LDAP_TABLE(5)                                                    LDAP_TABLE(5)

NAME
       ldap_table - Postfix LDAP client configuration

SYNOPSIS
       postmap -q "string" ldap:/etc/postfix/filename

       postmap -q - ldap:/etc/postfix/filename <inputfile

DESCRIPTION
       The  Postfix  mail system uses optional tables for address
       rewriting or mail routing. These tables are usually in dbm
       or db format.

       Alternatively,  lookup  tables  can  be  specified as LDAP
       databases.

       In order to use LDAP lookups, define an LDAP source  as  a
       lookup table in main.cf, for example:

           alias_maps = ldap:/etc/postfix/ldap-aliases.cf

       The  file /etc/postfix/ldap-aliases.cf has the same format
       as the Postfix main.cf file, and can specify  the  parame-
       ters  described  below.  An example is given at the end of
       this manual.

       This configuration method is available with  Postfix  ver-
       sion  2.1  and later.  See the section "BACKWARDS COMPATI-
       BILITY" below for older Postfix versions.

       For details about LDAP SSL and STARTTLS, see  the  section
       on SSL and STARTTLS below.

BACKWARDS COMPATIBILITY
       For  backwards  compatibility with Postfix version 2.0 and
       earlier, LDAP parameters can also be defined  in  main.cf.
       Specify  as  LDAP  source a name that doesn't begin with a
       slash or a dot.  The LDAP parameters will then be accessi-
       ble as the name you've given the source in its definition,
       an underscore, and the name of the parameter.   For  exam-
       ple,  if  the  map  is specified as "ldap:ldapsource", the
       "server_host" parameter below would be defined in  main.cf
       as "ldapsource_server_host".

       Note:  with  this form, the passwords for the LDAP sources
       are written in main.cf, which is normally  world-readable.
       Support  for this form will be removed in a future Postfix
       version.

       For backwards compatibility with the pre 2.2 LDAP clients,
       result_filter  can  for now be used instead of result_for-
       mat, when the latter parameter is not also set.   The  new
       name  better  reflects the function of the parameter. This
       compatibility  interface  may  be  removed  in  a   future
       release.

LIST MEMBERSHIP
       When  using  LDAP  to  store  lists  such  as $mynetworks,
       $mydestination,   $relay_domains,   $local_recipient_maps,
       etc.,  it  is  important to understand that the table must
       store each list member as a separate key. The table lookup
       verifies  the  *existence*  of the key. See "Postfix lists
       versus tables" in the DATABASE_README document for a  dis-
       cussion.

       Do  NOT create tables that return the full list of domains
       in $mydestination or $relay_domains etc., or IP  addresses
       in $mynetworks.

       DO create tables with each matching item as a key and with
       an arbitrary value. With LDAP databases it is not uncommon
       to return the key itself.

       For  example,  NEVER do this in a map defining $mydestina-
       tion:

           query_filter = domain=*
           result_attribute = domain

       Do this instead:

           query_filter = domain=%s
           result_attribute = domain

GENERAL LDAP PARAMETERS
       In the text below, default values are given  in  parenthe-
       ses.  Note: don't use quotes in these variables; at least,
       not until the Postfix  configuration  routines  understand
       how to deal with quoted strings.

       server_host (default: localhost)
              The  name of the host running the LDAP server, e.g.

                  server_host = ldap.example.com

              Depending on the LDAP client library you're  using,
              it  should  be possible to specify multiple servers
              here, with the library trying them in order  should
              the  first  one fail. It should also be possible to
              give each server  in  the  list  a  different  port
              (overriding server_port below), by naming them like

                  server_host = ldap.example.com:1444

              With OpenLDAP, a (list of) LDAP URLs can be used to
              specify both the hostname(s) and the port(s):

                  server_host = ldap://ldap.example.com:1444
                              ldap://ldap2.example.com:1444

