory Services. By Robbie Allen,
1430 Richard Puckett. ISBN: 0672321254
1431 Solaris and LDAP Naming Services. By Tom Bialaski, Michael Haines.
1433 ISBN: 0-13-030678-9
1434 Understanding and Deploying LDAP Directory Services (2ed). By Tim
1436 Howes, Mark Smith, Gordon Good. ISBN: 0672323168
1437 LDAP Directories Explained. By Brian Arkills. ISBN 0-201-78792-X
1439
1441 Any good FAQ is made up of many authors, everyone that contributes
1442 information to the perl-ldap mail list is a potential author.
1443 An attempt to maintain this FAQ is being done by Chris Ridd
1445 <chris.ridd@isode.com> and Peter Marschall <peter@adpm.de>. It was
1446 previously updated by Clif Harden <charden@pobox.com>.
1447 The original author of this FAQ was Graham Barr <gbarr@pobox.com>
1449 Please report any bugs, or post any suggestions, to the perl-ldap mail‐
1451 ing list <perl-ldap@perl.org>.
1452
1454 Copyright (c) 1999-2004 Graham Barr. All rights reserved. This document
1455 is distributed, and may be redistributed, under the same terms as Perl
1456 itself.
1457perl v5.8.8 2007-02-10 Net::LDAP::FAQ(3)