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.TH nslcd.conf 5 "Feb 2025" "Version 0.9.13" "System Manager's Manual"
.SH NAME
nslcd.conf \- configuration file for LDAP nameservice daemon
.SH DESCRIPTION
The \fInss-pam-ldapd\fR package allows LDAP
directory servers to be used as a primary source of name service
information. (Name service information typically includes users, hosts,
groups, and other such data historically stored in flat files or
NIS.)
.PP
The file \*(T<\fInslcd.conf\fR\*(T> contains the
configuration information for running \fBnslcd\fR (see
\fBnslcd\fR(8)).
The file contains options, one on each line, defining the way
NSS lookups and PAM actions
are mapped to LDAP lookups.
.SH OPTIONS
.SS "RUNTIME OPTIONS"
.TP 
\*(T<\fBthreads\fR\*(T> \fINUM\fR
Specifies the number of threads to start that can handle requests
and perform LDAP queries.
Each thread opens a separate connection to the LDAP
server.
The default is to start 5 threads.
.TP 
\*(T<\fBuid\fR\*(T> \fIUID\fR
This specifies the user id with which the daemon should be run.
This can be a numerical id or a symbolic value.
If no uid is specified no attempt to change the user will be made.
Note that you should use values that don't need LDAP
to resolve.
.TP 
\*(T<\fBgid\fR\*(T> \fIGID\fR
This specifies the group id with which the daemon should be run.
This can be a numerical id or a symbolic value.
If no gid is specified no attempt to change the group will be made.
Note that you should use values that don't need LDAP
to resolve.
.TP 
\*(T<\fBlog\fR\*(T> \fISCHEME\fR [\fILEVEL\fR]
This option controls the way logging is done.
The \fISCHEME\fR argument may either be
\*(T<none\*(T>, \*(T<syslog\*(T> or an absolute
file name.
The \fILEVEL\fR argument is optional and specifies
the log level.
The log level may be one of: \*(T<crit\*(T>,
\*(T<error\*(T>, \*(T<warning\*(T>,
\*(T<notice\*(T>, \*(T<info\*(T> or
\*(T<debug\*(T>. The default log level is \*(T<info\*(T>.
All messages with the specified loglevel or higher are logged.
This option can be supplied multiple times.
If this option is omitted \*(T<syslog info\*(T> is assumed.
.SS "GENERAL CONNECTION OPTIONS"
.TP 
\*(T<\fBuri\fR\*(T> \fIURI\fR ...
Specifies the LDAP URI of the
server to connect to.
The URI scheme may be \*(T<ldap\*(T>,
\*(T<ldapi\*(T> or \*(T<ldaps\*(T>, specifying
LDAP over TCP,
ICP or SSL respectively (if
supported by the LDAP library).

Alternatively, the value \*(T<DNS\*(T> may be
used to try to lookup the server using DNS
SRV records. 
By default the current domain is used but another domain can
be queried by using the
\*(T<DNS:DOMAIN\*(T> syntax.
To convert SRV records for port 389 into an
\*(T<ldaps://\*(T> URI, \*(T<DNSLDAPS\*(T>
can be used. 

When using the \*(T<ldapi\*(T> scheme, \*(T<%2f\*(T> should be used to escape slashes
(e.g. \*(T<ldapi://%2fvar%2frun%2fslapd%2fldapi/\*(T>), although most of the
time this should not be needed.

This option may be specified multiple times and/or with more
URIs on the line, separated by spaces. Normally, only the first
server will be used with the following servers as fall-back (see
\*(T<\fBbind_timelimit\fR\*(T> below).

