Provided by: postfix_2.7.1-1_i386 bug

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 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
       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  accessible  as  the name you’ve given the source in its
       definition, 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
       Postfix  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
       compatibility  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
       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  discussion.

       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 $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
              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 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
                     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
                     parameter   (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 specified 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 ’%’ 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
                     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 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
                     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  specified  patterns,  the
                     search is suppressed and returns no results.

                     The  above  %1,  ...,  %9  expansions  are available 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_filter,  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  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
              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  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
              recursively.

       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 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
              implementations don’t require clients to bind, which saves time.
              Example:

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

                                                                 LDAP_TABLE(5)