# $OpenLDAP$
-# Copyright 2007-2008 The OpenLDAP Foundation, All Rights Reserved.
+# Copyright 2007-2013 The OpenLDAP Foundation, All Rights Reserved.
# COPYING RESTRICTIONS APPLY, see COPYRIGHT.
H1: Overlays
Overlays may be compiled statically into {{slapd}}, or when module support
is enabled, they may be dynamically loaded. Most of the overlays
-are only allowed to be configured on individual databases, but some
-may also be configured globally.
+are only allowed to be configured on individual databases.
-Essentially, they represent a means to:
+Some can be stacked on the {{EX:frontend}} as well, for global use. This means that
+they can be executed after a request is parsed and validated, but right before the
+appropriate database is selected. The main purpose is to affect operations
+regardless of the database they will be handled by, and, in some cases,
+to influence the selection of the database by massaging the request DN.
+
+Essentially, overlays represent a means to:
* customize the behavior of existing backends without changing the backend
code and without requiring one to write a new custom backend with
* write functionality of general usefulness that can be applied to
different backend types
+When using {{slapd.conf}}(5), overlays that are configured before any other
+databases are considered global, as mentioned above. In fact they are implicitly
+stacked on top of the {{EX:frontend}} database. They can also be explicitly
+configured as such:
+
+> database frontend
+> overlay <overlay name>
+
Overlays are usually documented by separate specific man pages in section 5;
the naming convention is
> servers/slapd/overlays/
That directory also contains the file slapover.txt, which describes the
-rationale of the overlay implementation, and may serve as guideline for the
+rationale of the overlay implementation, and may serve as a guideline for the
development of custom overlays.
Contribware overlays are located in
along with other types of run-time loadable components; they are officially
distributed, but not maintained by the project.
-They can be stacked on the frontend as well; this means that they can be
-executed after a request is parsed and validated, but right before the
-appropriate database is selected. The main purpose is to affect operations
-regardless of the database they will be handled by, and, in some cases,
-to influence the selection of the database by massaging the request DN.
-
-All the current overlays in 2.4 are listed and described in detail in the
+All the current overlays in OpenLDAP are listed and described in detail in the
following sections.
> # numResponses: 3
> # numEntries: 2
-For more information, please see {{slapo-accesslog(5)}} and the {{SECT:delta-syncrepl replication}} section.
+
+H3: Further Information
+
+{{slapo-accesslog(5)}} and the {{SECT:delta-syncrepl replication}} section.
H2: Audit Logging
In this example for testing, we are logging changes to {{F:/tmp/auditlog.ldif}}
-A typical {{TERM:LDIF}} file created by {{B:slapo-auditlog (5)}} would look like:
+A typical {{TERM:LDIF}} file created by {{B:slapo-auditlog(5)}} would look like:
> # add 1196797576 dc=suretecsystems,dc=com cn=admin,dc=suretecsystems,dc=com
> dn: dc=suretecsystems,dc=com
> # end add 1196797577
+H3: Further Information
+
+{{:slapo-auditlog(5)}}
+
+
H2: Chaining
In order to demonstrate how this overlay works, we shall discuss a typical
scenario which might be one master server and three Syncrepl slaves.
-On each replica, add this near the top of the file (global), before any database
-definitions:
+On each replica, add this near the top of the {{slapd.conf}}(5) file
+(global), before any database definitions:
> overlay chain
> chain-uri "ldap://ldapmaster.example.com"
bound to the slave will also exist on the master. If that DN does not have
update privileges on the master, nothing will happen.
-You will need to restart the slave after these changes. Then, if you are using
-{{loglevel stats}} (256), you can monitor an {{ldapmodify}} on the slave and the master.
+You will need to restart the slave after these {{slapd.conf}} changes.
+Then, if you are using {{loglevel stats}} (256), you can monitor an
+{{ldapmodify}} on the slave and the master. (If you're using {{cn=config}}
+no restart is required.)
Now start an {{ldapmodify}} on the slave and watch the logs. You should expect
something like:
> chain-return-error TRUE
+H3: Read-Back of Chained Modifications
+
+Occasionally, applications want to read back the data that they just wrote.
+If a modification requested to a shadow server was silently chained to its
+provider, an immediate read could result in receiving data not yet synchronized.
+In those cases, clients should use the {{B:dontusecopy}} control to ensure
+they are directed to the authoritative source for that piece of data.