If LDAP lookups are used for host name resolution,
any host names should be specified as an IP address or name that can be
resolved without using LDAP.
.TP 
\*(T<\fBldap_version\fR\*(T> \fIVERSION\fR
Specifies the version of the LDAP protocol to use.
The default is to use the maximum version supported by the
LDAP library.
.TP 
\*(T<\fBbinddn\fR\*(T> \fIDN\fR
Specifies the distinguished name with which to bind to the directory
server for lookups.
The default is to bind anonymously.
.TP 
\*(T<\fBbindpw\fR\*(T> \fIPASSWORD\fR
Specifies the credentials with which to bind.
This option is only applicable when used with \*(T<\fBbinddn\fR\*(T> above.
If you set this option you should consider changing the permissions
of the \*(T<\fInslcd.conf\fR\*(T> file to only grant access to
the root user.
.TP 
\*(T<\fBrootpwmoddn\fR\*(T> \fIDN\fR
Specifies the distinguished name to use when the root user tries to
modify a user's password using the PAM module.

Note that currently this DN needs to exist as a real entry in the
LDAP directory.
.TP 
\*(T<\fBrootpwmodpw\fR\*(T> \fIPASSWORD\fR
Specifies the credentials with which to bind if the root
user tries to change a user's password.
This option is only applicable when used with
\*(T<\fBrootpwmoddn\fR\*(T> above.
If this option is not specified the PAM module prompts the user for
this password.
If you set this option you should consider changing the permissions
of the \*(T<\fInslcd.conf\fR\*(T> file to only grant access to
the root user.
.SS "SASL AUTHENTICATION OPTIONS"
.TP 
\*(T<\fBsasl_mech\fR\*(T> \fIMECHANISM\fR
Specifies the SASL mechanism to be used when
performing SASL authentication.
.TP 
\*(T<\fBsasl_realm\fR\*(T> \fIREALM\fR
Specifies the SASL realm to be used when performing
SASL authentication.
.TP 
\*(T<\fBsasl_authcid\fR\*(T> \fIAUTHCID\fR
Specifies the authentication identity to be used when performing
SASL authentication.
.TP 
\*(T<\fBsasl_authzid\fR\*(T> \fIAUTHZID\fR
Specifies the authorization identity to be used when performing
SASL authentication.
Must be specified in one of the formats: dn:<distinguished name>
or u:<username>.
.TP 
\*(T<\fBsasl_secprops\fR\*(T> \fIPROPERTIES\fR
Specifies Cyrus SASL security properties.
Allowed values are described in the
\fBldap.conf\fR(5)
manual page.
.TP 
\*(T<\fBsasl_canonicalize\fR\*(T> yes|no
Determines whether the LDAP server host name should
be canonicalised. If this is set to yes the LDAP
library will do a reverse host name lookup.
By default, it is left up to the LDAP library
whether this check is performed or not.
.SS "KERBEROS AUTHENTICATION OPTIONS"
.TP 
\*(T<\fBkrb5_ccname\fR\*(T> \fINAME\fR
Set the name for the GSS-API Kerberos credentials cache.
.SS "SEARCH/MAPPING OPTIONS"
.TP 
\*(T<\fBbase\fR\*(T> [\fIMAP\fR] \fIDN\fR
Specifies the distinguished name (DN)
to use as search base.
This option may be supplied multiple times and all specified bases
will be searched.

A global search base may be specified or a MAP-specific one.
If no MAP-specific search bases are defined the global ones are used.

If, instead of a DN, the value
\fIDOMAIN\fR is specified, the host's
DNS domain is used to construct a search base.
A value of \fI""\fR can be used to indicate an
empty search base (quotes are not otherwise supported for base
values and not all LDAP server configurations support this). 

If this value is not defined an attempt is made to look it up
in the configured LDAP server. If the
LDAP server is unavailable during start-up
\fBnslcd\fR will not start.
.TP 
\*(T<\fBscope\fR\*(T> [\fIMAP\fR] sub[tree]|one[level]|base|children
Specifies the search scope (subtree, onelevel, base or children).
The default scope is subtree; base scope is almost never useful for
name service lookups; children scope is not supported on all servers.
.TP 
\*(T<\fBderef\fR\*(T> never|searching|finding|always
Specifies the policy for dereferencing aliases.
The default policy is to never dereference aliases.
.TP 
\*(T<\fBreferrals\fR\*(T> yes|no
Specifies whether automatic referral chasing should be enabled.
The default behaviour is to chase referrals.
.TP 
\*(T<\fBfilter\fR\*(T> \fIMAP\fR \fIFILTER\fR
The \fIFILTER\fR
is an LDAP search filter to use for a
specific map.
The default filter is a basic search on the
objectClass for the map (e.g. \*(T<(objectClass=posixAccount)\*(T>).
.TP 
\*(T<\fBmap\fR\*(T> \fIMAP\fR \fIATTRIBUTE\fR \fINEWATTRIBUTE\fR
This option allows for custom attributes to be looked up instead of
the default RFC 2307 attributes.
The \fIMAP\fR may be one of
the supported maps below.
The \fIATTRIBUTE\fR is the one as
used in RFC 2307 (e.g. \*(T<userPassword\*(T>,
\*(T<ipProtocolNumber\*(T>, \*(T<macAddress\*(T>, etc.).

