Provided by: krb5-kdc_1.17-6_amd64 bug

NAME

       kdc.conf - Kerberos V5 KDC configuration file

       The kdc.conf file supplements krb5.conf(5) for programs which are typically only used on a
       KDC, such  as  the  krb5kdc(8)  and  kadmind(8)  daemons  and  the  kdb5_util(8)  program.
       Relations  documented  here  may  also  be  specified  in  krb5.conf; for the KDC programs
       mentioned, krb5.conf and kdc.conf will be merged into a single configuration profile.

       Normally, the kdc.conf file is found in the KDC state directory,  /etc/krb5kdc.   You  can
       override the default location by setting the environment variable KRB5_KDC_PROFILE.

       Please  note that you need to restart the KDC daemon for any configuration changes to take
       effect.

STRUCTURE

       The kdc.conf file is set up in the same format as the krb5.conf(5) file.

SECTIONS

       The kdc.conf file may contain the following sections:

                           ┌──────────────┬──────────────────────────────────┐
                           │[kdcdefaults] │ Default values for KDC behavior  │
                           ├──────────────┼──────────────────────────────────┤
                           │[realms]      │ Realm-specific          database │
                           │              │ configuration and settings       │
                           ├──────────────┼──────────────────────────────────┤
                           │[dbdefaults]  │ Default database settings        │
                           ├──────────────┼──────────────────────────────────┤
                           │[dbmodules]   │ Per-database settings            │
                           ├──────────────┼──────────────────────────────────┤
                           │[logging]     │ Controls  how  Kerberos  daemons │
                           │              │ perform logging                  │
                           └──────────────┴──────────────────────────────────┘

   [kdcdefaults]
       Some relations in the [kdcdefaults] section specify default values for realm variables, to
       be  used  if  the  [realms]  subsection  does not contain a relation for the tag.  See the
       [realms] section for the definitions of these relations.

       · host_based_services

       · kdc_listen

       · kdc_ports

       · kdc_tcp_listen

       · kdc_tcp_ports

       · no_host_referral

       · restrict_anonymous_to_tgt

       The following [kdcdefaults] variables have no per-realm equivalent:

       kdc_max_dgram_reply_size
              Specifies the maximum packet size that can be sent over UDP.  The default value  is
              4096 bytes.

       kdc_tcp_listen_backlog
              (Integer.)   Set the size of the listen queue length for the KDC daemon.  The value
              may be limited by OS settings.  The default value is 5.

       spake_preauth_kdc_challenge
              (String.)   Specifies  the  group  for  a  SPAKE  optimistic  challenge.   See  the
              spake_preauth_groups  variable  in libdefaults for possible values.  The default is
              not to issue an optimistic challenge.  (New in release 1.17.)

   [realms]
       Each tag in the [realms] section is the name of a Kerberos realm.  The value of the tag is
       a  subsection  where  the  relations define KDC parameters for that particular realm.  The
       following example shows how to define one parameter for the ATHENA.MIT.EDU realm:

          [realms]
              ATHENA.MIT.EDU = {
                  max_renewable_life = 7d 0h 0m 0s
              }

       The following tags may be specified in a [realms] subsection:

       acl_file
              (String.)  Location of the  access  control  list  file  that  kadmind(8)  uses  to
              determine  which principals are allowed which permissions on the Kerberos database.
              To operate without an ACL file, set this relation to the empty string with acl_file
              =  "".   The  default  value  is  /etc/krb5kdc/kadm5.acl.   For more information on
              Kerberos ACL file see kadm5.acl(5).

       database_module
              (String.)  This relation indicates the name  of  the  configuration  section  under
              [dbmodules] for database-specific parameters used by the loadable database library.
              The default value is the realm name.  If this configuration section does not exist,
              default values will be used for all database parameters.

       database_name
              (String,  deprecated.)   This  relation  specifies  the  location  of  the Kerberos
              database for this realm, if the DB2  module  is  being  used  and  the  [dbmodules]
              configuration  section  does  not  specify  a  database name.  The default value is
              /etc/krb5kdc/principal.

       default_principal_expiration
              (abstime string.)  Specifies the default expiration date of principals  created  in
              this realm.  The default value is 0, which means no expiration date.

       default_principal_flags
              (Flag  string.)   Specifies  the  default  attributes of principals created in this
              realm.  The format for this string is a comma-separated list  of  flags,  with  '+'
              before  each  flag  that  should be enabled and '-' before each flag that should be
              disabled.   The  postdateable,  forwardable,   tgt-based,   renewable,   proxiable,
              dup-skey, allow-tickets, and service flags default to enabled.