+
+This control usually causes a referral to the actual source of the data
+to be returned. However, when the {{slapo-chain(5)}} overlay is used,
+it intercepts the referral being returned in response to the
+{{B:dontusecopy}} control, and tries to fetch the requested data.
+
+
+H3: Further Information
+
+{{:slapo-chain(5)}}
+
+
H2: Constraints
Configuration via {{slapd.conf}}(5) would look like:
> overlay constraint
-> constraint_attribute mail regex ^[:alnum:]+@mydomain.com$
+> constraint_attribute mail regex ^[[:alnum:]]+@mydomain.com$
> constraint_attribute title uri
> ldap:///dc=catalog,dc=example,dc=com?title?sub?(objectClass=titleCatalog)
> objectClass: olcOverlayConfig
> objectClass: olcConstraintConfig
> olcOverlay: constraint
-> olcConstraintAttribute: mail regex ^[:alnum:]+@mydomain.com$
+> olcConstraintAttribute: mail regex ^[[:alnum:]]+@mydomain.com$
> olcConstraintAttribute: title uri ldap:///dc=catalog,dc=example,dc=com?title?sub?(objectClass=titleCatalog)
+
+H3: Further Information
+
+{{:slapo-constraint(5)}}
+
H2: Dynamic Directory Services
Any user can join the meeting, but not add another attendee, but they can refresh the meeting. The ACLs above are quite straight forward to understand.
+
+H3: Further Information
+
+{{:slapo-dds(5)}}
+
+
H2: Dynamic Groups
expands to all user's emails according to our LDAP filter:
In {{slapd.conf}}(5):
+
> overlay dynlist
> dynlist-attrset nisMailAlias labeledURI
retrieved, the search specified in the {{F:labeledURI}} attribute is performed.
Let's say we have this entry in our directory:
+
> cn=all,ou=aliases,dc=example,dc=com
> cn: all
> objectClass: nisMailAlias
directory.
In {{F:slapd.conf}}(5):
+
+> include /path/to/dyngroup.schema
+> ...
> overlay dynlist
-> dynlist-attrset groupOfNames labeledURI member
+> dynlist-attrset groupOfURLs labeledURI member
++
++Note: We must include the {{F:dyngroup.schema}} file that defines the
++{{F:groupOfURLs}} objectClass used in this example.
Let's apply it to the following entry:
+
> cn=allusers,ou=group,dc=example,dc=com
> cn: all
-> objectClass: groupOfNames
+> objectClass: groupOfURLs
> labeledURI: ldap:///ou=people,dc=example,dc=com??one?(objectClass=inetOrgPerson)
The behavior is similar to the dynamic list configuration we had before:
-whenever an entry with the {{F:groupOfNames}} object class is retrieved, the
+whenever an entry with the {{F:groupOfURLs}} object class is retrieved, the
search specified in the {{F:labeledURI}} attribute is performed. But this time,
only the distinguished names of the results are added, and as values of the
{{F:member}} attribute.
object class can hold only names, not DNs, and is therefore not suitable for
dynamic groups.
+
+H3: Further Information
+
+{{:slapo-dynlist(5)}}
+
+
H2: Reverse Group Membership Maintenance
H3: Overview
> include /usr/share/openldap/schema/core.schema
> include /usr/share/openldap/schema/cosine.schema
-> modulepath /usr/lib/openldap
-> moduleload memberof.la
+>
> authz-regexp "gidNumber=0\\\+uidNumber=0,cn=peercred,cn=external,cn=auth"
> "cn=Manager,dc=example,dc=com"
> database bdb
requested explicitly.
+H3: Further Information
+
+{{:slapo-memberof(5)}}
+
+
H2: The Proxy Cache Engine
{{TERM:LDAP}} servers typically hold one or more subtrees of a
H3: Proxy Cache Configuration
The cache configuration specific directives described below must
-appear after a {{EX:overlay proxycache}} directive within a
-{{EX:"database meta"}} or {{EX:database ldap}} section of
+appear after a {{EX:overlay pcache}} directive within a
+{{EX:"database meta"}} or {{EX:"database ldap"}} section of
the server's {{slapd.conf}}(5) file.