              All  LDAP URLs accepted by the OpenLDAP library are
              supported, including connections over  UNIX  domain
              sockets,  and  LDAP SSL (the last one provided that
              OpenLDAP was compiled with support for SSL):

                  server_host = ldapi://%2Fsome%2Fpath
                              ldaps://ldap.example.com:636

       server_port (default: 389)
              The port the LDAP server listens on, e.g.

                  server_port = 778

       timeout (default: 10 seconds)
              The number of seconds a search can take before tim-
              ing out, e.g.

                  timeout = 5

       search_base (No default; you must configure this)
              The RFC2253 base DN at which to conduct the search,
              e.g.

                  search_base = dc=your, dc=com

              With Postfix 2.2 and later this parameter  supports
              the following '%' expansions:

              %%     This is replaced by a literal '%' character.

              %s     This is replaced by the input key.  RFC 2253
                     quoting  is used to make sure that the input
                     key does not add unexpected  metacharacters.

              %u     When the input key is an address of the form
                     user@domain, %u  is  replaced  by  the  (RFC
                     2253)  quoted  local  part  of  the address.
                     Otherwise, %u  is  replaced  by  the  entire
                     search  string.   If the localpart is empty,
                     the search  is  suppressed  and  returns  no
                     results.

              %d     When the input key is an address of the form
                     user@domain, %d  is  replaced  by  the  (RFC
                     2253)  quoted  domain  part  of the address.
                     Otherwise,  the  search  is  suppressed  and
                     returns no results.

              %[SUD] For  the  search_base  parameter, the upper-
                     case equivalents  of  the  above  expansions
                     behave   identically   to  their  lower-case
                     counter-parts. With the result_format param-
                     eter  (previously  called  result_filter see
                     the COMPATIBILITY section and  below),  they
                     expand  to  the  corresponding components of
                     input key rather than the result value.

              %[1-9] The patterns %1, %2, ... %9 are replaced  by
                     the corresponding most significant component
                     of the input key's domain. If the input  key
                     is user@mail.example.com, then %1 is com, %2
                     is example and %3 is mail. If the input  key
                     is  unqualified  or  does  not  have  enough
                     domain components to satisfy all the  speci-
                     fied  patterns, the search is suppressed and
                     returns no results.

       query_filter (default: mailacceptinggeneralid=%s)
              The RFC2254 filter used to  search  the  directory,
              where %s is a substitute for the address Postfix is
              trying to resolve, e.g.

                  query_filter = (&(mail=%s)(paid_up=true))

              This parameter supports the  following  '%'  expan-
              sions:

              %%     This is replaced by a literal '%' character.
                     (Postfix 2.2 and later).

              %s     This is replaced by the input key.  RFC 2254
                     quoting  is used to make sure that the input
                     key does not add unexpected  metacharacters.

              %u     When the input key is an address of the form
                     user@domain, %u  is  replaced  by  the  (RFC
                     2254)  quoted  local  part  of  the address.
                     Otherwise, %u  is  replaced  by  the  entire
                     search  string.   If the localpart is empty,
                     the search  is  suppressed  and  returns  no
                     results.

              %d     When the input key is an address of the form
                     user@domain, %d  is  replaced  by  the  (RFC
                     2254)  quoted  domain  part  of the address.
                     Otherwise,  the  search  is  suppressed  and
                     returns no results.

              %[SUD] The  upper-case  equivalents  of  the  above
                     expansions behave in the query_filter param-
                     eter   identically   to   their   lower-case
                     counter-parts. With the result_format param-
                     eter  (previously  called  result_filter see
                     the COMPATIBILITY section and  below),  they
                     expand  to  the  corresponding components of
                     input key rather than the result value.

                     The above  %S,  %U  and  %D  expansions  are
                     available with Postfix 2.2 and later.

              %[1-9] The  patterns %1, %2, ... %9 are replaced by
                     the corresponding most significant component
                     of  the input key's domain. If the input key
                     is user@mail.example.com, then %1 is com, %2
                     is  example and %3 is mail. If the input key
                     is  unqualified  or  does  not  have  enough
                     domain  components to satisfy all the speci-
                     fied patterns, the search is suppressed  and
                     returns no results.

