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
22 the Net::LDAP modules.
23 Why another perl LDAP implementation ?
25 perl-ldap's goal is to be as portable as possible. It does this by
26 being implemented completely in perl. So basically anywhere that perl
27 runs perl-ldap will run. This is not true for other implementations
28 which require a C compiler.
29 Where can I get it ?
31 Perl-ldap is available from CPAN. You will find it in the
32 authors/id/GBARR directory. Alternatively you can download the latest
33 version from
34 http://www.cpan.org/search?dist=perl-ldap
36 WARNING: The perl-ldap module is stored on CPAN as a *.gz file.
38 Netscape on Windows systems sometimes has a problem storing the module
39 with the correct name, it will replace the *.tar.gz with *_tar.tar. To
40 correct the problem, with the pointer on the link, do a right click and
41 then select save link as to save the file with the correct file name.
42 Is there a web page for perl-ldap ?
44 Yes there is at http://ldap.perl.org/
45 Is there a mailing list ?
47 Yes there is at perl-ldap@perl.org
48 You can subscribe to this list by mailing perl-ldap-subscribe@perl.org
50 Is the mailing list archived ?
52 Yes, at http://nntp.perl.org/group/perl.ldap
53 Archives with messages before we switched to using perl.org can be
55 found at
56 http://marc.theaimsgroup.com/?l=perl-ldap-dev
58 There is also an archive of the perl-ldap mailing list at
60 http://www.xray.mpe.mpg.de/mailing-lists/perl-ldap/
62 which also has messages from before the move.
64 Is there any online documentation ?
66 Yes. perl-ldap has online documentation at
67 http://ldap.perl.org/
69 which will have the latest documentation available.
71 Is there a public CVS repository ?
73 No, but there is a public SVN repository at
74 http://svn.mutatus.co.uk
76 Can I get perl-ldap from the public SVN repository?
78 Yes, any one can pull perl-ldap from the public SVN repository on
79 perl.ldap.org.
80 There are several ways this can be done.
82 Web You can download it from CPAN by following the release link:
84 The 2 lines in the following example should be put together as one
86 continuous line. Example;
87 http://search.cpan.org/CPAN/authors/id/G/GB/GBARR/perl-ldap-0.33.tar.gz
89 WARNING: The perl-ldap module is stored on CPAN as a *.gz file.
91 Netscape on Windows systems sometimes has a problem storing the
92 module with the correct name, it will replace the *.tar.gz with
93 *_tar.tar. To correct the problem, with the pointer on the link,
94 do a right click and then select save link as to save the file with
95 the correct file name.
96 SVN You can download latest development version of perl-ldap from
98 svn.mutatus.co.uk by executing a anonymous SVN "checkout" command.
99 The 2 lines in the following example should be put together as one
101 continuous line. Example;
102 svn co http://svn.mutatus.co.uk/repos/perl-ldap/trunk
104 Web page
106 Most of the time there is a URL link on the perl-ldap home page on
107 ldap.perl.org that points to the latest released version of perl-
108 ldap. Due to the fact that humans must update the web page to
109 point to a new release it sometimes does not get updated as quickly
110 as it should.
111 WARNING: The perl-ldap module is stored on CPAN as a *.gz file.
113 Netscape on Windows systems sometimes has a problem storing the
114 module with the correct name, it will replace the *.tar.gz with
115 *_tar.tar. To correct the problem, with the pointer on the link,
116 do a right click and then select save link as to save the file with
117 the correct file name.
118 What is SVN.
120 "SVN" is an abbreviation for "Subversion" (see
121 http://subversion.tigris.org). Subversion is a "Source Control" or
122 "Revision Control" tool designed to keep track of source changes made
123 by groups of developers working on the same files, allowing them to
124 stay in sync with each other as each individual chooses.
125
127 In order to help the user understand the perl-ldap module better some
128 key LDAP terminology is defined here.
129 What is a directory.
131 A directory is a special purpose hierarchical database that usually
132 contains typed information such as text strings, binary data, or X.509
133 certificates.
134 What is LDAP.
136 LDAP stands for Lightweight Directory Access Protocol. The word
137 Protocol is the key word in the definition given in the preceding
138 sentence, LDAP is NOT hardware or software. It is a protocol that
139 defines how a client and server will communicate with one another.
140 The Lightweight Directory Access Protocol is defined in a series of
142 Requests For Comments, better known as RFCs. The RFCs can be found on
143 the Internet at http://www.ietf.org/ (the master repository) and many
144 other places. There's a link to all the LDAP-related RFCs at Perl-
145 LDAP's web site, http://ldap.perl.org/rfc.html. Some of the more
146 important RFC numbers are RFC 451i0 - 4519 for LDAP (previously called
147 LDAPv3) and the historic RFC 1777 for LDAPv2.
148 What is a LDAP Directory.
150 In the strictest terms of the definition there is no such thing as a
151 LDAP directory. To be practical about this situation every day
152 directory professionals refer to their directory as " a LDAP directory"
153 because it is easy to say and it does convey the type of protocol used
154 to communicate with their directory. Using this definition a LDAP
155 directory is a directory whose server software conforms to the
156 Lightweight Directory Access Protocol when communicating with a client.
157 What is an Entry.
159 The traditional directory definition of a directory object is called an
160 Entry. Entries are composed of attributes that contain the information
161 to be recorded about the object.
162 (An entry in LDAP is somewhat analogous to a record in a table in an
164 SQL database, but don't get too hung up about this analogy!)
165 Entries are held in an upside-down tree structure. Entries can
167 therefore contain subordinate entries, and entries must have one direct
168 superior entry.
169 Entries with subordinate entries are called 'non-leaf' entries.
171 Entries without subordinate entries are called 'leaf' entries.
173 An entry's direct superior entry is called the entry's 'parent'.
175 'Non-leaf' entries are also said to have 'child' entries.
177 What is an attribute.
179 The entry(s) in a directory are composed of attributes that contain
180 information about the object. Each attribute has a type and can
181 contain one or more values.
182 For example:
184 cn=Road Runner
186 is an attribute with a type named "cn", and one value.