The \fINEWATTRIBUTE\fR may be the name of any attribute
as it is available in the directory.

If the \fINEWATTRIBUTE\fR is quoted (")
as \fI"EXPRESSION"\fR
it is treated as an expression which will be evaluated
to build up the actual value used.
See the section on attribute mapping expressions below for more details.

Only some attributes for group, passwd and shadow entries may be mapped
with an expression (because other attributes may be used in search
filters).
For group entries only the \*(T<userPassword\*(T> attribute
may be mapped with an expression.
For passwd entries the following attributes may be mapped with an
expression: \*(T<userPassword\*(T>, \*(T<gidNumber\*(T>,
\*(T<gecos\*(T>, \*(T<homeDirectory\*(T> and
\*(T<loginShell\*(T>.
For shadow entries the following attributes may be mapped with an
expression: \*(T<userPassword\*(T>, \*(T<shadowLastChange\*(T>,
\*(T<shadowMin\*(T>, \*(T<shadowMax\*(T>,
\*(T<shadowWarning\*(T>, \*(T<shadowInactive\*(T>,
\*(T<shadowExpire\*(T> and \*(T<shadowFlag\*(T>.

The \*(T<uidNumber\*(T> and \*(T<gidNumber\*(T>
attributes in the \*(T<passwd\*(T> and \*(T<group\*(T>
maps may be mapped to the \*(T<objectSid\*(T> followed by
the domain SID to derive numeric user and group ids from the SID
(e.g. \*(T<objectSid:S\-1\-5\-21\-3623811015\-3361044348\-30300820\*(T>).