                     The  above %1, ..., %9 expansions are avail-
                     able with Postfix 2.2 and later.

              The "domain" parameter described below  limits  the
              input  keys  to addresses in matching domains. When
              the "domain" parameter is non-empty,  LDAP  queries
              for  unqualified  addresses  or  addresses  in non-
              matching  domains  are  suppressed  and  return  no
              results.

              NOTE:  DO  NOT  put  quotes around the query_filter
              parameter.

       result_format (default: %s)
              Called result_filter in Postfix releases  prior  to
              2.2.  Format template applied to result attributes.
              Most commonly used to append (or prepend)  text  to
              the  result.  This parameter supports the following
              '%' expansions:

              %%     This is replaced by a literal '%' character.
                     (Postfix 2.2 and later).

              %s     This  is replaced by the value of the result
                     attribute.  When  result  is  empty  it   is
                     skipped.

              %u     When   the  result  attribute  value  is  an
                     address  of  the  form  user@domain,  %u  is
                     replaced  by  the local part of the address.
                     When the result has an empty localpart it is
                     skipped.

              %d     When  a result attribute value is an address
                     of the form user@domain, %d is  replaced  by
                     the domain part of the attribute value. When
                     the result is unqualified it is skipped.

              %[SUD1-9]
                     The upper-case and decimal digit  expansions
                     interpolate  the  parts  of  the  input  key
                     rather than the result.  Their  behavior  is
                     identical  to that described with query_fil-
                     ter, and in fact because the  input  key  is
                     known in advance, lookups whose key does not
                     contain all the information specified in the
                     result template are suppressed and return no
                     results.

                     The above %S, %U, %D and %1, ..., %9  expan-
                     sions  are  available  with  Postfix 2.2 and
                     later.

              For  example,  using  "result_format  =  smtp:[%s]"
              allows one to use a mailHost attribute as the basis
              of a transport(5) table. After applying the  result
              format,  multiple  values are concatenated as comma
              separated   strings.   The   expansion_limit    and
              size_limit  parameters explained below allow one to
              restrict the number of values in the result,  which
              is  especially useful for maps that should return a
              single value.

              The default value %s specifies that each  attribute
              value should be used as is.

              This  parameter was called result_filter in Postfix
              releases prior to 2.2.  If  no  "result_format"  is
              specified,  the  value  of  "result_filter" will be
              used instead before resorting to the default value.
              This  provides compatibility with old configuration
              files.

              NOTE: DO NOT put quotes around the result format!

       domain (default: no domain list)
              This is a list of domain names, paths to files,  or
              dictionaries.  When specified, only fully qualified
              search keys with  a  *non-empty*  localpart  and  a
              matching  domain  are  eligible  for lookup: 'user'
              lookups, bare domain lookups and "@domain"  lookups
              are  not  performed.  This can significantly reduce
              the query load on the LDAP server.

                  domain = postfix.org, hash:/etc/postfix/searchdomains

              It is best not to use LDAP  to  store  the  domains
              eligible for LDAP lookups.

              NOTE:  DO  NOT  define  this parameter for local(8)
              aliases.

              This feature is available in Postfix 1.0 and later.

       result_attribute (default: maildrop)
              The  attribute(s) Postfix will read from any direc-
              tory entries returned by the lookup, to be resolved
              to an email address.

                  result_attribute = mailbox, maildrop

              Don't  rely  on the default value ("maildrop"). Set
              the result_attribute explicitly in all  ldap  table
              configuration  files. This is particularly relevant
              when no result_attribute is applicable, e.g.  cases
              in   which   leaf_result_attribute   and/or  termi-
              nal_result_attribute are used instead. The  default
              value is harmless if "maildrop" is also listed as a
              leaf or terminal result attribute, but it  is  best
              to not leave this to chance.

       special_result_attribute (default: empty)
              The attribute(s) of directory entries that can con-
              tain DNs or RFC 2255 LDAP URLs. If found, a  recur-
              sive search is performed to retrieve the entry ref-
              erenced by the DN, or the entries  matched  by  the
              URL query.

                  special_result_attribute = memberdn

              DN  recursion  retrieves the same result_attributes
              as the main query, including the special attributes
              for further recursion.