188 Each attribute is described by a 'syntax' which defines what kind of
190 information can be stored in the attributes values. Trying to store a
191 value that doesn't conform to the attribute's syntax will result in an
192 error.
193 For example:
195 jpegPhoto=unknown
197 is not permitted by the directory, because jpegPhotos may only contain
199 JPEG-formatted images.
200 Most syntaxes used in LDAP however describe text strings rather than
202 binary objects (like JPEGs or certificates.)
203 In LDAPv3 most of these syntaxes support Unicode encoded using UTF-8.
205 Because the Net::LDAP modules do not change the strings that you pass
206 in as attribute values (they get sent to the LDAP server as-is) to use
207 accented characters you simply need to encode your strings in UTF-8.
208 There are modules on CPAN that will help you here.
209 Note that LDAPv2 servers used something called T.61 instead of Unicode
211 and UTF-8. Most servers do not implement T.61 correctly, and it is
212 recommended that you use LDAPv3 instead.
213 Attributes may also be searched. The algorithms used to perform
215 different kinds of searches are described by the attribute's 'matching
216 rules'. Some matching rules are case-sensitive and some are case-
217 insensitive, for example. Sometimes matching rules aren't defined for
218 a particular attribute: there's no way to search for jpegPhotos that
219 contain a substring!
220 You can examine all of a server's attribute definitions by reading the
222 schema from the server.
223 What is an object class.
225 An object class is the name associated with a group of attributes that
226 must be present in an entry, and the group of attributes that may also
227 be present in an entry.
228 Object classes may be derived (subclassed) from other object classes.
230 For example the widely used 'inetOrgPerson' object class is derived
231 from 'organizationalPerson', which is itself derived from 'person'
232 which is itself derived from 'top'.
233 Every entry has an attribute called 'objectClass' that lists all the
235 names of object classes (and their superclasses) being used with the
236 entry.
237 You can examine all of a server's objectclass definitions by reading
239 the schema from the server.
240 What is a Distinguished Name (DN).
242 Every entry in a directory has a Distinguished Name, or DN. It is a
243 unique Entry identifier throughout the complete directory. No two
244 Entries can have the same DN within the same directory.
245 Examples of DNs:
247 cn=Road Runner, ou=bird, dc=cartoon, dc=com
249 ou=bird, dc=cartoon, dc=com
250 dc=cartoon, dc=com
251 dc=com
252 What is a Relative Distinguished Name.
254 Every DN is made up of a sequence of Relative Distinguished Names, or
255 RDNs. The sequences of RDNs are separated by commas (,). In LDAPv2
256 semi-colons (;) were also allowed. There can be more than one
257 identical RDN in a directory, but they must have different parent
258 entries.
259 Technically, an RDN contains attribute-value assertions, or AVAs. When
261 an AVA is written down, the attribute name is separated from the
262 attribute value with an equals (=) sign.
263 Example of a DN:
265 cn=Road Runner,ou=bird,dc=cartoon,dc=com
267 RDNs of the proceeding DN:
269 RDN => cn=Road Runner
270 RDN => ou=bird
271 RDN => dc=cartoon
272 RDN => dc=com
273 RDNs can contain multiple attributes, though this is somewhat unusual.
275 They are called multi-AVA RDNs, and each AVA is separated in the RDN
276 from the others with a plus sign (+).
277 Example of a DN with a multi-AVA RDN:
279 cn=Road Runner+l=Arizona,ou=bird,dc=cartoon,dc=com
281 Where is an entry's name held?
283 Entries do not contain their DN. When you retrieve an entry from a
284 search, the server will tell you the DN of each entry.
285 On the other hand, entries do contain their RDN. Recall that the RDN is
287 formed from one or more attribute-value assertions (AVAs); each entry
288 must contain all the attributes and values in the RDN.
289 For example the entry:
291 cn=Road Runner+l=Arizona,ou=bird,dc=cartoon,dc=com
293 must contain a 'cn' attribute containing at least the value "Road
295 Runner", and an 'l' attribute containing at least the value "Arizona".
296 The attributes used in the RDN may contain additional values, but the
298 entry still only has one DN.
299 What is a search base.
301 A search base is a Distinguished Name that is the starting point of
302 search queries.
303 Example of a DN:
305 cn=Road Runner,ou=bird,dc=cartoon,dc=com
307 Possible search base(s) for the proceeding DN:
309 Base => cn=Road Runner,ou=bird,dc=cartoon,dc=com
311 Base => ou=bird,dc=cartoon,dc=com
312 Base => dc=cartoon,dc=com
313 Base => dc=com
314 Setting the search base to the lowest possible branch of the directory
316 will speed up searches considerably.
317 What is the difference between a LDAP server and a relational database.
319 The most basic difference is that a directory server is a specialized
320 database designed to provide fast searches. While a relational database
321 is optimized for transactions (where a series of operations is counted
322 as 1, thus if one of the steps fails, the RDBMS can roll-back to the
323 state it was in before you started).
324 Directories also typically are hierarchical in nature (RDBMS is
326 typically flat, but you can implement a hierarchy using tables and
327 queries), networkable, distributed and replicated.
328 LDAP provides an open-standard to a directory service.
330 Typically we use LDAP for email directories (all popular email clients
332 provide an LDAP client now) and authorization services (authentication
333 and access control).
334 You could use a RDBMS for these types of queries but there's no set
336 standard, in particular over TCP/IP to connect to databases over the
337 network. There's language specific protocols (like Perl's DBI and
338 Java's JDBC) that hide this problem behind an API abstraction, but
339 that's not a replacement for a standard access protocol.
340 LDAP is starting to be used on roles traditionally played by RDBMS in
342 terms of general data management because it's easier to setup a LDAP
343 server (once you understand the basic nomenclature) and you don't need
344 a DBA to write your queries and more importantly all LDAP servers speak
345 the same essential protocol, thus you don't have to fuss with a
346 database driver trying to connect it to the Internet. Once you have an
347 LDAP server up and running, it's automatically available over the 'net.
348 It's possible to connect to a LDAP server from a variety of mechanisms,
349 including just about every possible programming language.
