    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 Post-
           fix main.cf file, and can specify the parameters  described  below.  An
           example is given at the end of this manual.

           This  configuration  method  is  available with Postfix version 2.1 and
           later.  See the section "BACKWARDS COMPATIBILITY" below for older Post-
           fix 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 accessible as the name you've given the source in its def-
           inition, an underscore, and the name of the parameter.  For example, 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_fil-
           ter  can  for  now  be  used  instead of result_format, 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 under-
           stand 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 discussion.

           Do NOT create tables that return the full list of domains in  $mydesti-
           nation 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 $mydestination:

               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 parentheses.  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 try-
                  ing  them  in order should the first one fail. It should also be
                  possible to give each server in the list a different port (over-
                  riding 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 timing 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  unex-
                         pected 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  sup-
                         pressed 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  parame-
                         ter  (previously called result_filter see the COMPATIBIL-
                         ITY 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 corre-
                         sponding 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 specified patterns, the search is sup-
                         pressed 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 '%' expansions:

                  %%     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  unex-
                         pected 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  sup-
                         pressed 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  parameter  identically  to  their
                         lower-case counter-parts. With the result_format  parame-
                         ter  (previously called result_filter see the COMPATIBIL-
                         ITY 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  corre-
                         sponding  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 specified patterns, the search is sup-
                         pressed and returns no results.

                         The above %1, ..., %9 expansions are available with Post-
                         fix 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  sup-
                         pressed and return no results.

                         The  above  %S,  %U,  %D  and  %1, ..., %9 expansions 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  configura-
                  tion 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 directory 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
                  terminal_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  contain  DNs  or
                  RFC 2255 LDAP URLs. If found, a recursive search is performed to
                  retrieve the entry referenced 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 terminal) 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 corresponding 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 ter-
                  minal  result  attributes are returned. This is useful for dele-
                  gating expansion 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 expansion 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  implemen-
                  tations  don't  require clients to bind, which saves time. Exam-
                  ple:

                      # 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 available with "bind = sasl".

                  If you do need to bind, you might consider  configuring  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  sup-
                  port  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 distinguished 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 syntax, with map parameters in  main.cf,  it  is
                  not  possible  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 command. 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 num-
                  ber.

           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 dis-
                  ables  the  limit.   Expansion 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 multiple lookup
                  results, via  multiple  result  attributes  and/or  multi-valued
                  result  attributes. This limit caps the per search resource uti-
                  lization 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 support as described in
           LDAP_README can authenticate to LDAP servers via SASL.

           This enables authentication to the LDAP  server  via  mechanisms  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 proxymap(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_environment setting in master.cf(5).  Special  environment  set-
           tings may be needed to configure GSSAPI credential caches or other SASL
           mechanism specific  options.  The  GSSAPI  credentials  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 compatibility. You must set "ver-
           sion = 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, Post-
           fix 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 explic-
           itly with:

               version = 3

           If  any  of the Postfix programs querying the map is configured in mas-
           ter.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 automati-
                  cally when the TCP connection is opened).

           tls_ca_cert_dir (No default; set either this or tls_ca_cert_file)
                  Directory containing X509 Certification  Authority  certificates
                  in  PEM  format  which  are  to  be  recognized 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 prop-
                  erties 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 Certification Authority certificates 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 sup-
                  ported 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 certifi-
                  cate 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 configuration  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 veri-
                  fied 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 listen-
           ing at port 389 on ldap.example.com.  It will bind anonymously,  search
           for  any  directory  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 delivered.

    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, LaM-
           ont Jones, Liviu Daia, Manuel Guesdon, Mike Mattice, Prabhat  K  Singh,
           Sami Haahtinen, Samuel Tardieu, Victor Duchovni, and many others.

                                                                     LDAP_TABLE(5)