By default all \*(T<userPassword\*(T> attributes are mapped
to the unmatchable password ("*") to avoid accidentally leaking
password information.
.SS "TIMING/RECONNECT OPTIONS"
.TP 
\*(T<\fBbind_timelimit\fR\*(T> \fISECONDS\fR
Specifies the time limit (in seconds) to use when connecting to the
directory server.
This is distinct from the time limit specified in
\*(T<\fBtimelimit\fR\*(T> and affects the set-up of the connection only.
Note that not all LDAP client libraries have support
for setting the connection time out.
The default \*(T<\fBbind_timelimit\fR\*(T> is 10 seconds.
.TP 
\*(T<\fBtimelimit\fR\*(T> \fISECONDS\fR
Specifies the time limit (in seconds) to wait for a response from the
LDAP server.
A value of zero (0), which is the default, is to wait indefinitely for
searches to be completed.
.TP 
\*(T<\fBidle_timelimit\fR\*(T> \fISECONDS\fR
Specifies the period of inactivity (in seconds) after which the
connection to the LDAP server will be closed.
The default is not to time out connections.
.TP 
\*(T<\fBreconnect_sleeptime\fR\*(T> \fISECONDS\fR
Specifies the number of seconds to sleep when connecting to all
LDAP servers fails.
By default 1 second is waited between the first failure and the first
retry.
.TP 
\*(T<\fBreconnect_retrytime\fR\*(T> \fISECONDS\fR
Specifies the time after which the LDAP server is
considered to be permanently unavailable.
Once this time is reached retries will be done only once per this time period.
The default value is 10 seconds.
.PP
Note that the reconnect logic as described above is the mechanism that
is used between \fBnslcd\fR and the LDAP
server. The mechanism between the NSS and
PAM client libraries on one end and
\fBnslcd\fR on the other is simpler with a fixed compiled-in
time out of a 10 seconds for writing to \fBnslcd\fR and
a time out of 60 seconds for reading answers.
\fBnslcd\fR itself has a read time out of 0.5 seconds
and a write time out of 60 seconds.
.SS "SSL/TLS OPTIONS"
.TP 
\*(T<\fBssl\fR\*(T> on|off|start_tls
Specifies whether to use SSL/TLS or not (the default is not to). If
\fIstart_tls\fR
is specified then StartTLS is used rather than raw LDAP over SSL.
Not all LDAP client libraries support both SSL,
StartTLS and all related configuration options.
.TP 
\*(T<\fBtls_reqcert\fR\*(T> never|allow|try|demand|hard
Specifies what checks to perform on a server-supplied certificate.
The meaning of the values is described in the
\fBldap.conf\fR(5)
manual page.
At least one of \*(T<\fBtls_cacertdir\fR\*(T> and
\*(T<\fBtls_cacertfile\fR\*(T> is required if peer verification is
enabled.
.TP 
\*(T<\fBtls_cacertdir\fR\*(T> \fIPATH\fR
Specifies the directory containing X.509 certificates for peer
authentication.
This parameter is ignored when using GnuTLS.
On Debian OpenLDAP is linked against GnuTLS.
.TP 
\*(T<\fBtls_cacertfile\fR\*(T> \fIPATH\fR
Specifies the path to the X.509 certificate for peer authentication.
.TP 
\*(T<\fBtls_randfile\fR\*(T> \fIPATH\fR
Specifies the path to an entropy source.
This parameter is ignored when using GnuTLS.
On Debian OpenLDAP is linked against GnuTLS.
.TP 
\*(T<\fBtls_ciphers\fR\*(T> \fICIPHERS\fR
Specifies the ciphers to use for TLS.
See your TLS implementation's
documentation for further information.
.TP 
\*(T<\fBtls_cert\fR\*(T> \fIPATH\fR
Specifies the path to the file containing the local certificate for
client TLS authentication.
.TP 
\*(T<\fBtls_key\fR\*(T> \fIPATH\fR
Specifies the path to the file containing the private key for client
TLS authentication.
.TP 
\*(T<\fBtls_reqsan\fR\*(T> never|allow|try|demand|hard
Specifies the way server Subject Alternative Name (SAN) is checked in
the server-supplied certificate.
The meaning of the values is described in the
\fBldap.conf\fR(5)
manual page.
.TP 
\*(T<\fBtls_crlcheck\fR\*(T> none|peer|all
Specifies if the Certificate Revocation List (CRL) of the CA should
be used to verify if the server certificates have not been revoked.
The meaning of the values is described in the
\fBldap.conf\fR(5)
manual page.
.TP 
\*(T<\fBtls_crlfile\fR\*(T> \fIPATH\fR
Specifies the path to the file containing a Certificate Revocation List
to be used to verify if the server certificates.
The meaning of the values is described in the
\fBldap.conf\fR(5)
manual page.
.SS "OTHER OPTIONS"
.TP 
\*(T<\fBpagesize\fR\*(T> \fINUMBER\fR
Set this to a number greater than 0 to request paged results from
the LDAP server in accordance with RFC2696.
The default (0) is to not request paged results.

This is useful for LDAP servers that contain a
lot of entries (e.g. more than 500) and limit the number of entries
that are returned with one request.
For OpenLDAP servers you may need to set
\*(T<\fBsizelimit size.prtotal=unlimited\fR\*(T>
for allowing more entries to be returned over multiple pages.
.TP 
\*(T<\fBnss_initgroups_ignoreusers\fR\*(T> user1,user2,...
This option prevents group membership lookups through
LDAP for the specified users. This can be useful
in case of unavailability of the LDAP server.
This option may be specified multiple times.