350 More information on this topic can be found on the following URLs;
352 http://www.openldap.org/faq/data/cache/378.html
354 http://www.isode.com/whitepapers/ic-6055.html
356 What is the difference between a ldap reference and a ldap referral?
358 A referral is returned when the entire operation must be resent to
359 another server.
360 A continuation reference is returned when part of the operation must be
362 resent to another server.
363 See RFC 2251 section 4.5.3 for more details.
365
367 How do I install perl-ldap ?
368 To install the modules that are in the perl-ldap distribution follow
369 the same steps that you would for most other distributions found on
370 CPAN, that is
371 # replace 0.33 with the version you have
373 gunzip perl-ldap-0.33.tar.gz
375 tar xvf perl-ldap-0.33.tar
376 cd perl-ldap-0.33
377 perl Makefile.PL
379 make
380 make test
381 make install
382 But I do not have make, how can I install perl-ldap ?
384 Well as luck would have it the modules in perl-ldap do not do anything
385 complex, so a simple copy is enough to install. First run
386 perl -V
388 This will output information about the version of perl you have
390 installed. Near the bottom you will find something like
391 @INC:
393 /usr/local/perl/perl5.005/lib/5.00502/sun4-solaris
394 /usr/local/perl/perl5.005/lib/5.00502
395 /usr/local/perl/perl5.005/lib/site_perl/5.005/sun4-solaris
396 /usr/local/perl/perl5.005/lib/site_perl/5.005
397 .
398 This is a list of directories that perl searches when it is looking for
400 a module. The directory you need is the site_perl directory, but
401 without the system architecture name, in this case it is
402 "/usr/local/perl/perl5.005/lib/site_perl/5.005". The files required can
403 then be installed with
404 # replace 0.33 with the version you have
406 gunzip perl-ldap-0.33.tar.gz
408 tar xvf perl-ldap-0.33.tar
409 cd perl-ldap-0.33/lib
410 cp * /usr/local/perl/perl5.005/lib/site_perl/5.005
412 How can I load Perl-LDAP into an ActiveState Perl installation.
414 There are several ways that Perl-LDAP can be installed into an
415 ActiveState Perl tree.
416 1. The ActiveState ppm command can be used to install Perl-LDAP. When
418 a new version of Perl-LDAP is released, it takes ActiveState a
419 period of time to get the new release into the ActiveState ppm
420 system.
421 2. If the user has nmake installed, the user can do a normal perl
423 module install using nmake instead of make.
424 3. If the user does not have nmake or make, the user can install Perl-
426 LDAP using the install-nomake script by issuing the following
427 command.
428 perl install-nomake
430 The install-nomake script can be used on any system that does not
432 have make installed.
433 What other modules will I need ?
435 perl-ldap does use other modules. Some are required, but some are
436 optional (i.e. required to use certain features)
437 Convert::ASN1
439 This module is required for perl-ldap to work.
440 You can obtain the latest release from
442 http://search.cpan.org/search?module=Convert::ASN1
443 Authen::SASL
445 This module is optional. You only need to install Authen::SASL if
446 you want to use the SASL authentication method.
447 You can obtain the latest release from
449 http://search.cpan.org/search?module=Authen::SASL
450 Digest::MD5
452 This module is optional. It also requires a C compiler when
453 installing. You only need to install Digest::MD5 if you want to
454 use the SASL DIGEST-MD5 authentication method.
455 You can obtain the latest release from
457 http://search.cpan.org/search?module=Digest::MD5
458 URI::ldap
460 This module is optional. You only need to install URI::ldap if you
461 are going to need to parse ldap referrals. Net::LDAP does not do
462 this automatically yet, so this module is not used by perl-ldap.
463 You can obtain the latest release from
465 http://search.cpan.org/search?module=URI::ldap
466 OpenSSL and IO::Socket::SSL for Net::LDAPS
468 If you want to use Net::LDAP::LDAPS you will need this module and
469 the OpenSSL software package.
470 You can obtain the latest release of IO::Socket::SSL from
472 http://search.cpan.org/search?module=IO::Socket::SSL
473 You can obtain the latest release of OpenSSL from
475 http://www.openssl.org/
476 If you are using a Linux system, many of the distributions have RPM
478 packages that you can install. Use your favorite web search engine
479 to find the package that you need.
480 XML::SAX and XML::SAX::Writer
482 If you want to use Net::LDAP::DSML you will need these modules.
483 You can obtain the latest releases from
485 http://search.cpan.org/search?module=XML::SAX
486 http://search.cpan.org/search?module=XML::SAX::Writer
487 ResourcePool::Factory::Net::LDAP
489 If you want to use failover the ResourcePool::Factory::Net::LDAP
490 perl module provides methods to do this.
491 You can obtain the latest release from
493 http://search.cpan.org/search?module=ResourcePool::Factory::Net::LDAP
494
496 How do I connect to my server ?
497 The connection to the server is created when you create a new Net::LDAP
498 object, e.g.
499 $ldap = Net::LDAP->new($server);
501 Net::LDAP->new sometimes returns undef, why ?
503 The constructor will return undef if there was a problem connecting to
504 the specified server. Any error message will be available in $@
505 What is the proper format of the bind DN.
507 The DN used to bind to a directory is a FULLY QUALIFIED DN. The exact
508 structure of the DN will depend on what data has been stored in the
509 server.
510 The following are valid examples.
512 uid=clif,ou=People,dc=umich,dc=edu
514 cn=directory manager,ou=admins,dc=umich,dc=edu
516 In some servers the following would be a valid fully qualified DN of
518 the directory manager.
519 cn=directory manager
521 How can I tell when the server returns an error, bind() always returns true
523 ?
524 Most methods in Net::LDAP return a Net::LDAP::Message object, or a sub-
525 class of that. This object will hold the results from the server,
526 including the result code.
527 So, for example, to determine the result of the bind operation.
529 $mesg = $ldap->bind( $dn, password => $passwd );
531 if ( $mesg->code ) {
533 # Handle error codes here
534 }
535 How can I set the LDAP version of a connection to my ldap server?
537 This is done by adding the version option when connecting or binding to
538 the LDAP server.