H4: Setting cache parameters
-> p
roxyCache <DB> <maxentries> <nattrsets> <entrylimit> <period>
+> p
cache <DB> <maxentries> <nattrsets> <entrylimit> <period>
This directive enables proxy caching and sets general cache
parameters. The <DB> parameter specifies which underlying database
{{EX:bdb}} or {{EX:hdb}}. The <maxentries> parameter specifies the
total number of entries which may be held in the cache. The
<nattrsets> parameter specifies the total number of attribute sets
-(as specified by the {{EX:proxyAttrSet}} directive) that may be
+(as specified by the {{EX:pcacheAttrset}} directive) that may be
defined. The <entrylimit> parameter specifies the maximum number of
entries in a cacheable query. The <period> specifies the consistency
check period (in seconds). In each period, queries with expired
H4: Defining attribute sets
-> p
roxyAttrset <index> <attrs...>
+> p
cacheAttrset <index> <attrs...>
Used to associate a set of attributes to an index. Each attribute
set is associated with an index number from 0 to <numattrsets>-1.
-These indices are used by the proxyTemplate directive to define
+These indices are used by the pcacheTemplate directive to define
cacheable templates.
H4: Specifying cacheable templates
-> p
roxyTemplate <prototype_string> <attrset_index> <TTL>
+> p
cacheTemplate <prototype_string> <attrset_index> <TTL>
Specifies a cacheable template and the "time to live" (in sec) <TTL>
for queries belonging to the template. A template is described by
by <attrset_index>.
-H4: Example
+H4: Example for slapd.conf
An example {{slapd.conf}}(5) database section for a caching server
which proxies for the {{EX:"dc=example,dc=com"}} subtree held
> suffix "dc=example,dc=com"
> rootdn "dc=example,dc=com"
> uri ldap://ldap.example.com/
-> overlay proxycache
-> proxycache bdb 100000 1 1000 100
-> proxyAttrset 0 mail postaladdress telephonenumber
-> proxyTemplate (sn=) 0 3600
-> proxyTemplate (&(sn=)(givenName=)) 0 3600
-> proxyTemplate (&(departmentNumber=)(secretary=*)) 0 3600
+> overlay pcache
+> pcache hdb 100000 1 1000 100
+> pcacheAttrset 0 mail postaladdress telephonenumber
+> pcacheTemplate (sn=) 0 3600
+> pcacheTemplate (&(sn=)(givenName=)) 0 3600
+> pcacheTemplate (&(departmentNumber=)(secretary=*)) 0 3600
>
> cachesize 20
> directory ./testrun/db.2.a
> index objectClass eq
> index cn,sn,uid,mail pres,eq,sub
+H4: Example for slapd-config
+
+The same example as a LDIF file for back-config for a caching server
+which proxies for the {{EX:"dc=example,dc=com"}} subtree held
+at server {{EX:ldap.example.com}}.
+
+> dn: olcDatabase={2}ldap,cn=config
+> objectClass: olcDatabaseConfig
+> objectClass: olcLDAPConfig
+> olcDatabase: {2}ldap
+> olcSuffix: dc=example,dc=com
+> olcRootDN: dc=example,dc=com
+> olcDbURI: "ldap://ldap.example.com"
+>
+> dn: olcOverlay={0}pcache,olcDatabase={2}ldap,cn=config
+> objectClass: olcOverlayConfig
+> objectClass: olcPcacheConfig
+> olcOverlay: {0}pcache
+> olcPcache: hdb 100000 1 1000 100
+> olcPcacheAttrset: 0 mail postalAddress telephoneNumber
+> olcPcacheTemplate: "(sn=)" 0 3600 0 0 0
+> olcPcacheTemplate: "(&(sn=)(givenName=))" 0 3600 0 0 0
+> olcPcacheTemplate: "(&(departmentNumber=)(secretary=))" 0 3600
+>
+> dn: olcDatabase={0}hdb,olcOverlay={0}pcache,olcDatabase={2}ldap,cn=config
+> objectClass: olcHdbConfig
+> objectClass: olcPcacheDatabase
+> olcDatabase: {0}hdb
+> olcDbDirectory: ./testrun/db.2.a
+> olcDbCacheSize: 20
+> olcDbIndex: objectClass eq
+> olcDbIndex: cn,sn,uid,mail pres,eq,sub
+
H5: Cacheable Queries
A LDAP search query is cacheable when its filter matches one of the
-templates as defined in the "proxyTemplate" statements and when it references
+templates as defined in the "pcacheTemplate" statements and when it references
only the attributes specified in the corresponding attribute set.