Alternatively, the value \*(T<ALLLOCAL\*(T> may be
used. With that value nslcd builds a full list of
non-LDAP users on startup.
.TP 
\*(T<\fBnss_min_uid\fR\*(T> \fIUID\fR
This option ensures that LDAP users with a numeric
user id lower than the specified value are ignored. Also requests for
users with a lower user id are ignored.
.TP 
\*(T<\fBnss_uid_offset\fR\*(T> \fINUMBER\fR
This option specifies an offset that is added to all
LDAP numeric user ids.
This can be used to avoid user id collisions with local users or,
when using \*(T<objectSid\*(T> attributes, for compatibility
reasons.

The value from the \*(T<\fBnss_min_uid\fR\*(T> option is evaluated
after applying the offset.
.TP 
\*(T<\fBnss_gid_offset\fR\*(T> \fINUMBER\fR
This option specifies an offset that is added to all
LDAP numeric group ids.
This can be used to avoid user id collisions with local groups or,
when using \*(T<objectSid\*(T> attributes, for compatibility
reasons.
.TP 
\*(T<\fBnss_nested_groups\fR\*(T> yes|no
If this option is set, the \*(T<member\*(T> attribute of a
group may point to another group.
Members of nested groups are also returned in the higher level group
and parent groups are returned when finding groups for a specific user.
The default is not to perform extra searches for nested groups.
.TP 
\*(T<\fBnss_getgrent_skipmembers\fR\*(T> yes|no
If this option is set, the group member list is not retrieved when
looking up groups.
Lookups for finding which groups a user belongs to will remain
functional so the user will likely still get the correct groups
assigned on login.

This can offer a speed-up on systems that have very large groups.
It has the downside of returning inconsistent information about
group membership which may confuse some applications.
This option is not recommended for most configurations.
.TP 
\*(T<\fBnss_disable_enumeration\fR\*(T> yes|no
If this option is set, functions which cause all user/group entries to
be loaded (getpwent(), getgrent(), setspent()) from the directory will
not succeed in doing so.
Applications that depend on being able to sequentially read all users
and/or groups may fail to operate correctly.

This can dramatically reduce LDAP server load in
situations where there are a great number of users and/or groups.
This is typically used in situations where user/program access to
enumerate the entire directory is undesirable, and changing the
behavior of the user/program is not possible.
This option is not recommended for most configurations.
.TP 
\*(T<\fBvalidnames\fR\*(T> \fIREGEX\fR
This option can be used to specify how user and group names are
verified within the system. This pattern is used to check all user and
group names that are requested and returned from LDAP.

The regular expression should be specified as a POSIX extended regular
expression. The expression itself needs to be separated by slash (/)
characters and the 'i' flag may be appended at the end to indicate
that the match should be case-insensitive.
The default value is
\*(T</^[a\-z0\-9._@$()]([a\-z0\-9._@$() \e\e~\-]*[a\-z0\-9._@$()~\-])?$/i\*(T>
.TP 
\*(T<\fBignorecase\fR\*(T> yes|no
This specifies whether or not to perform searches for group,
netgroup, passwd, protocols, rpc, services and shadow maps using
case-insensitive matching.
Setting this to \*(T<yes\*(T> could open up the system
to authorisation bypass vulnerabilities and introduce nscd cache poisoning
vulnerabilities which allow denial of service.
The default is to perform case-sensitive filtering of LDAP search
results for the above maps.
.TP 
\*(T<\fBpam_authc_ppolicy\fR\*(T> yes|no
This option specifies whether password policy controls are requested
and handled from the LDAP server when performing
user authentication.
By default the controls are requested and handled if available.
.TP 
\*(T<\fBpam_authc_search\fR\*(T> \fIFILTER\fR
By default \fBnslcd\fR performs an
LDAP search with the user's credentials after BIND
(authentication) to ensure that the BIND operation was successful.
The default search is a simple check to see if the user's DN exists.

A search filter can be specified that will be used instead.
The same substitutions as with the \*(T<\fBpam_authz_search\fR\*(T>
option will be performed and the search should at least return one
entry.

The value \*(T<BASE\*(T> may be used to force the default
search for the user DN.