539 For example;
541 $ldap = Net::LDAP->new( $server, version => 3 );
543 or
545 $mesg = $ldap->bind( $dn, password => $passwd, version => 3 );
547 Valid version numbers are 2 and 3. As of perl-ldap 0.27 the default
549 LDAP version is 3.
550 I did a search on my directory using the 'search' method. Where did the
552 results go ?
553 Your search results are stored in a 'search object'. Consider the
554 following:
555 use Net::LDAP;
557 $ldap = Net::LDAP->new('ldap.acme.com') or die "$@";
559 $mesg = $ldap->search(
560 base => "o=acme.com",
561 filter => "uid=jsmith",
562 );
563 $mesg is a search object. It is a reference blessed into the
565 Net::LDAP::Search package. By calling methods on this object you can
566 obtain information about the result and also the individual entries.
567 The first thing to check is if the search was successful. This is done
569 with with the method $mesg->code. This method will return the status
570 code that the server returned. A success will yield a zero value, but
571 there are other values, some of which could also be considered a
572 success. See Net::LDAP::Constant
573 use Net::LDAP::Util qw(ldap_error_text);
575 die ldap_error_text($mesg->code)
577 if $mesg->code;
578 There are two ways in which you can access the entries. You can access
580 then with an index or you can treat the container like a stack and
581 shift each entry in turn. For example
582 # as an array
584 # How many entries were returned from the search
586 my $max = $mesg->count;
587 for( my $index = 0 ; $index < $max ; $index++) {
589 my $entry = $mesg->entry($index);
590 # ...
591 }
592 # or as a stack
594 while( my $entry = $mesg->shift_entry) {
596 # ...
597 }
598 In each case $entry is an entry object. It is a reference blessed into
600 the Net::LDAP::Entry package. By calling methods on this object you can
601 obtain information about the entry.
602 For example, to obtain the DN for the entry
604 $dn = $entry->dn;
606 To obtain the attributes that a given entry has
608 @attrs = $entry->attributes;
610 And to get the list of values for a given attribute
612 @values = $entry->get( 'sn' );
614 And to get the first of the values for a given attribute
616 $values = $entry->get( 'cn' );
618 One thing to remember is that attribute names are case insensitive, so
620 'sn', 'Sn', 'sN' and 'SN' are all the same.
621 So, if you want to print all the values for the attribute 'ou' then
623 this is as simple as
624 foreach ($entry->get_value( 'ou' )) {
626 print $_,"\n";
627 }
628 Now if you just want to print all the values for all the attributes you
630 can do
631 foreach my $attr ($entry->attributes) {
633 foreach my $value ($entry->get_value($attr)) {
634 print $attr, ": ", $value, "\n";
635 }
636 }
637 How do I limit the scope of a directory search.
639 You limit the scope of a directory search by setting the scope
640 parameter of search request. Consider the following:
641 use Net::LDAP;
643 $ldap = Net::LDAP->new('ldap.acme.com') or die "$@";
645 $mesg = $ldap->search(
646 base => "o=acme.com",
647 scope => 'sub',
648 filter => "uid=jsmith",
649 );
650 Values for the scope parameter are as follows.
652 base
654 Search only the base object.
655 one Search the entries immediately below the base object.
657 sub Search the whole tree below the base object. This is the default.
659
661 There are two ways of retrieving the results of a requested LDAP
662 search; inline and by using a callback subroutine.
663 USING THE INLINE APPROACH
665 Using the inline approach involves requesting the data and then waiting
666 for all of the data to be returned before the user starts processing
667 the data.
668 Example:
670 use Net::LDAP;
672 $ldap = Net::LDAP->new('ldap.acme.com') or die "$@";
674 $mesg = $ldap->search(
675 base => "o=acme.com",
676 scope => 'sub',
677 filter => "sn=smith",
678 );
679 #
680 # At this point the user can get the returned data as an array
681 # or as a stack.
682 # In this example we will use an array
683 # How many entries were returned from the search
685 my $max = $mesg->count;
686 for( my $index = 0 ; $index < $max ; $index++)
688 {
689 my $entry = $mesg->entry($index);
690 my $dn = $entry->dn; # Obtain DN of this entry
691 @attrs = $entry->attributes; # Obtain attributes for this entry.
693 foreach my $var (@attrs)
694 {
695 #get a list of values for a given attribute
696 $attr = $entry->get_value( $var, asref => 1 );
697 if ( defined($attr) )
698 {
699 foreach my $value ( @$attr )
700 {
701 print "$var: $value\n"; # Print each value for the attribute.
702 }
703 }
704 }
705 }
706 As you can see the example is straight forward, but there is one
708 drawback to this approach. You must wait until all entries for the
709 request search to be returned before you can process the data. If
710 there several thousand entries that match the search filter this could
711 take quite a long time period.
712 USING THE CALLBACK SUBROUTINE APPROACH
714 Using the callback approach involves requesting the data be sent to a
715 callback subroutine as each entry arrives at the client.
716 A callback is just a subroutine that is passed two parameters when it
718 is called, the mesg and entry objects.
719 Example:
721 use Net::LDAP;
723 $ldap = Net::LDAP->new('ldap.acme.com') or die "$@";
725 $mesg = $ldap->search(
726 base => "o=acme.com",
727 scope => 'sub',
728 filter => "sn=smith",
729 callback => \&callback,
730 );
731 #
732 # At this point the user needs to check the status of the
733 # ldap search.
734 #
735 if ( $mesg->code )
737 {
738 $errstr = $mesg->code;
739 print "Error code: $errstr\n";
740 $errstr = ldap_error_text($errstr);
741 print "$errstr\n";
742 }
743 sub callback
746 {
747 my ( $mesg, $entry) = @_;
748 #
750 # First you must check to see if something was returned.
751 # Last execution of callback subroutine will have no
752 # defined entry and mesg object
753 #
754 if ( !defined($entry) )
755 {
756 print "No records found matching filter $match.\n"
757 if ($mesg->count == 0) ; # if mesg is not defined nothing will print.
758 return;
759 }
760 my $dn = $entry->dn; # Obtain DN of this entry
762 @attrs = $entry->attributes; # Obtain attributes for this entry.