In the example above the attribute set number 0 defines that only the
attributes: {{EX:mail postaladdress telephonenumber}} are cached for the following
-proxyTemplates.
+pcacheTemplates.
H5: Examples:
> Attrs: mail telephoneNumber
is cacheable, because it matches the template {{EX:(&(sn=)(givenName=))}} and its
- attributes are contained in proxyAttrset 0.
+ attributes are contained in pcacheAttrset 0.
> Filter: (&(sn=Richard*)(telephoneNumber))
> Attrs: givenName
is not cacheable, because the filter does not match the template ( logical
OR "|" condition instead of logical AND "&" )
+
+
+H3: Further Information
+
+{{:slapo-pcache(5)}}
H2: Password Policies
H3: Overview
-This overlay provides a variety of password control mechanisms,
-e.g. password aging, password reuse and duplication control, mandatory
-password resets, etc.
+This overlay follows the specifications contained in the draft RFC titled
+draft-behera-ldap-password-policy-09. While the draft itself is expired, it has
+been implemented in several directory servers, including slapd. Nonetheless,
+it is important to note that it is a draft, meaning that it is subject to change
+and is a work-in-progress.
+
+The key abilities of the password policy overlay are as follows:
+
+* Enforce a minimum length for new passwords
+* Make sure passwords are not changed too frequently
+* Cause passwords to expire, provide warnings before they need to be changed, and allow a fixed number of 'grace' logins to allow them to be changed after they have expired
+* Maintain a history of passwords to prevent password re-use
+* Prevent password guessing by locking a password for a specified period of time after repeated authentication failures
+* Force a password to be changed at the next authentication
+* Set an administrative lock on an account
+* Support multiple password policies on a default or a per-object basis.
+* Perform arbitrary quality checks using an external loadable module. This is a non-standard extension of the draft RFC.
H3: Password Policy Configuration
+Instantiate the module in the database where it will be used, after adding the
+new ppolicy schema and loading the ppolicy module. The following example shows
+the ppolicy module being added to the database that handles the naming
+context "dc=example,dc=com". In this example we are also specifying the DN of
+a policy object to use if none other is specified in a user's object.
+
+> database bdb
+> suffix "dc=example,dc=com"
+> [...additional database configuration directives go here...]
+>
+> overlay ppolicy
+> ppolicy_default "cn=default,ou=policies,dc=example,dc=com"
+
+
+Now we need a container for the policy objects. In our example the password
+policy objects are going to be placed in a section of the tree called
+"ou=policies,dc=example,dc=com":
+
+> dn: ou=policies,dc=example,dc=com
+> objectClass: organizationalUnit
+> objectClass: top
+> ou: policies
+
+
+The default policy object that we are creating defines the following policies:
+
+* The user is allowed to change his own password. Note that the directory ACLs for this attribute can also affect this ability (pwdAllowUserChange: TRUE).
+* The name of the password attribute is "userPassword" (pwdAttribute: userPassword). Note that this is the only value that is accepted by OpenLDAP for this attribute.
+* The server will check the syntax of the password. If the server is unable to check the syntax (i.e., it was hashed or otherwise encoded by the client) it will return an error refusing the password (pwdCheckQuality: 2).
+* When a client includes the Password Policy Request control with a bind request, the server will respond with a password expiration warning if it is going to expire in ten minutes or less (pwdExpireWarning: 600). The warnings themselves are returned in a Password Policy Response control.
+* When the password for a DN has expired, the server will allow five additional "grace" logins (pwdGraceAuthNLimit: 5).
+* The server will maintain a history of the last five passwords that were used for a DN (pwdInHistory: 5).
+* The server will lock the account after the maximum number of failed bind attempts has been exceeded (pwdLockout: TRUE).
+* When the server has locked an account, the server will keep it locked until an administrator unlocks it (pwdLockoutDuration: 0)
+* The server will reset its failed bind count after a period of 30 seconds.
+* Passwords will not expire (pwdMaxAge: 0).
+* Passwords can be changed as often as desired (pwdMinAge: 0).
+* Passwords must be at least 5 characters in length (pwdMinLength: 5).
