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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.

       Postfix 2.2 has enhanced query interfaces  for  MySQL  and
       PostgreSQL.   These  include features that were previously
       available only in the Postfix LDAP client. This work  also
       created an opportunity for improvements in the LDAP inter-
       face. The primary compatibility issue is that  result_fil-
       ter (a name that has caused some confusion as to its mean-
       ing in the past) has been renamed to  result_format.   For
       backwards  compatibility  with  the  pre  2.2 LDAP client,
       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
                     [email protected],  %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
                     [email protected],  %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 [email protected], 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
                     [email protected],  %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
                     [email protected],  %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 [email protected], 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 saerch 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  [email protected],  %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 [email protected], %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/search-
              domains

              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

       special_result_attribute (No default)
              The attribute(s) of directory entries that can con-
              tain DNs or URLs. If found, a recursive  subsequent
              search is done using their values.
                  special_result_attribute = member

              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 recursively.

       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 implementations don't require clients to bind,
              which saves time. Example:
                  bind = no

              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

       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

       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-
              [email protected] 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,  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.

       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.my.com
           search_base = dc=my, 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.my.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,  LaMont Jones, Liviu Daia, Manuel Guesdon, Mike
       Mattice, Prabhat K Singh, Sami Haahtinen, Samuel  Tardieu,
       Victor Duchovni, and many others.

                                                                 LDAP_TABLE(5)