              There are a number of possible flags:

              allow-tickets
                     Enabling this flag means that the KDC will issue tickets for this principal.
                     Disabling this flag essentially deactivates the principal within this realm.

              dup-skey
                     Enabling this flag allows the KDC to issue user-to-user service tickets  for
                     this principal.

              forwardable
                     Enabling this flag allows the principal to obtain forwardable tickets.

              hwauth If  this  flag is enabled, then the principal is required to preauthenticate
                     using a hardware device before receiving any tickets.

              no-auth-data-required
                     Enabling this flag prevents PAC or AD-SIGNEDPATH data from  being  added  to
                     service tickets for the principal.

              ok-as-delegate
                     If this flag is enabled, it hints the client that credentials can and should
                     be delegated when authenticating to the service.

              ok-to-auth-as-delegate
                     Enabling this flag allows the principal to use S4USelf tickets.

              postdateable
                     Enabling this flag allows the principal to obtain postdateable tickets.

              preauth
                     If this flag is enabled on  a  client  principal,  then  that  principal  is
                     required  to  preauthenticate to the KDC before receiving any tickets.  On a
                     service principal, enabling this flag means that service  tickets  for  this
                     principal  will  only  be  issued  to  clients  with  a  TGT  that  has  the
                     preauthenticated bit set.

              proxiable
                     Enabling this flag allows the principal to obtain proxy tickets.

              pwchange
                     Enabling this flag forces a password change for this principal.

              pwservice
                     If this flag is enabled, it  marks  this  principal  as  a  password  change
                     service.   This  should  only  be  used  in special cases, for example, if a
                     user's password has expired, then the user  has  to  get  tickets  for  that
                     principal  without going through the normal password authentication in order
                     to be able to change the password.

              renewable
                     Enabling this flag allows the principal to obtain renewable tickets.

              service
                     Enabling this flag allows the the KDC to  issue  service  tickets  for  this
                     principal.   In  release  1.17  and  later, user-to-user service tickets are
                     still allowed if the dup-skey flag is set.

              tgt-based
                     Enabling this  flag  allows  a  principal  to  obtain  tickets  based  on  a
                     ticket-granting-ticket,  rather  than  repeating  the authentication process
                     that was used to obtain the TGT.

       dict_file
              (String.)  Location of the dictionary file containing strings that are not  allowed
              as  passwords.   The  file  should  contain one string per line, with no additional
              whitespace.  If none is specified  or  if  there  is  no  policy  assigned  to  the
              principal, no dictionary checks of passwords will be performed.

       encrypted_challenge_indicator
              (String.)   Specifies  the authentication indicator value that the KDC asserts into
              tickets obtained using FAST encrypted challenge pre-authentication.  New in 1.16.

       host_based_services
              (Whitespace- or comma-separated list.)  Lists services which  will  get  host-based
              referral processing even if the server principal is not marked as host-based by the
              client.

       iprop_enable
              (Boolean value.)  Specifies whether incremental database  propagation  is  enabled.
              The default value is false.

       iprop_master_ulogsize
              (Integer.)   Specifies  the  maximum  number  of  log  entries  to  be retained for
              incremental propagation.  The default value is 1000.  Prior to  release  1.11,  the
              maximum value was 2500.

       iprop_replica_poll
              (Delta  time  string.)   Specifies  how often the replica KDC polls for new updates
              from the master.  The default value is 2m (that is, two minutes).  New  in  release
              1.17.

       iprop_slave_poll
              (Delta  time  string.)  The name for iprop_replica_poll prior to release 1.17.  Its
              value is used as a fallback if iprop_replica_poll is not specified.

       iprop_listen
              (Whitespace- or comma-separated list.)  Specifies the iprop RPC listening addresses
              and/or  ports for the kadmind(8) daemon.  Each entry may be an interface address, a
              port number, or an address and port number separated by a colon.   If  the  address
              contains  colons,  enclose  it in square brackets.  If no address is specified, the
              wildcard address is used.  If kadmind  fails  to  bind  to  any  of  the  specified
              addresses,  it  will  fail to start.  The default (when iprop_enable is true) is to
              bind to the wildcard address at the port specified in iprop_port.  New  in  release
              1.15.

       iprop_port
              (Port  number.)   Specifies the port number to be used for incremental propagation.
              When  iprop_enable  is  true,  this  relation  is  required  in  the  replica   KDC
              configuration  file,  and  this  relation or iprop_listen is required in the master
              configuration file, as there is no default port number.  Port numbers specified  in
              iprop_listen entries will override this port number for the kadmind(8) daemon.

       iprop_resync_timeout
              (Delta  time  string.)  Specifies the amount of time to wait for a full propagation
              to complete.  This is optional in configuration files, and is used by replica  KDCs
              only.  The default value is 5 minutes (5m).  New in release 1.11.

       iprop_logfile
              (File  name.)   Specifies where the update log file for the realm database is to be
              stored.  The default is to use the database_name entry from the realms  section  of
              the krb5 config file, with .ulog appended.  (NOTE: If database_name isn't specified
              in the realms section, perhaps because the LDAP database back end is being used, or
              the  file name is specified in the [dbmodules] section, then the hard-coded default
              for database_name is used.  Determination of the iprop_logfile default  value  will
              not use values from the [dbmodules] section.)

       kadmind_listen
              (Whitespace-   or  comma-separated  list.)   Specifies  the  kadmin  RPC  listening
              addresses and/or ports for the kadmind(8) daemon.  Each entry may be  an  interface
              address, a port number, or an address and port number separated by a colon.  If the
              address contains  colons,  enclose  it  in  square  brackets.   If  no  address  is
              specified,  the  wildcard  address is used.  If kadmind fails to bind to any of the
              specified addresses, it will fail to start.  The default is to bind to the wildcard
              address  at  the port specified in kadmind_port, or the standard kadmin port (749).
              New in release 1.15.