+* The password does not need to be changed at the first bind or when the administrator has reset the password (pwdMustChange: FALSE)
+* The current password does not need to be included with password change requests (pwdSafeModify: FALSE)
+* The server will only allow five failed binds in a row for a particular DN (pwdMaxFailure: 5).
+
+
+The actual policy would be:
+
+> dn: cn=default,ou=policies,dc=example,dc=com
+> cn: default
+> objectClass: pwdPolicy
+> objectClass: person
+> objectClass: top
+> pwdAllowUserChange: TRUE
+> pwdAttribute: userPassword
+> pwdCheckQuality: 2
+> pwdExpireWarning: 600
+> pwdFailureCountInterval: 30
+> pwdGraceAuthNLimit: 5
+> pwdInHistory: 5
+> pwdLockout: TRUE
+> pwdLockoutDuration: 0
+> pwdMaxAge: 0
+> pwdMaxFailure: 5
+> pwdMinAge: 0
+> pwdMinLength: 5
+> pwdMustChange: FALSE
+> pwdSafeModify: FALSE
+> sn: dummy value
+
+You can create additional policy objects as needed.
+
+
+There are two ways password policy can be applied to individual objects:
+
+1. The pwdPolicySubentry in a user's object - If a user's object has a
+pwdPolicySubEntry attribute specifying the DN of a policy object, then
+the policy defined by that object is applied.
+
+2. Default password policy - If there is no specific pwdPolicySubentry set
+for an object, and the password policy module was configured with the DN of a
+default policy object and if that object exists, then the policy defined in
+that object is applied.
+
+Please see {{slapo-ppolicy(5)}} for complete explanations of features and discussion of
+ "Password Management Issues" at {{URL:http://www.symas.com/blog/?page_id=66}}
+
+
+H3: Further Information
+
+{{:slapo-ppolicy(5)}}
+
H2: Referential Integrity
H3: Referential Integrity Configuration
The configuration for this overlay is as follows:
+
> overlay refint
> refint_attributes <attribute [attribute ...]>
> refint_nothing <string>
To illustrate this overlay, we will use the group membership scenario.
In {{F:slapd.conf}}:
+
> overlay refint
> refint_attributes member
> refint_nothing "cn=admin,dc=example,dc=com"
would be a single member in the group: {{F:cn=admin,dc=example,dc=com}}. This is the
{{F:refint_nothing}} parameter kicking into action so that the schema is not violated.
+The {{rootdn}} must be set for the database as refint runs as the {{rootdn}} to gain access to
+make its updates. The {{rootpw}} does not need to be set.
+
+H3: Further Information
+
+{{:slapo-refint(5)}}
+
+
H2: Return Code
H3: Overview
This overlay is useful to test the behavior of clients when
-server-generated erroneous and/or unusual responses occur.
+server-generated erroneous and/or unusual responses occur,
+for example; error codes, referrals, excessive response times and so on.
+
+This would be classed as a debugging tool whilst developing client software
+or additional Overlays.
+
+For detailed information, please see the {{slapo-retcode(5)}} man page.
H3: Return Code Configuration
+The retcode overlay utilizes the "return code" schema described in the man page.
+This schema is specifically designed for use with this overlay and is not intended
+to be used otherwise.
+
+Note: The necessary schema is loaded automatically by the overlay.
+
+An example configuration might be:
+
+> overlay retcode
+> retcode-parent "ou=RetCodes,dc=example,dc=com"
+> include ./retcode.conf
+>
+> retcode-item "cn=Unsolicited" 0x00 unsolicited="0"
+> retcode-item "cn=Notice of Disconnect" 0x00 unsolicited="1.3.6.1.4.1.1466.20036"
+> retcode-item "cn=Pre-disconnect" 0x34 flags="pre-disconnect"
+> retcode-item "cn=Post-disconnect" 0x34 flags="post-disconnect"
+
+Note: {{retcode.conf}} can be found in the openldap source at: {{F:tests/data/retcode.conf}}
+
+An excerpt of a {{F:retcode.conf}} would be something like:
+
+> retcode-item "cn=success" 0x00
+>
+> retcode-item "cn=success w/ delay" 0x00 sleeptime=2
+>
+> retcode-item "cn=operationsError" 0x01
+> retcode-item "cn=protocolError" 0x02
+> retcode-item "cn=timeLimitExceeded" 0x03 op=search
+> retcode-item "cn=sizeLimitExceeded" 0x04 op=search
+> retcode-item "cn=compareFalse" 0x05 op=compare
+> retcode-item "cn=compareTrue" 0x06 op=compare
+> retcode-item "cn=authMethodNotSupported" 0x07
+> retcode-item "cn=strongAuthNotSupported" 0x07 text="same as authMethodNotSupported"
+> retcode-item "cn=strongAuthRequired" 0x08
+> retcode-item "cn=strongerAuthRequired" 0x08 text="same as strongAuthRequired"
+
+Please see {{F:tests/data/retcode.conf}} for a complete {{F:retcode.conf}}
+
+
+H3: Further Information
+
+{{:slapo-retcode(5)}}
+
H2: Rewrite/Remap
H3: Overview
-It performs basic DN/data rewrite and
-objectClass/attributeType mapping.