              URL processing retrieves only those attributes that
              are included in both  the  URL  definition  and  as
              result  attributes (ordinary, special, leaf or ter-
              minal) in the Postfix table definition.  If the URL
              lists any of the table's special result attributes,
              these are retrieved and  used  recursively.  A  URL
              that  does  not specify any attribute selection, is
              equivalent (RFC 2255) to a  URL  that  selects  all
              attributes,  in  which case the selected attributes
              will be the full set of result  attributes  in  the
              Postfix table.

              If  an  LDAP URL attribute-descriptor or the corre-
              sponding Postfix LDAP table result  attribute  (but
              not   both)   uses   RFC   2255   sub-type  options
              ("attr;option"), the attribute requested  from  the
              LDAP  server  will  include the sub-type option. In
              all other cases, the URL attribute  and  the  table
              attribute   must  match  exactly.  Attributes  with
              options in both the URL and the Postfix  table  are
              requested only when the options are identical. LDAP
              attribute-descriptor options are very rarely  used,
              most LDAP users will not need to concern themselves
              with this level of nuanced detail.

       terminal_result_attribute (default: empty)
              When one or more  terminal  result  attributes  are
              found in an LDAP entry, all other result attributes
              are ignored and only the terminal result attributes
              are  returned. This is useful for delegating expan-
              sion of group members  to  a  particular  host,  by
              using  an optional "maildrop" attribute on selected
              groups to route the group to a specific host, where
              the  group  is  expanded, possibly via mailing-list
              manager or other special processing.

                  result_attribute =
                  terminal_result_attribute = maildrop

              When using terminal and/or leaf result  attributes,
              the  result_attribute is best set to an empty value
              when it is not used, or else explicitly set to  the
              desired  value,  even  if  it  is the default value
              "maildrop".

              This feature  is  available  with  Postfix  2.4  or
              later.

       leaf_result_attribute (default: empty)
              When  one  or  more  special  result attributes are
              found in a non-terminal  (see  above)  LDAP  entry,
              leaf result attributes are excluded from the expan-
              sion of that entry. This is useful  when  expanding
              groups and the desired mail address attribute(s) of
              the member objects obtained via DN or URI recursion
              are  also  present  in  the  group  object. To only
              return the attribute values from the  leaf  objects
              and  not the containing group, add the attribute to
              the  leaf_result_attribute  list,   and   not   the
              result_attribute  list,  which  is always expanded.
              Note, the default value  of  "result_attribute"  is
              not  empty, you may want to set it explicitly empty
              when using "leaf_result_attribute"  to  expand  the
              group  to  a list of member DN addresses. If groups
              have both member DN references AND attributes  that
              hold  multiple string valued rfc822 addresses, then
              the string  attributes  go  in  "result_attribute".
              The  attributes  that represent the email addresses
              of objects referenced via a DN (or LDAP URI) go  in
              "leaf_result_attribute".

                  result_attribute = memberaddr
                  special_result_attribute = memberdn
                  terminal_result_attribute = maildrop
                  leaf_result_attribute = mail

              When  using terminal and/or leaf result attributes,
              the result_attribute is best set to an empty  value
              when  it is not used, or else explicitly set to the
              desired value, even if  it  is  the  default  value
              "maildrop".