764 foreach my $var (@attrs)
765 {
766 #get a list of values for a given attribute
767 $attr = $entry->get_value( $var, asref => 1 );
768 if ( defined($attr) )
769 {
770 foreach my $value ( @$attr )
771 {
772 print "$var: $value\n"; # Print each value for the attribute.
773 }
774 }
775 }
776 #
777 # For large search requests the following 2 lines of code
778 # may be very important, they will reduce the amount of memory
779 # used by the search results.
780 #
781 # If the user is not worried about memory usage then the 2 lines
782 # of code can be omitted.
783 #
784 $mesg->pop_entry;
785 } # End of callback subroutine
787 As you can see the example is straight forward and it does not waste
789 time waiting for all of the entries to be returned. However if the
790 pop_entry method is not used the callback approach can allocate a lot
791 of memory to the search request.
792
794 Using an SSL network connection, how do I connect to my server?
795 This class is a subclass of Net::LDAP so all the normal Net::LDAP
796 methods can be used with a Net::LDAPS object; see the documentation for
797 Net::LDAP to find out how to query a directory server using the LDAP
798 protocol.
799 The connection to the server is created when you create a new
801 Net::LDAPS object, e.g.
802 $ldaps = Net::LDAPS->new($server,
804 port => '10000',
805 verify => 'require',
806 capath => '/usr/local/cacerts/',
807 );
808 Starting with version 0.28 perl-ldap also supports URIs in the new
810 method. So, the above can also be expressed as:
811 $ldaps = Net::LDAP->new("ldaps://$server",
813 port => '10000',
814 verify => 'require',
815 capath => '/usr/local/cacerts/',
816 );
817 There are additional options to the new method with LDAPS URIs and the
819 LDAPS new method and several additional methods are included in the
820 LDAPS object class.
821 For further information and code examples read the LDAPS module
823 documentation; perldoc Net::LDAPS
824
826 What are LDAP groups.
827 LDAP groups are object classes that contain an attribute that can store
828 multiple DN values. Two standard object classes are 'groupOfNames'
829 (which has a 'member' attribute) and 'groupOfUniqueNames' (which has a
830 'uniqueMember' attribute.)
831 According to the RFCs a group can be a member of another group, but
833 some LDAP server vendors restrict this flexibility by not allowing
834 nested groups in their servers.
835 Two scripts for working with groups are available in the contrib
837 directory. They are isMember.pl and printMembers.pl.
838 How do you format a filter to search for entries whose 'member' attribute
840 has a particular value?
841 Asking for (member=*) is OK - the directory uses the equality matching
842 rule which is defined for the member attribute.
843 Asking for (member=c*) is not OK - there is no defined substring
845 matching rule for the member attribute. That's because the member
846 values are *not* strings, but distinguished names. There is no
847 substring matching rule for DNs, see RFC 2256 section 5.50.
848 What you have to do is get the results of (member=*) and then select
850 the required results from the returned values. You need to do this
851 using knowledge of the string representation of DNs defined in RFC
852 2253, which is important because the same DN can have different string
853 representations. So you need to perform some canonicalization if you
854 want to be correct.
855
857 How can I access DSML features from PERL-LDAP.
858 Directory Service Markup Language (DSML) is the XML standard for
859 representing directory service information in XML.
860 Support for DSML is included in PERL-LDAP starting with version .20.
862 At the moment this module only reads and writes DSML entry entities. It
864 cannot process any schema entities because schema entities are
865 processed differently than elements.
866 Eventually this module will be a full level 2 consumer and producer
868 enabling you to give you full DSML conformance.
869 The specification for DSML is at http://www.oasis-open.org/specs/
871 For further information and code examples read the DSML module
873 documentation; perldoc Net::LDAP::DSML
874
876 How do I access the Control features.
877 Support for LDAP version 3 Control objects is included in perl-ldap
878 starting with version .20.
879 For further information and code examples read the Control module
881 documentation; perldoc Net::LDAP::Control
882 How do I access the Virtual List features.
884 Support for Virtual Lists is included in perl-ldap starting with
885 version .20.
886 For further information and code examples read the Control module
888 documentation; perldoc Net::LDAP::Control
889
891 Are there any other code examples.
892 Yes, there is an Examples pod file. To view the pod do the following
893 command; perldoc Net::LDAP::Examples
894 There is user contributed software in the contrib directory that is
896 supplied with the PERL-LDAP distribution. This is an excellent source
897 of information on how to use the PERL-LDAP module.
898 Are there any performance issues with perl-ldap ?
900 In the vast majority of use cases (one user has suggested 9 out of 10)
901 there are no performance issues with perl-ldap.
902 Where you may wish to use perl-ldap to perform, for example, a very
904 large number of queries (e.g. 10,000) in succession you may find a
905 noticeable performance difference between perl-ldap and non pure-perl
906 modules. This is not because of perl-ldap itself but because of the
907 pure-perl Convert::ASN1 module that it depends on.
908 You should make up your own mind, based upon your own situation
910 (performance requirements, hardware etc.) as to whether you should use
911 perl-ldap or not. The figures quoted in this answer are only
912 indicative, and will differ for different people.
913 Can I contribute perl scripts that use perl-ldap to the contrib section?
915 Any one can submit a perl script that uses perl-ldap for inclusion in
916 the contrib section. Graham Barr will determine if the script will be
917 included and will do the initial check in of the script to the SVN
918 system on http://svn.mutatus.co.uk. Graham will make you the
919 owner/developer of the script.
920 There are a couple of requirements for consideration.
922 You must supply a one line description of your script to be included in
924 the contrib readme file.
925 Inside the script will be the pod documentation for the script. No
927 auxiliary documentation will be allowed. For examples of how to do
928 this see the tklkup script currently in the contrib section.
929 Is it possible to get a complete entry, DN and attributes without
931 specifying the attributes name?
932 Yes, just specify you want a list of no attributes back. The RFC says
933 that this tells the server to return all readable attributes back
934 (there may be access controls to prevent some from being returned.)
935 So in the search method, just set (for LDAPv2):
937 attrs => [ ]
939 If you are using LDAPv3, you can specify an attribute called "*"
941 instead, which lets you ask for additional (i.g. operational)
942 attributes in the same search.
