-# Copyright 1999-2001, The OpenLDAP Foundation, All Rights Reserved.
+# Copyright 1999-2005, The OpenLDAP Foundation, All Rights Reserved.
# COPYING RESTRICTIONS APPLY, see COPYRIGHT.
H1: Security Considerations
OpenLDAP Software is designed to run in a wide variety of computing
environments from tightly-controlled closed networks to the global
-Internet. Hence, OpenLDAP Software provides many different security
+Internet. Hence, OpenLDAP Software supports many different security
mechanisms. This chapter describes these mechanisms and discusses
security considerations for using OpenLDAP Software.
-H2: Host Security
-
H2: Network Security
-H3: Selective Hearing
+H3: Selective Listening
By default, {{slapd}}(8) will listen on both the IPv4 and IPv6 "any"
addresses. It is often desirable to have {{slapd}} listen on select
address/port pairs. For example, listening only on the IPv4 address
-127.0.0.1 will disallow remote access to the directory server.
+{{EX:127.0.0.1}} will disallow remote access to the directory server.
+E.g.:
+
+> slapd -h ldap://127.0.0.1
While the server can be configured to listen on a particular interface
address, this doesn't necessarily restrict access to the server to
only those networks accessible via that interface. To selective
-restrict remote access, it is recommend that an IP Firewall be
-used to restrict access.
+restrict remote access, it is recommend that an {{SECT:IP Firewall}}
+be used to restrict access.
See {{SECT:Command-line Options}} and {{slapd}}(8) for more
information.
H3: IP Firewall
-IP firewall capabilities of the server system can be used to restrict
-access based upon the client's IP address and/or network interface
-used to communicate with the client.
+{{TERM:IP}} firewall capabilities of the server system can be used
+to restrict access based upon the client's IP address and/or network
+interface used to communicate with the client.
-Generally, slapd(8) listens on port 389/tcp for LDAP over TCP (e.g.
-ldap://) and port 636/tcp for LDAP over SSL (e.g. ldaps://).
+Generally, {{slapd}}(8) listens on port 389/tcp for {{F:ldap://}}
+sessions and port 636/tcp for {{F:ldaps://}}) sessions. {{slapd}}(8)
+may be configured to listen on other ports.
As specifics of how to configure IP firewall are dependent on the
particular kind of IP firewall used, no examples are provided here.
H3: TCP Wrappers
-OpenLDAP supports TCP wrappers. TCP wrappers provide a rule-based
-access control system for controlling TCP/IP access to the server.
-For example, the {{host_options}}(5) rule:
+{{slapd}}(8) supports {{TERM:TCP}} Wrappers. TCP Wrappers provide
+a rule-based access control system for controlling TCP/IP access
+to the server. For example, the {{host_options}}(5) rule:
> slapd: 10.0.0.0/255.0.0.0 127.0.0.1 : ALLOW
> slapd: ALL : DENY
-allows only incoming connections from the private network 10 and
-localhost (127.0.0.1) to access the directory service.
+allows only incoming connections from the private network {{F:10.0.0.0}}
+and localhost ({{F:127.0.0.1}}) to access the directory service.
+Note that IP addresses are used as {{slapd}}(8) is not normally
+configured to perform reverse lookups.
It is noted that TCP wrappers require the connection to be accepted.
As significant processing is required just to deny a connection,
-it is generally advised that IP firewall protection be
-used instead of TCP wrappers.
+it is generally advised that IP firewall protection be used instead
+of TCP wrappers.
See {{hosts_access}}(5) for more information on TCP wrapper rules.
+
+
+H2: Data Integrity and Confidentiality Protection
+
+{{TERM[expand]TLS}} (TLS) can be used to provide data integrity and
+confidentiality protection. OpenLDAP supports negotiation of
+{{TERM:TLS}} ({{TERM:SSL}}) via both StartTLS and {{F:ldaps://}}.
+See the {{SECT:Using TLS}} chapter for more information. StartTLS
+is the standard track mechanism.
+
+A number of {{TERM[expand]SASL}} (SASL) mechanisms, such as DIGEST-MD5
+and {{TERM:GSSAPI}}, also provide data integrity and confidentiality
+protection. See the {{SECT:Using SASL}} chapter for more information.
+
+
+H3: Security Strength Factors
+
+The server uses {{TERM[expand]SSF}}s (SSF) to indicate the relative
+strength of protection. A SSF of zero (0) indicates no protections
+are in place. A SSF of one (1) indicates integrity protection are
+in place. A SSF greater than one (>1) roughly correlates to the
+effective encryption key length. For example, {{TERM:DES}} is 56,
+{{TERM:3DES}} is 112, and {{TERM:AES}} 128, 192, or 256.
+
+A number of administrative controls rely on SSFs associated with
+TLS and SASL protection in place on an LDAP session.
+
+{{EX:security}} controls disallow operations when appropriate
+protections are not in place. For example:
+
+> security ssf=1 update_ssf=112
+
+requires integrity protection for all operations and encryption
+protection, 3DES equivalent, for update operations (e.g. add, delete,
+modify, etc.). See {{slapd.conf}}(5) for details.
+
+For fine-grained control, SSFs may be used in access controls. See
+{{SECT:Access Control}} section of the {{SECT:The slapd Configuration
+File}} for more information.
+
+
+H2: Authentication Methods
+
+H3: "simple" method
+
+The LDAP "simple" method has three modes of operation:
+
+* anonymous,
+* unauthenticated, and
+* user/password authenticated.
+
+Anonymous access is obtained by providing no name and no password
+to the "simple" bind operation. Unauthenticated access is obtained
+by providing a name but no password. Authenticated access is obtain
+by providing a valid name and password.
+
+An anonymous bind results in an {{anonymous}} authorization
+association. Anonymous bind mechanism is enabled by default, but
+can be disabled by specifying "{{EX:disallow bind_anon}}" in
+{{slapd.conf}}(5).
+
+An unauthenticated bind also results in an {{anonymous}} authorization
+association. Unauthenticated bind mechanism is disabled by default,
+but can be enabled by specifying "{{EX:allow bind_anon_cred}}" in
+{{slapd.conf}}(5). As a number of LDAP applications mistakenly
+generate unauthenticated bind request when authenticated access was
+intended (that is, they do not ensure a password was provided),
+this mechanism should generally remain disabled.
+
+A successful user/password authenticated bind results in a user
+authorization identity, the provided name, being associated with
+the session. User/password authenticated bind is enabled by default.
+However, as this mechanism itself offers no evesdropping protection
+(e.g., the password is set in the clear), it is recommended that
+it be used only in tightly controlled systems or when the LDAP
+session is protected by other means (e.g., TLS, {{TERM:IPSEC}}).
+Where the administrator relies on TLS to protect the password, it
+is recommended that unprotected authentication be disabled. This
+is done by setting "{{EX:disallow bind_simple_unprotected}}" in
+{{slapd.conf}}(5). The {{EX:security}} directive's {{EX:simple_bind}}
+option provides fine grain control over the level of confidential
+protection to require for {{simple}} user/password authentication.
+
+The user/password authenticated bind mechanism can be completely
+disabled by setting "{{EX:disallow bind_simple}}".
+
+Note: An unsuccessful bind always results in the session having
+an {{anonymous}} authorization association.
+
+
+H3: SASL method
+
+The LDAP {{TERM:SASL}} method allows use of any SASL authentication
+mechanism. The {{SECT:Using SASL}} discusses use of SASL.
+
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