+It performs basic DN/data rewrite and objectClass/attributeType mapping. Its
+usage is mostly intended to provide virtual views of existing data either
+remotely, in conjunction with the proxy backend described in {{slapd-ldap(5)}},
+or locally, in conjunction with the relay backend described in {{slapd-relay(5)}}.
+
+This overlay is extremely configurable and advanced, therefore recommended
+reading is the {{slapo-rwm(5)}} man page.
H3: Rewrite/Remap Configuration
+H3: Further Information
+
+{{:slapo-rwm(5)}}
+
+
H2: Sync Provider
H3: Overview
-This overlay implements the provider-side support for syncrepl
-replication, including persistent search functionality
-
+This overlay implements the provider-side support for the LDAP Content Synchronization
+({{REF:RFC4533}}) as well as syncrepl replication support, including persistent search functionality.
H3: Sync Provider Configuration
+There is very little configuration needed for this overlay, in fact for many situations merely loading
+the overlay will suffice.
+
+However, because the overlay creates a contextCSN attribute in the root entry of the database which is
+updated for every write operation performed against the database and only updated in memory, it is
+recommended to configure a checkpoint so that the contextCSN is written into the underlying database to
+minimize recovery time after an unclean shutdown:
+
+> overlay syncprov
+> syncprov-checkpoint 100 10
+
+For every 100 operations or 10 minutes, which ever is sooner, the contextCSN will be checkpointed.
+
+The four configuration directives available are {{B:syncprov-checkpoint}}, {{B:syncprov-sessionlog}},
+{{B:syncprov-nopresent}} and {{B:syncprov-reloadhint}} which are covered in the man page discussing
+various other scenarios where this overlay can be used.
+
+H3: Further Information
+
+The {{:slapo-syncprov(5)}} man page and the {{SECT:Configuring the different replication types}} section
+
H2: Translucent Proxy
H3: Overview
-This overlay can be used with a backend database such as slapd-bdb (5)
+This overlay can be used with a backend database such as {{:slapd-bdb}}(5)
to create a "translucent proxy".
-Content of entries retrieved from a remote LDAP server can be partially
-overridden by the database.
+Entries retrieved from a remote LDAP server may have some or all attributes
+overridden, or new attributes added, by entries in the local database before
+being presented to the client.
+
+A search operation is first populated with entries from the remote LDAP server,
+the attributes of which are then overridden with any attributes defined in the
+local database. Local overrides may be populated with the add, modify, and
+modrdn operations, the use of which is restricted to the root user of the
+translucent local database.
+
+A compare operation will perform a comparison with attributes defined in the
+local database record (if any) before any comparison is made with data in the
+remote database.
H3: Translucent Proxy Configuration
+There are various options available with this overlay, but for this example we
+will demonstrate adding new attributes to a remote entry and also searching
+against these newly added local attributes. For more information about overriding remote
+entries and search configuration, please see {{:slapo-translucent(5)}}
+
+Note: The Translucent Proxy overlay will disable schema checking in the local
+database, so that an entry consisting of overlay attributes need not adhere
+ to the complete schema.
