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.

       Postfix 2.2 has enhanced query interfaces  for  MySQL  and  PostgreSQL.
       These include features that were previously available only in the Post-
       fix LDAP client. This work also created an opportunity for improvements
       in  the  LDAP  interface.  The  primary  compatibility  issue  is  that
       result_filter (a name that has caused some confusion as to its  meaning
       in the past) has been renamed to result_format.  For backwards compati-
       bility with the pre 2.2 LDAP client, result_filter 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  com-
       patibility 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  parameter
                     (previously called result_filter  see  the  COMPATIBILITY
                     section and below), they expand to the corresponding com-
                     ponents 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

       special_result_attribute (default: empty)
              The  attribute(s)  of  directory entries that can contain DNs or
              URLs. If found, a recursive  subsequent  search  is  done  using
              their values.

                  special_result_attribute = memberdn

              DN  recursion  retrieves  the same result_attributes as the main
              query, including the special attributes for  further  recursion.
              URI processing retrieves only those attributes that are included
              in   the   URI   definition   and   are   *also*    listed    in
              "result_attribute".  If  the  URI lists any of the map's special
              result attributes, these are  also  retrieved  and  used  recur-
              sively.

       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.

                  terminal_result_attribute = 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

              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 not to bind to the LDAP server. Newer LDAP  implemen-
              tations  don't  require clients to bind, which saves time. Exam-
              ple:

                  bind = no

              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

       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

       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 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 Certificate 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 Certificate 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 "never" 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
       Use  "postconf readme_directory" or "postconf html_directory" to locate
       this information.
       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.



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