The value \*(T<NONE\*(T> may be used to indicate that no
search should be performed after BIND.
Note that some LDAP servers do not always return a
correct error code as a result of a failed BIND operation (e.g. when
an empty password is supplied).
.TP 
\*(T<\fBpam_authz_search\fR\*(T> \fIFILTER\fR
This option allows flexible fine tuning of the authorisation check that
should be performed. The search filter specified is executed and
if any entries match, access is granted, otherwise access is denied.

The search filter can contain the following variable references:
\*(T<$username\*(T>, \*(T<$service\*(T>,
\*(T<$ruser\*(T>, \*(T<$rhost\*(T>,
\*(T<$tty\*(T>, \*(T<$hostname\*(T>,
\*(T<$fqdn\*(T>, 
\*(T<$domain\*(T>, 
\*(T<$dn\*(T>, and \*(T<$uid\*(T>.
These references are substituted in the search filter using the
same syntax as described in the section on attribute mapping
expressions below.

For example, to check that the user has a proper \*(T<authorizedService\*(T>
value if the attribute is present (this almost emulates the
\*(T<\fBpam_check_service_attr\fR\*(T> option in PADL's pam_ldap):

.nf
\*(T<(&(objectClass=posixAccount)(uid=$username)(|(authorizedService=$service)(!(authorizedService=*))))\*(T>
.fi

The \*(T<\fBpam_check_host_attr\fR\*(T> option can be emulated with:

.nf
\*(T<(&(objectClass=posixAccount)(uid=$username)(|(host=$hostname)(host=$fqdn)(host=\e\e*)))\*(T>
.fi

This option may be specified multiple times and all specified searches
should at least return one entry for access to be granted.
.TP 
\*(T<\fBpam_password_prohibit_message\fR\*(T> "\fIMESSAGE\fR"
If this option is set password modification using pam_ldap will be
denied and the specified message will be presented to the user instead.
The message can be used to direct the user to an alternative means
of changing their password.
.TP 
\*(T<\fBreconnect_invalidate\fR\*(T> \fIDB\fR,\fIDB\fR,...
If this option is set, \fBnslcd\fR will try to flush the
specified external caches on start-up and whenever a connection to the
LDAP server is re-established after an error.

\fIDB\fR can refer to one of the nsswitch maps,
in which case \fBnscd\fR is contacted to flush its cache
for the specified database.
If \fIDB\fR is \*(T<nfsidmap\*(T>,
\fBnfsidmap\fR is contacted to clear its cache.

Using this option ensures that external caches are cleared of
incorrect information (typically the absence of users) that may
be present due to unavailability of the LDAP server.
.TP 
\*(T<\fBcache\fR\*(T> \fICACHE\fR \fITIME\fR [\fITIME\fR]
Configure the time entries are kept in the specified internal cache.

The first \fITIME\fR value specifies the time
to keep found entries in the cache.
The second \fITIME\fR value specifies to the
time to remember that a particular entry was not found.
If the second parameter is absent, it is assumed to be the same as
the first.

Time values are specified as a number followed by an
\*(T<s\*(T> for seconds, \*(T<m\*(T> for minutes,
\*(T<h\*(T> for hours or \*(T<d\*(T> for days.
Use \*(T<0\*(T> or \*(T<off\*(T> to disable the
cache.