+
+First we configure the overlay in the normal manner:
+
+> include /usr/local/etc/openldap/schema/core.schema
+> include /usr/local/etc/openldap/schema/cosine.schema
+> include /usr/local/etc/openldap/schema/nis.schema
+> include /usr/local/etc/openldap/schema/inetorgperson.schema
+>
+> pidfile ./slapd.pid
+> argsfile ./slapd.args
+>
+> database bdb
+> suffix "dc=suretecsystems,dc=com"
+> rootdn "cn=trans,dc=suretecsystems,dc=com"
+> rootpw secret
+> directory ./openldap-data
+>
+> index objectClass eq
+>
+> overlay translucent
+> translucent_local carLicense
+>
+> uri ldap://192.168.X.X:389
+> lastmod off
+> acl-bind binddn="cn=admin,dc=suretecsystems,dc=com" credentials="blahblah"
+
+You will notice the overlay directive and a directive to say what attribute we
+want to be able to search against in the local database. We must also load the
+ldap backend which will connect to the remote directory server.
+
+Now we take an example LDAP group:
+
+> # itsupport, Groups, suretecsystems.com
+> dn: cn=itsupport,ou=Groups,dc=suretecsystems,dc=com
+> objectClass: posixGroup
+> objectClass: sambaGroupMapping
+> cn: itsupport
+> gidNumber: 1000
+> sambaSID: S-1-5-21-XXX
+> sambaGroupType: 2
+> displayName: itsupport
+> memberUid: ghenry
+> memberUid: joebloggs
+
+and create an LDIF file we can use to add our data to the local database, using
+ some pretty strange choices of new attributes for demonstration purposes:
+
+> [ghenry@suretec test_configs]$ cat test-translucent-add.ldif
+> dn: cn=itsupport,ou=Groups,dc=suretecsystems,dc=com
+> businessCategory: frontend-override
+> carLicense: LIVID
+> employeeType: special
+> departmentNumber: 9999999
+> roomNumber: 41L-535
+
+Searching against the proxy gives:
+
+> [ghenry@suretec test_configs]$ ldapsearch -x -H ldap://127.0.0.1:9001 "(cn=itsupport)"
+> # itsupport, Groups, OxObjects, suretecsystems.com
+> dn: cn=itsupport,ou=Groups,ou=OxObjects,dc=suretecsystems,dc=com
+> objectClass: posixGroup
+> objectClass: sambaGroupMapping
+> cn: itsupport
+> gidNumber: 1003
+> SAMBASID: S-1-5-21-XXX
+> SAMBAGROUPTYPE: 2
+> displayName: itsupport
+> memberUid: ghenry
+> memberUid: joebloggs
+> roomNumber: 41L-535
+> departmentNumber: 9999999
+> employeeType: special
+> carLicense: LIVID
+> businessCategory: frontend-override
+
+Here we can see that the 5 new attributes are added to the remote entry before
+being returned to the our client.
+
+Because we have configured a local attribute to search against:
+
+> overlay translucent
+> translucent_local carLicense
+
+we can also search for that to return the completely fabricated entry:
+
+> ldapsearch -x -H ldap://127.0.0.1:9001 (carLicense=LIVID)
+
+This is an extremely feature because you can then extend a remote directory server
+locally and also search against the local entries.
+
+Note: Because the translucent overlay does not perform any DN rewrites, the local
+ and remote database instances must have the same suffix. Other configurations
+will probably fail with No Such Object and other errors
+
+H3: Further Information
+
+{{:slapo-translucent(5)}}
+
H2: Attribute Uniqueness
H3: Overview
-This overlay can be used with a backend database such as slapd-bdb (5)
+This overlay can be used with a backend database such as {{slapd-bdb(5)}}
to enforce the uniqueness of some or all attributes within a subtree.
H3: Attribute Uniqueness Configuration
+This overlay is only effective on new data from the point the overlay is enabled. To
+check uniqueness for existing data, you can export and import your data again via the
+LDAP Add operation, which will not be suitable for large amounts of data, unlike {{B:slapcat}}.
+
+For the following example, if uniqueness were enforced for the {{B:mail}} attribute,
+the subtree would be searched for any other records which also have a {{B:mail}} attribute
+containing the same value presented with an {{B:add}}, {{B:modify}} or {{B:modrdn}} operation
+which are unique within the configured scope. If any are found, the request is rejected.
+
+Note: If no attributes are specified, for example {{B:ldap:///??sub?}}, then the URI applies to all non-operational attributes. However,
+the keyword {{B:ignore}} can be specified to exclude certain non-operational attributes.
+
+To search at the base dn of the current backend database ensuring uniqueness of the {{B:mail}}
+attribute, we simply add the following configuration:
+
+> overlay unique
+> unique_uri ldap:///?mail?sub?