              This  feature  is  available  with  Postfix  2.4 or
              later.

       scope (default: sub)
              The LDAP search scope: sub, base,  or  one.   These
              translate into LDAP_SCOPE_SUBTREE, LDAP_SCOPE_BASE,
              and LDAP_SCOPE_ONELEVEL.

       bind (default: yes)
              Whether or how to bind to the  LDAP  server.  Newer
              LDAP implementations don't require clients to bind,
              which saves time. Example:

                  # Don't bind
                  bind = no
                  # Use SIMPLE bind
                  bind = yes
                  # Use SASL bind
                  bind = sasl

              Postfix versions prior to 2.8 only support "bind  =
              no"  which means don't bind, and "bind = yes" which
              means do a SIMPLE bind.  Postfix 2.8 and later also
              supports "bind = SASL" when compiled with LDAP SASL
              support as described in LDAP_README, it  also  adds
              the  synonyms "bind = none" and "bind = simple" for
              "bind = no" and "bind = yes" respectively. See  the
              SASL section below for additional parameters avail-
              able with "bind = sasl".

              If you do need to bind, you might consider  config-
              uring  Postfix to connect to the local machine on a
              port that's an SSL tunnel to your LDAP  server.  If
              your  LDAP server doesn't natively support SSL, put
              a tunnel (wrapper, proxy, whatever you want to call
              it)  on  that  system  too. This should prevent the
              password from traversing the network in the  clear.

       bind_dn (default: empty)
              If  you  do  have  to bind, do it with this distin-
              guished name. Example:

                  bind_dn = uid=postfix, dc=your, dc=com
              With "bind =  sasl"  (see  above)  the  DN  may  be
              optional  for some SASL mechanisms, don't specify a
              DN if not needed.

       bind_pw (default: empty)
              The password for the distinguished name  above.  If
              you have to use this, you probably want to make the
              map configuration file readable only by the Postfix
              user.  When using the obsolete ldap:ldapsource syn-
              tax, with map parameters in main.cf, it is not pos-
              sible  to securely store the bind password. This is
              because main.cf needs to be world readable to allow
              local accounts to submit mail via the sendmail com-
              mand. Example:

                  bind_pw = postfixpw
              With "bind = sasl" (see above) the password may  be
              optional  for some SASL mechanisms, don't specify a
              password if not needed.

       cache (IGNORED with a warning)

       cache_expiry (IGNORED with a warning)

       cache_size (IGNORED with a warning)
              The above parameters are  NO  LONGER  SUPPORTED  by
              Postfix.   Cache  support  has  been  dropped  from
              OpenLDAP as of release 2.1.13.

       recursion_limit (default: 1000)
              A limit on the nesting depth of DN and URL  special
              result  attribute  evaluation.  The limit must be a
              non-zero positive number.

       expansion_limit (default: 0)
              A limit on the  total  number  of  result  elements
              returned  (as  a  comma separated list) by a lookup
              against the map.  A setting of  zero  disables  the
              limit.  Lookups  fail with a temporary error if the
              limit is exceeded.  Setting the limit to 1  ensures
              that lookups do not return multiple values.

       size_limit (default: $expansion_limit)
              A  limit  on the number of LDAP entries returned by
              any single LDAP search performed  as  part  of  the
              lookup.  A setting of 0 disables the limit.  Expan-
              sion of DN and URL references involves nested  LDAP
              queries,  each  of which is separately subjected to
              this limit.

              Note: even a single LDAP entry can generate  multi-
              ple  lookup results, via multiple result attributes
              and/or multi-valued result attributes.  This  limit
              caps  the  per  search  resource utilization on the
              LDAP server, not  the  final  multiplicity  of  the
              lookup  result.  It is analogous to the "-z" option
              of "ldapsearch".

       dereference (default: 0)
              When to dereference LDAP aliases. (Note  that  this
              has nothing do with Postfix aliases.) The permitted
              values are those legal  for  the  OpenLDAP/UM  LDAP
              implementations:

              0      never

              1      when searching

              2      when locating the base object for the search

              3      always

              See ldap.h or the ldap_open(3) or ldapsearch(1) man
              pages  for more information. And if you're using an
              LDAP package that has other possible values, please
              bring   it   to   the  attention  of  the  postfix-
              users@postfix.org mailing list.

       chase_referrals (default: 0)
              Sets (or clears) LDAP_OPT_REFERRALS (requires  LDAP
              version 3 support).

       version (default: 2)
              Specifies the LDAP protocol version to use.

       debuglevel (default: 0)
              What  level  to  set  for debugging in the OpenLDAP
              libraries.