943 attrs => [ "*" ]
945 To get all operational attributes in a search, some servers allow the
947 use of the "+" pseudo attribute. So that with these servers
948 attrs => [ "*", "+" ]
950 will return the most information from the server.
952 How do I put a JPEG photo into a entry in the directory.
954 Follow the following code example, replacing the (...) with whatever is
955 relevant to your setup.
956 use Net::LDAP;
958 use Net::LDAP::Util qw(ldap_error_text);
959 use CGI;
960 local $/ = undef;
962 my $jpeg = <$filename>;
963 my $ldap = Net::LDAP->new(...);
965 my $res = $ldap->bind(...);
966 $res = $ldap->modify(...,
967 add => [ 'jpegPhoto' => [ $jpeg ] ]);
968 $res = $ldap->unbind();
969 How do I add a jpeg photo into a entry in the directory via html-forms.
971 Follow the following code example, replacing the (...) with whatever is
972 relevant to your setup.
973 use Net::LDAP;
975 use Net::LDAP::Util qw(ldap_error_text);
976 use CGI;
977 my $q = new CGI;
979 print $q->header;
981 print $q->start_html(-title => 'Change JPEG photo');
982 if ($q->param('Update')) {
984 my $filename = $q->param('jpeg');
985 local $/ = undef;
986 my $jpeg = <$filename>;
987 my $ldap = Net::LDAP->new(...);
989 my $res = $ldap->bind(...);
990 $res = $ldap->modify(...,
991 add => [ 'jpegPhoto' => [ $jpeg ] ]);
992 $res = $ldap->unbind();
993 } else {
994 print $q->start_multipart_form();
995 print $q->filefield(-name => 'jpeg', -size => 50);
996 print $q->submit('Update');
997 print $q->end_form();
998 }
999 print $q->end_html();
1001 What happens when you delete an attribute that does not exist.
1003 It is an error to delete an attribute that doesn't exist. When you get
1004 the error back the server ignores the entire modify operation you sent
1005 it, so you need to make sure the error doesn't happen.
1006 Another approach, if you are using LDAPv3 (note beginning with version
1008 .27 Net::LDAP uses LDAPv3 by default) is to use a 'replace' with your
1009 attribute name and no values. In LDAPv3, this is defined to always
1010 work even if that attribute doesn't exist in the entry.
1011 i.e.:
1013 my $mesg = $ldap->modify( $entry, replace => { %qv_del_arry } );
1015 But make sure you are using LDAPv3, because that is defined to not work
1017 in LDAPv2. (A nice incompatibility between LDAPv2 and LDAPv3.)
1018 How can I delete a referral from an LDAP tree.
1020 Since this is a proprietary feature, you will have to check your
1021 server's documentation. You might find that you need to use a control.
1022 If there is a control called something like managedsait, that's the one
1023 you should probably use. For proper operation you will need the oid
1024 number for managedsait; 2.16.840.1.113730.3.4.2 and do not specify a
1025 value for type.
1026 The code required will look similar to the following code snippet.
1028 $mesg = $ldap->delete("ref=\"ldap://acme/c=us,o=bricks\",o=clay",
1030 control => {type => "2.16.840.1.113730.3.4.2"} );
1031 How do I add an ACI/ACL entry to a directory server with Perl-LDAP.
1033 ACIs and ACLs are proprietary features in LDAP. The following code
1034 snippet works with a Netscape directory server. You will need the
1035 specify the correct DN (-DN-) and correct attribute(s) (-nom attr-).
1036 my $aci = '(target="ldap:///-DN-")(targetattr="-nom attr-")(version 3.0;
1038 acl "-nom acl-"; deny(all) userdn = "ldap:///self";)' ;
1039 $ldap->modify($dn_modif, add => {'aci' => $aci });
1041 How do I avoid file type and data type mis-matching when loading data from
1043 a Win32 system.
1044 When loading a binary attribute with data read from a file on a Win32
1045 system, it has been noted that you should set "binmode" on the file
1046 before reading the file contents into the data array.
1047 Another possible solution to this problem is to convert the binary data
1049 into a base64 encoded string and then store the encoded string in the
1050 file. Then when reading the file, decode the base64 encoded string
1051 back to binary and then use perl ldap to store the data in the
1052 directory.
1053 How do I create a Microsoft Exchange 5.x user.
1055 This is a solution provide by a perl-ldap user.
1056 This code works with ActiveState Perl running on WinNT 4. Please note
1058 that this requires the Win32::Perms module, and needs valid NT account
1059 info to replace the placeholders.
1060 use Net::LDAP;
1062 use Net::LDAP::Util;
1063 use Win32::Perms;
1064 #Constants taken from ADSI Type Library
1066 $ADS_RIGHT_EXCH_ADD_CHILD = 1;
1067 $ADS_RIGHT_EXCH_DELETE = 0x10000;
1068 $ADS_RIGHT_EXCH_DS_REPLICATION = 64;
1069 $ADS_RIGHT_EXCH_DS_SEARCH = 256;
1070 $ADS_RIGHT_EXCH_MAIL_ADMIN_AS = 32;
1071 $ADS_RIGHT_EXCH_MAIL_RECEIVE_AS = 16;
1072 $ADS_RIGHT_EXCH_MAIL_SEND_AS = 8;
1073 $ADS_RIGHT_EXCH_MODIFY_ADMIN_ATT = 4;
1074 $ADS_RIGHT_EXCH_MODIFY_SEC_ATT = 128;
1075 $ADS_RIGHT_EXCH_MODIFY_USER_ATT = 2;
1076 $EXCH_USER_RIGHTS = $ADS_RIGHT_EXCH_MAIL_RECEIVE_AS |
1078 $ADS_RIGHT_EXCH_MAIL_SEND_AS |
1079 $ADS_RIGHT_EXCH_MODIFY_USER_ATT;
1080 $exch = Net::LDAP->new('server', debug =>0) || die $@;
1082 $exch->bind( 'cn=admin_user,cn=nt_domain,cn=admin', version =>3,
1084 password=>'password');
1085 $myObj = Win32::Perms->new();
1087 $Result = $myObj->Owner('nt_domain\user_name');
1088 $myObj->Group('nt_domain\Everyone');
1089 $myObj->Allow('nt_domain\user_name',
1090 $EXCH_USER_RIGHTS,OBJECT_INHERIT_ACE);
1091 $BinarySD = $myObj->GetSD(SD_RELATIVE);
1092 $TextSD = uc(unpack( "H*", $BinarySD ));
1093 Win32::Perms::ResolveSid('nt_domain\user_name', $sid);
1094 $mysid = uc(unpack("H*",$sid));
1095 $result = $exch->add ( dn =>
1097 'cn=user_name,cn=container,ou=site,o=organization',
1098 attr => [ 'objectClass' => ['organizationalPerson'],
1099 'cn' => 'directory_name',
1100 'uid' => 'mail_nickname',
1101 'mail' => 'smtp_address',
1102 'assoc-nt-account' => [ $mysid ],
1103 'nt-security-descriptor' => [ $TextSD ],
1104 'mailPreferenceOption' => 0
1105 ]
1106 );
1107 print ldap_error_name($result->code);