+
+For an existing entry of:
+
+> dn: cn=gavin,dc=suretecsystems,dc=com
+> objectClass: top
+> objectClass: inetorgperson
+> cn: gavin
+> sn: henry
+> mail: ghenry@suretecsystems.com
+
+and we then try to add a new entry of:
+
+> dn: cn=robert,dc=suretecsystems,dc=com
+> objectClass: top
+> objectClass: inetorgperson
+> cn: robert
+> sn: jones
+> mail: ghenry@suretecsystems.com
+
+would result in an error like so:
+
+> adding new entry "cn=robert,dc=example,dc=com"
+> ldap_add: Constraint violation (19)
+> additional info: some attributes not unique
+
+The overlay can have multiple URIs specified within a domain, allowing complex
+selections of objects and also have multiple {{B:unique_uri}} statements or
+{{B:olcUniqueURI}} attributes which will create independent domains.
+
+For more information and details about the {{B:strict}} and {{B:ignore}} keywords,
+please see the {{:slapo-unique(5)}} man page.
+
+H3: Further Information
+
+{{:slapo-unique(5)}}
+
H2: Value Sorting
H3: Overview
-This overlay can be used to enforce a specific order for the values
-of an attribute when it is returned in a search.
-
+The Value Sorting overlay can be used with a backend database to sort the
+values of specific multi-valued attributes within a subtree. The sorting occurs
+whenever the attributes are returned in a search response.
H3: Value Sorting Configuration
+Sorting can be specified in ascending or descending order, using either numeric
+or alphanumeric sort methods. Additionally, a "weighted" sort can be specified,
+ which uses a numeric weight prepended to the attribute values.
+
+The weighted sort is always performed in ascending order, but may be combined
+with the other methods for values that all have equal weights. The weight is
+specified by prepending an integer weight {<weight>} in front of each value
+of the attribute for which weighted sorting is desired. This weighting factor
+is stripped off and never returned in search results.
+
+Here are a few examples:
+
+> loglevel sync stats
+>
+> database hdb
+> suffix "dc=suretecsystems,dc=com"
+> directory /usr/local/var/openldap-data
+>
+> ......
+>
+> overlay valsort
+> valsort-attr memberUid ou=Groups,dc=suretecsystems,dc=com alpha-ascend
+
+For example, ascend:
+
+> # sharedemail, Groups, suretecsystems.com
+> dn: cn=sharedemail,ou=Groups,dc=suretecsystems,dc=com
+> objectClass: posixGroup
+> objectClass: top
+> cn: sharedemail
+> gidNumber: 517
+> memberUid: admin
+> memberUid: dovecot
+> memberUid: laura
+> memberUid: suretec
+
+For weighted, we change our data to:
+
+> # sharedemail, Groups, suretecsystems.com
+> dn: cn=sharedemail,ou=Groups,dc=suretecsystems,dc=com
+> objectClass: posixGroup
+> objectClass: top
+> cn: sharedemail
+> gidNumber: 517
+> memberUid: {4}admin
+> memberUid: {2}dovecot
+> memberUid: {1}laura
+> memberUid: {3}suretec
+
+and change the config to:
+
+> overlay valsort
+> valsort-attr memberUid ou=Groups,dc=suretecsystems,dc=com weighted
+
+Searching now results in:
+
+> # sharedemail, Groups, OxObjects, suretecsystems.com
+> dn: cn=sharedemail,ou=Groups,ou=OxObjects,dc=suretecsystems,dc=com
+> objectClass: posixGroup
+> objectClass: top
+> cn: sharedemail
+> gidNumber: 517
+> memberUid: laura
+> memberUid: dovecot
+> memberUid: suretec
+> memberUid: admin
+
+
+H3: Further Information
+
+{{:slapo-valsort(5)}}
+
H2: Overlay Stacking
H3: Overview
Overlays can be stacked, which means that more than one overlay
-can be instantiated for each database, or for the frontend.
+can be instantiated for each database, or for the {{EX:frontend}}.
As a consequence, each overlays function is called, if defined,
when overlay execution is invoked.
-Multiple overlays are executed in reverse order (it's a stack, all in all)
+Multiple overlays are executed in reverse order (as a stack)
with respect to their definition in slapd.conf (5), or with respect
to their ordering in the config database, as documented in slapd-config (5).
projects / openldap / blobdiff