LDAP SASL PARAMETERS
       If you're using the OpenLDAP libraries compiled with  SASL
       support,  Postfix  2.8 and later built with LDAP SASL sup-
       port as described in LDAP_README can authenticate to  LDAP
       servers via SASL.

       This  enables authentication to the LDAP server via mecha-
       nisms other than a simple password. The added  flexibility
       has  a  cost: it is no longer practical to set an explicit
       timeout on the duration of an LDAP bind  operation.  Under
       adverse  conditions,  whether a SASL bind times out, or if
       it does, the duration of the timeout is determined by  the
       LDAP and SASL libraries.

       It  is  best  to  use tables that use SASL binds via prox-
       ymap(8), this way the requesting process can time-out  the
       proxymap  request.  This  also lets you tailer the process
       environment by overriding the proxymap(8)  import_environ-
       ment setting in master.cf(5). Special environment settings
       may be needed to configure  GSSAPI  credential  caches  or
       other  SASL mechanism specific options. The GSSAPI creden-
       tials used for LDAP lookups may need to be different  than
       say those used for the Postfix SMTP client to authenticate
       to remote servers.

       Using SASL mechanisms requires LDAP  protocol  version  3,
       the  default  protocol version is 2 for backwards compati-
       bility. You must set "version = 3" in addition to "bind  =
       sasl".

       The  following  parameters are relevant to using LDAP with
       SASL

       sasl_mechs (default: empty)
              Space separated list of SASL mechanism(s) to try.

       sasl_realm (default: empty)
              SASL Realm to use, if applicable.

       sasl_authz_id (default: empty)
              The  SASL  authorization  identity  to  assert,  if
              applicable.

       sasl_minssf (default: 0)
              The  minimum required sasl security factor required
              to establish a connection.

LDAP SSL AND STARTTLS PARAMETERS
       If you're using the OpenLDAP libraries compiled  with  SSL
       support,  Postfix  can connect to LDAP SSL servers and can
       issue the STARTTLS command.

       LDAP SSL service can be requested by using a LDAP SSL  URL
       in the server_host parameter:

           server_host = ldaps://ldap.example.com:636

       STARTTLS can be turned on with the start_tls parameter:

           start_tls = yes

       Both  forms  require LDAP protocol version 3, which has to
       be set explicitly with:

           version = 3

       If any of the Postfix programs querying the map is config-
       ured  in  master.cf  to run chrooted, all the certificates
       and keys involved have to be copied to the chroot jail. Of
       course,  the  private  keys should only be readable by the
       user "postfix".

       The following parameters are  relevant  to  LDAP  SSL  and
       STARTTLS:

       start_tls (default: no)
              Whether or not to issue STARTTLS upon connection to
              the server.  Don't set this with LDAP SSL (the  SSL
              session is setup automatically when the TCP connec-
              tion is opened).

       tls_ca_cert_dir  (No   default;   set   either   this   or
       tls_ca_cert_file)
              Directory  containing  X509  Certificate  Authority
              certificates  in  PEM format which are to be recog-
              nized by the client  in  SSL/TLS  connections.  The
              files  each  contain one CA certificate.  The files
              are looked up by the CA subject  name  hash  value,
              which  must hence be available. If more than one CA
              certificate with the same name  hash  value  exist,
              the  extension  must be different (e.g. 9d66eef0.0,
              9d66eef0.1 etc). The search  is  performed  in  the
              ordering  of  the  extension  number, regardless of
              other  properties  of  the  certificates.  Use  the
              c_rehash utility (from the OpenSSL distribution) to
              create the necessary links.

       tls_ca_cert_file  (No  default;   set   either   this   or
       tls_ca_cert_dir)
              File containing the X509 Certificate Authority cer-
              tificates  in PEM format which are to be recognized
              by the client in SSL/TLS connections. This  setting
              takes precedence over tls_ca_cert_dir.

       tls_cert (No default; you must set this)
              File  containing  client's  X509  certificate to be
              used by the client in SSL/ TLS connections.

       tls_key (No default; you must set this)
              File containing the private  key  corresponding  to
              the above tls_cert.

       tls_require_cert (default: no)
              Whether or not to request server's X509 certificate
              and check its validity  when  establishing  SSL/TLS
              connections.   The supported values are no and yes.