Currently, only the \*(T<dn2uid\*(T> cache is supported
that is used to remember DN to username lookups that are used when the
\*(T<member\*(T> attribute is used.
The default time value for this cache is \*(T<15m\*(T>.
.SH "SUPPORTED MAPS"
The following maps are supported. They are referenced as
\fIMAP\fR in the options above.
.TP 
alias[es]
Mail aliases.
Note that most mail servers do not use the NSS
interface for requesting mail aliases and parse
\*(T<\fI/etc/aliases\fR\*(T> on their own.
.TP 
ether[s]
Ethernet numbers (mac addresses).
.TP 
group
Posix groups.
.TP 
host[s]
Host names.
.TP 
netgroup
Host and user groups used for access control.
.TP 
network[s]
Network numbers.
.TP 
passwd
Posix users.
.TP 
protocol[s]
Protocol definitions (like in \*(T<\fI/etc/protocols\fR\*(T>).
.TP 
rpc
Remote procedure call names and numbers.
.TP 
service[s]
Network service names and numbers.
.TP 
shadow
Shadow user password information.
.SH "ATTRIBUTE MAPPING EXPRESSIONS"
For some attributes a mapping expression may be used to construct the
resulting value.
This is currently only possible for attributes that do
not need to be used in search filters.
The expressions are a subset of the double quoted string expressions in the
Bourne (POSIX) shell.
Instead of variable substitution, attribute lookups are done on the current
entry and the attribute value is substituted.
The following expressions are supported:
.TP 
\*(T<"${attr}"\*(T> (or \*(T<"$attr"\*(T> for short)
will substitute the value of the attribute
.TP 
\*(T<"${attr:\-word}"\*(T>
(use default) will substitute the value of the attribute or, if the
attribute is not set or empty substitute the word
.TP 
\*(T<"${attr:+word}"\*(T>
(use alternative) will substitute \*(T<word\*(T> if attribute
is set, otherwise substitute the empty string
.TP 
\*(T<"${attr:offset:length}"\*(T>
will substitute \*(T<length\*(T> characters (actually
bytes) starting from position \*(T<offset\*(T> (which
is counted starting at zero); the substituted string is
truncated if it is too long; in particular, it can be of length
zero (if \*(T<length\*(T> is zero or
\*(T<offset\*(T> falls out of the original string)
.TP 
\*(T<"${attr#word}"\*(T>
remove the shortest possible match of \*(T<word\*(T> from the
left of the attribute value
.TP 
\*(T<"${attr##word}"\*(T>
remove the longest possible match of \*(T<word\*(T> from the
left of the attribute value (\fBpynslcd\fR only)
.TP 
\*(T<"${attr%word}"\*(T>
remove the shortest possible match of \*(T<word\*(T> from the
right of the attribute value (\fBpynslcd\fR only)
.TP 
\*(T<"${attr%%word}"\*(T>
remove the longest possible match of \*(T<word\*(T> from the
right of the attribute value (\fBpynslcd\fR only)
.PP
Only the # matching expression is supported in \fBnslcd\fR
and only with the ? wildcard symbol. The \fBpynslcd\fR
implementation supports full matching.
.PP
Quote (\*(T<"\*(T>), dollar (\*(T<$\*(T>) and
backslash (\*(T<\e\*(T>) characters should be escaped with a
backslash (\*(T<\e\*(T>).
.PP
The expressions are inspected to automatically fetch the appropriate
attributes from LDAP.
Some examples to demonstrate how these expressions may be used in
attribute mapping:
.TP 
\*(T<map shadow shadowFlag "${shadowFlag:\-0}"\*(T>
use the \*(T<shadowFlag\*(T> attribute, using the
value 0 as default
.TP 
\*(T<map passd homeDirectory "${homeDirectory:\-/home/$uid}"\*(T>
use the \*(T<uid\*(T> attribute to build a
\*(T<homeDirectory\*(T> value if that attribute is missing
.TP 
\*(T<map shadow shadowExpire "${isDisabled:+100}"\*(T>
if the \*(T<isDisabled\*(T> attribute is set, return 100,
otherwise leave value empty
.TP 
\*(T<map shadow userPassword "${userPassword#{crypt\e}}"\*(T>
strip the {crypt} prefix from the userPassword attribute, returning
the raw hash value
.SH FILES
.TP 
\*(T<\fI/etc/nslcd.conf\fR\*(T>
the main configuration file
.TP 
\*(T<\fI/etc/nsswitch.conf\fR\*(T>
Name Service Switch configuration file
.SH "SEE ALSO"
\fBnslcd\fR(8),
\fBnsswitch.conf\fR(5)
.SH AUTHOR
This manual was written by Arthur de Jong <arthur@arthurdejong.org>
and is based on the
\fBnss_ldap\fR(5)
manual developed by PADL Software Pty Ltd.