1110 Ho do I reset a user's password ...
1112 ... in most LDAP servers ?
1113 Most LDAP servers use the standard userPassword attribute as the
1115 attribute to set when you want to change a user's password.
1116 They usually allow to set the password either using the regular modify
1118 operation on the userPassword attribute or using the extended LDAP
1119 Password Modify operation defined in RFC3062.
1120 The recommended method is the extended Password Modify operation, which
1122 offers a standardized way to set user passwords but unfortunately is
1123 not available on all LDAP servers.
1124 Whether the extended Password Modify operation is available can be
1126 found out by searching the attribute supportedExtension for the value
1127 1.3.6.1.4.1.4203.1.11.1 in the RootDSE object.
1128 If the extended Password Modify operation is not available the
1130 alternative is the regular modification of the userPassword attribute.
1131 But this method has some drawbacks:
1133 · Depending on the type of the server the arguments to the modify
1135 operations may vary. Some want the modify done with replace, some
1136 want it done by explicitly deleting the old password and add of the
1137 new one. This may even depend on whether you change the password
1138 for the bound user or as an administrator for another user.
1139 · With the modify operation some servers expect the client to do the
1141 hashing of the password on the client side. I.e. all clients that
1142 set passwords need to agree on the algorithm and the format of the
1143 hashed password.
1144 · Some LDAP servers do not allow setting the password if the
1146 connection is not sufficiently secured. I.e. require SSL or TLS
1147 support to set the password (which is heavily recommended anyway
1148 ;-)
1149 Here is an example of how to change your own password (for brevity's
1151 sake error checking is left out):
1152 use Net::LDAP;
1154 my $ldap = Net::LDAP->new('ldaps://server.domain') or die "$@";
1156 my $mesg = $ldap->bind('cn=Joe User,dc=perl,dc=ldap,dc=org',
1157 password => 'oldPW');
1158 my $rootdse = $ldap->root_dse();
1160 if ($rootdse->supported_extension('1.3.6.1.4.1.4203.1.11.1') {
1162 require Net::LDAP::Extension::SetPassword;
1164 $mesg = $ldap->set_password(user => 'cn=Joe User,dc=perl,dc=ldap,dc=org',
1166 oldpasswd => 'oldPW',
1167 newpasswd => 'newPW');
1168 }
1169 else {
1170 $mesg = $ldap->modify('cn=Joe User,dc=perl,dc=ldap,dc=org',
1171 changes => [
1172 delete => [ userPassword => $oldPW ]
1173 add => [ userPassword => $newPW ] ]);
1174 }
1175 $ldap->unbind();
1177 ... in MS Active Directory ?
1179 With Active Directory a user's password is stored in the unicodePwd
1181 attribute and changed using the regular modify operation.
1182 ADS expects this password to be encoded in Unicode - UTF-16 to be
1184 exact. Before the unicode conversion is done the password needs to be
1185 surrounded by double quotes which do not belong to the user's password.
1186 For the password modify operation to succeed SSL is required.
1188 When changing the password for the user bound to the directory ADS
1190 expects it to be done by deleting the old password and adding the new
1191 one. When doing it as a user with administrative privileges replacing
1192 the unicodePwd's value with a new one is allowed too.
1193 Here's an example that demonstrates setting your own password (again
1195 almost no error checking):
1196 use Net::LDAP;
1198 use Unicode::Map8;
1199 use Unicode::String qw(utf16);
1200 # build the conversion map from your local character set to Unicode
1202 my $charmap = Unicode::Map8->new('latin1') or die;
1203 # surround the PW with double quotes and convert it to UTF-16
1205 # byteswap() was necessary in experiments on i386 Linux, YMMV
1206 my $oldUniPW = $charmap->tou('"'.$oldPW.'"')->byteswap()->utf16();
1207 my $newUniPW = $charmap->tou('"'.$newPW.'"')->byteswap()->utf16();
1208 my $ldap = Net::LDAP->new('ldaps://ads.domain.controller') or die "$@";
1210 my $mesg = $ldap->bind('cn=Joe User,dc=your,dc=ads,dc=domain',
1212 password => 'oldPW');
1213 $mesg = $ldap->modify('cn=Joe User,dc=your,dc=ads,dc=domain',
1215 changes => [
1216 delete => [ unicodePwd => $oldUniPW ]
1217 add => [ unicodePwd => $newUniPW ] ]);
1218 $ldap->unbind();
1220 How can I simulate server failover.
1222 Perl-LDAP does not do server failover, however there are several
1223 programming options for getting around this situation.
1224 Here is one possible solution.
1226 unless ( $ldaps =
1228 Net::LDAPS->new($ldapserverone,
1229 port=>636,timeout=>5) )
1230 {
1231 $ldaps = Net::LDAPS->new($ldapservertwo,
1232 port=>636,timeout=>20) ||
1233 return
1234 "Can't connect to $ldapserverone or $ldapservertwo via LDAPS: $@";
1235 }
1236 As of version 0.27 of perl-ldap the above can be expressed much
1238 simpler:
1239 $ldaps = Net::LDAPS->new([ $ldapserverone, $ldapservertwo ],
1241 port=>636, timeout=>5) or die "$@";
1242
1244 How do I store X.509 certificates in the directory?
1245 The first problem here is that there are many different formats to hold
1246 certificates in, for example PEM, DER, PKCS#7 and PKCS#12. The
1247 directory only uses the DER format (more correctly, it only uses the
1248 BER format) which is a binary format.
1249 Your first job is to ensure that your certificates are therefore in
1251 DER/BER format. You could use OpenSSL to convert from PEM like this:
1252 openssl x509 -inform PEM -in cert.pem -outform DER -out cert.der
1254 Consult the OpenSSL documentation to find out how to perform other
1256 conversions.