              With no, the server certificate trust chain is  not
              checked,  but  with  OpenLDAP  prior to 2.1.13, the
              name in the server certificate must still match the
              LDAP server name. With OpenLDAP 2.0.0 to 2.0.11 the
              server name is not necessarily what you  specified,
              rather  it  is  determined (by reverse lookup) from
              the IP address of the LDAP server connection.  With
              OpenLDAP  prior  to  2.0.13, subjectAlternativeName
              extensions  in  the  LDAP  server  certificate  are
              ignored:  the  server  name  must match the subject
              CommonName. The no setting corresponds to the never
              value  of  TLS_REQCERT in LDAP client configuration
              files.

              Don't use TLS with OpenLDAP 2.0.x  (and  especially
              with x <= 11) if you can avoid it.

              With  yes, the server certificate must be issued by
              a trusted CA, and not be expired. The  LDAP  server
              name  must  match  one  of the name(s) found in the
              certificate (see above for OpenLDAP library version
              dependent behavior). The yes setting corresponds to
              the demand value of TLS_REQCERT in LDAP client con-
              figuration files.

              The "try" and "allow" values of TLS_REQCERT have no
              equivalents  here.  They  are  not  available  with
              OpenLDAP  2.0,  and  in  any case have questionable
              security properties. Either you want  TLS  verified
              LDAP connections, or you don't.

              The yes value only works correctly with Postfix 2.5
              and later, or with OpenLDAP  2.0.  Earlier  Postfix
              releases  or  later  OpenLDAP  releases  don't work
              together with this setting. Support for  LDAP  over
              TLS  was added to Postfix based on the OpenLDAP 2.0
              API.

       tls_random_file (No default)
              Path of a file to  obtain  random  bits  from  when
              /dev/[u]random  is not available, to be used by the
              client in SSL/TLS connections.

       tls_cipher_suite (No default)
              Cipher suite to use in SSL/TLS negotiations.

EXAMPLE
       Here's a basic example for using LDAP to look up  local(8)
       aliases.  Assume that in main.cf, you have:

           alias_maps = hash:/etc/aliases,
                   ldap:/etc/postfix/ldap-aliases.cf

       and in ldap:/etc/postfix/ldap-aliases.cf you have:

           server_host = ldap.example.com
           search_base = dc=example, dc=com

       Upon  receiving  mail  for a local address "ldapuser" that
       isn't found in the  /etc/aliases  database,  Postfix  will
       search the LDAP server listening at port 389 on ldap.exam-
       ple.com.  It will bind anonymously, search for any  direc-
       tory  entries  whose  mailacceptinggeneralid  attribute is
       "ldapuser", read the "maildrop" attributes of those found,
       and build a list of their maildrops, which will be treated
       as RFC822 addresses to which the message  will  be  deliv-
       ered.

SEE ALSO
       postmap(1), Postfix lookup table manager
       postconf(5), configuration parameters
       mysql_table(5), MySQL lookup tables
       pgsql_table(5), PostgreSQL lookup tables

README FILES
       DATABASE_README, Postfix lookup table overview
       LDAP_README, Postfix LDAP client guide

LICENSE
       The Secure Mailer license must be  distributed  with  this
       software.

AUTHOR(S)
       Carsten  Hoeger,  Hery  Rakotoarisoa,  John Hensley, Keith
       Stevenson, LaMont Jones, Liviu Daia, Manuel Guesdon,  Mike
       Mattice,  Prabhat K Singh, Sami Haahtinen, Samuel Tardieu,
       Victor Duchovni, and many others.

                                                                 LDAP_TABLE(5)