1 .TH SLAPO-CHAIN 5 "RELEASEDATE" "OpenLDAP LDVERSION"
2 .\" Copyright 1998-2005 The OpenLDAP Foundation, All Rights Reserved.
3 .\" Copying restrictions apply. See the COPYRIGHT file.
6 slapo-chain \- chain overlay
14 allows automatic referral chasing.
15 Any time a referral is returned (except for bind operations),
16 it chased by using an instance of the ldap backend.
17 If operations are performed with an identity (i.e. after a bind),
18 that identity can be asserted while chasing the referrals
19 by means of the \fIidentity assertion\fP feature of back-ldap
22 for details), which is essentially based on the
24 control (see \fIdraft-weltman-ldapv3-proxy\fP for details.)
25 Referral chasing can be controlled by the client by issuing the
26 \fBchaining\fP control
27 (see \fIdraft-sermersheim-ldap-chaining\fP for details.)
30 The config directives that are specific to the
32 overlay are prefixed by
34 to avoid potential conflicts with directives specific to the underlying
35 database or to other stacked overlays.
38 There are very few chain overlay specific directives; however, directives
39 related to the instances of the \fIldap\fP backend that may be implicitly
40 instantiated by the overlay may assume a special meaning when used
41 in conjunction with this overlay. They are described in
43 and they also need be prefixed by
47 This directive adds the chain overlay to the current backend.
48 The chain overlay may be used with any backend, but it is mainly
49 intended for use with local storage backends that may return referrals.
50 It is useless in conjunction with the \fIslapd-ldap\fP and \fIslapd-meta\fP
51 backends because they already exploit the libldap specific referral chase
53 [Note: this may change in the future, as the \fBldap\fP(5) and
54 \fBmeta\fP(5) backends might no longer chase referrals on their own.]
56 .B chain-chaining [resolve=<r>] [continuation=<c>] [critical]
57 This directive enables the \fIchaining\fP control
58 (see \fIdraft-sermersheim-ldap-chaining\fP for details)
59 with the desired resolve and continuation behaviors and criticality.
60 The \fBresolve\fP parameter refers to the behavior while discovering
61 a resource, namely when accessing the object indicated by the request DN;
62 the \fBcontinuation\fP parameter refers to the behavior while handling
63 intermediate responses, which is mostly significant for the search
64 operation, but may affect extended operations that return intermediate
66 The values \fBr\fP and \fBc\fP can be any of
67 .BR chainingPreferred ,
68 .BR chainingRequired ,
69 .BR referralsPreferred ,
70 .BR referralsRequired .
71 If the \fBcritical\fP flag affects the control criticality if provided.
72 [This control is experimental and its support may change in the future.]
74 .B chain-cache-uri {FALSE|true}
75 This directive instructs the \fIchain\fP overlay to cache
76 connections to URIs parsed out of referrals that are not predefined,
77 to be reused for later chaining.
78 These URIs inherit the properties configured for the underlying
79 \fBslapd-ldap\fP(5) before any occurrence of the \fBchain-uri\fP
80 directive; in detail, they are essentially chained anonymously.
82 .B chain-uri <ldapuri>
83 This directive instantiates a new underlying \fIldap\fP database
84 and instructs it about which URI to contact to chase referrals.
85 As opposed to what stated in \fBslapd-ldap\fP(5), only one URI
86 can appear after this directive; all subsequent \fBslapd-ldap\fP(5)
87 directives prefixed by \fBchain-\fP refer to this specific instance
91 Directives for configuring the underlying ldap database may also
92 be required, as shown in this example:
97 chain-rebind-as-user FALSE
99 chain-uri "ldap://ldap1.example.com"
100 chain-rebind-as-user TRUE
101 chain-idassert-bind bindmethod="simple"
102 binddn="cn=Auth,dc=example,dc=com"
106 chain-uri "ldap://ldap2.example.com"
107 chain-idassert-bind bindmethod="simple"
108 binddn="cn=Auth,dc=example,dc=com"
115 Any valid directives for the ldap database may be used; see
118 Multiple occurrences of the \fBchain-uri\fP directive may appear,
119 to define multiple "trusted" URIs where operations with
120 \fIidentity assertion\fP are chained.
121 All URIs not listed in the configuration are chained anonymously.
122 All \fBslapd-ldap\fP(5) directives appearing before the first
123 occurrence of \fBchain-uri\fP are inherited by all URIs,
124 unless specifically overridden inside each URI configuration.
128 default slapd configuration file
134 Originally implemented by Howard Chu; extended by Pierangelo Masarati.