1257 To add a certificate to the directory, just slurp in the DER/BER
1259 certificate into a scalar variable, and add it to the entry's
1260 userCertificate attribute. How you do that will depend on which version
1261 of LDAP you are using.
1262 To slurp in the certificate try something like this:
1264 my $cert;
1266 {
1267 local $/ = undef; # Slurp mode
1268 open CERT, "cert.der" or die;
1269 binmode CERT;
1270 $cert = <CERT>;
1271 close CERT;
1272 }
1273 # The certificate is now in $cert
1274 For LDAPv2, because most directory vendors ignore the string
1276 representation of certificates defined in RFC 1778, you should add this
1277 value to the directory like this:
1278 $res = $ldap->modify("cn=My User, o=My Company,c=XY",
1280 add => [
1281 'userCertificate' => [ $cert ]
1282 ]);
1283 die "Modify failed (" . ldap_error_name($res->code) . ")\n"
1284 if $res->code;
1285 For LDAPv3, you must do this instead:
1287 $res = $ldap->modify("cn=My User, o=My Company, c=XY",
1289 add => [
1290 'userCertificate;binary' => [ $cert ]
1291 ]);
1292 die "Modify failed (" . ldap_error_name($res->code) . ")\n"
1293 if $res->code;
1294 Of course, the entry you are trying to add the certificate to must use
1296 object classes that permit the userCertificate attribute, otherwise the
1297 modify will fail with an object class violation error. The
1298 inetOrgPerson structural object class permits userCertificates, as does
1299 the strongAuthenticationUser auxiliary object class. Others might also.
1300
1302 URLs.
1303 Directory Services Mark Language (DSML)
1304 http://www.oasis-open.org/specs/
1305 eMailman LDAP information http://www.emailman.com/ldap/
1307 Rafael Corvalan's LDAP shell http://sf.net/projects/ldapsh
1309 LDAPS, also known as LDAPGURU. This web site has a nasty habit of
1311 resizing the browser to cover the WHOLE screen. http://www.ldaps.com
1312 Jeff Hodges's Kings Mountain LDAP
1314 http://www.kingsmountain.com/ldapRoadmap.shtml
1315 Mark Wahl's LDAP World at Innosoft. http://www.innosoft.com/ldapworld/
1317 (outdated: last update was in 1998)
1318 Open Source LDAP Directory Server. http://www.openldap.org/
1320 CriticalPath http://www.cp.net/
1322 IBM Directory Server
1324 http://www-306.ibm.com/software/network/directory/server/
1325 Innosoft http://www.innosoft.com (acquired by Sun)
1327 Isode (was MessagingDirect) http://www.isode.com/
1329 Netscape Directory Developers Area
1331 http://developer.netscape.com/directory/
1332 Nexor's X.500 and Internet Directories
1334 http://www.nexor.com/info/directory.htm/
1335 Novell's eDirectory http://www.novell.com/
1337 Novell's LDAPzone http://ldapzone.com/
1339 Octet String http://www.octetstring.com/
1341 SUN JAVA JNDI (Java Naming and Directory Interface)
1343 http://www.java.sun.com/jndi/
1344 Sun One, formerly Iplanet. http://wwws.sun.com/software/
1346 Eine deutsche LDAP Website A German LDAP Website
1348 http://verzeichnisdienst.de/ldap/Perl/index.html
1349 The 2 following URLs deal mainly with Microsoft's Active Directory.
1351 Directory Works http://directoryworks.com/
1353 ActiveX LDAP Client http://www.polonia-online.com/ldap/
1355 BOOKS
1357 Developing LDAP and ADSI Clients for Microsoft(R) Exchange. By Sven B.
1358 Schreiber. ISBN: 0201657775
1359 Implementing LDAP. By Mark Wilcox. ISBN: 1861002211
1361 LDAP: Programming Directory-Enabled Applications With Lightweight
1363 Directory Access Protocol. By Tim Howes, Mark Smith. ISBN:
1364 1578700000
1365 LDAP Programming; Directory Management and Integration. By Clayton
1367 Donley. ISBN: 1884777910
1368 LDAP Programming with Java. By Rob Weltman, Tony Dahbura. ISBN:
1370 0201657589
1371 LDAP System Administration. By Gerald Carter. ISBN: 1565924916
1373 Managing Enterprise Active Directory Services. By Robbie Allen,
1375 Richard Puckett. ISBN: 0672321254
1376 Solaris and LDAP Naming Services. By Tom Bialaski, Michael Haines.
1378 ISBN: 0-13-030678-9
1379 Understanding and Deploying LDAP Directory Services (2ed). By Tim
1381 Howes, Mark Smith, Gordon Good. ISBN: 0672323168
1382 LDAP Directories Explained. By Brian Arkills. ISBN 0-201-78792-X
1384
1386 Any good FAQ is made up of many authors, everyone that contributes
1387 information to the perl-ldap mail list is a potential author.
1388 An attempt to maintain this FAQ is being done by Chris Ridd
1390 <chris.ridd@isode.com> and Peter Marschall <peter@adpm.de>. It was
1391 previously updated by Clif Harden <charden@pobox.com>.
1392 The original author of this FAQ was Graham Barr <gbarr@pobox.com>
1394 Please report any bugs, or post any suggestions, to the perl-ldap
1396 mailing list <perl-ldap@perl.org>.
1397
1399 Copyright (c) 1999-2004 Graham Barr. All rights reserved. This document
1400 is distributed, and may be redistributed, under the same terms as Perl
1401 itself.
1402perl v5.10.1 2017-03-21 Net::LDAP::FAQ(3)