       kadmind_port
              (Port number.)  Specifies the port on which the kadmind(8) daemon is to listen  for
              this  realm.   Port  numbers specified in kadmind_listen entries will override this
              port number.  The assigned port for kadmind is 749, which is used by default.

       key_stash_file
              (String.)  Specifies the location  where  the  master  key  has  been  stored  (via
              kdb5_util  stash).   The  default  is  /etc/krb5kdc/.k5.REALM,  where  REALM is the
              Kerberos realm.

       kdc_listen
              (Whitespace- or comma-separated  list.)   Specifies  the  UDP  listening  addresses
              and/or  ports for the krb5kdc(8) daemon.  Each entry may be an interface address, a
              port number, or an address and port number separated by a colon.   If  the  address
              contains  colons,  enclose  it in square brackets.  If no address is specified, the
              wildcard address is used.  If no port is specified, the standard port (88) is used.
              If  the KDC daemon fails to bind to any of the specified addresses, it will fail to
              start.  The default is to bind to the wildcard address on the standard  port.   New
              in release 1.15.

       kdc_ports
              (Whitespace-  or  comma-separated  list,  deprecated.)  Prior to release 1.15, this
              relation lists the ports for the krb5kdc(8) daemon to listen on for  UDP  requests.
              In  release  1.15 and later, it has the same meaning as kdc_listen if that relation
              is not defined.

       kdc_tcp_listen
              (Whitespace- or comma-separated  list.)   Specifies  the  TCP  listening  addresses
              and/or  ports for the krb5kdc(8) daemon.  Each entry may be an interface address, a
              port number, or an address and port number separated by a colon.   If  the  address
              contains  colons,  enclose  it in square brackets.  If no address is specified, the
              wildcard address is used.  If no port is specified, the standard port (88) is used.
              To  disable  listening  on  TCP,  set  this  relation  to  the  empty  string  with
              kdc_tcp_listen = "".  If the KDC daemon fails to  bind  to  any  of  the  specified
              addresses,  it  will fail to start.  The default is to bind to the wildcard address
              on the standard port.  New in release 1.15.

       kdc_tcp_ports
              (Whitespace- or comma-separated list, deprecated.)  Prior  to  release  1.15,  this
              relation  lists  the ports for the krb5kdc(8) daemon to listen on for UDP requests.
              In release 1.15 and later, it has  the  same  meaning  as  kdc_tcp_listen  if  that
              relation is not defined.

       kpasswd_listen
              (Comma-separated list.)  Specifies the kpasswd listening addresses and/or ports for
              the kadmind(8) daemon.  Each entry may be an interface address, a port  number,  or
              an  address  and port number separated by a colon.  If the address contains colons,
              enclose it in square brackets.  If no address is specified, the wildcard address is
              used.   If kadmind fails to bind to any of the specified addresses, it will fail to
              start.  The default is to bind to the wildcard address at  the  port  specified  in
              kpasswd_port, or the standard kpasswd port (464).  New in release 1.15.

       kpasswd_port
              (Port  number.)  Specifies the port on which the kadmind(8) daemon is to listen for
              password change requests for this realm.  Port numbers specified in  kpasswd_listen
              entries  will  override  this  port  number.  The assigned port for password change
              requests is 464, which is used by default.

       master_key_name
              (String.)  Specifies the name of the principal associated with the master key.  The
              default is K/M.

       master_key_type
              (Key  type  string.)   Specifies  the master key's key type.  The default value for
              this is aes256-cts-hmac-sha1-96.  For a list of all possible values, see Encryption
              types.

       max_life
              (duration  string.)   Specifies  the  maximum time period for which a ticket may be
              valid in this realm.  The default value is 24 hours.

       max_renewable_life
              (duration string.)  Specifies the maximum time period during which a  valid  ticket
              may be renewed in this realm.  The default value is 0.

       no_host_referral
              (Whitespace-  or  comma-separated  list.)   Lists  services  to  block from getting
              host-based referral processing, even if the client marks the  server  principal  as
              host-based  or the service is also listed in host_based_services.  no_host_referral
              = * will disable referral processing altogether.

       reject_bad_transit
              (Boolean value.)  If set to true, the KDC will check the list of  transited  realms
              for  cross-realm tickets against the transit path computed from the realm names and
              the capaths section of its krb5.conf(5) file; if the  path  in  the  ticket  to  be
              issued contains any realms not in the computed path, the ticket will not be issued,
              and an error will be returned to the client instead.   If  this  value  is  set  to
              false,  such  tickets  will  be  issued  anyways,  and  it  will  be left up to the
              application server to validate the realm transit path.

              If the disable-transited-check flag is set in the incoming request, this  check  is
              not  performed at all.  Having the reject_bad_transit option will cause such ticket
              requests to be rejected always.

              This transit path checking and config file  option  currently  apply  only  to  TGS
              requests.

              The default value is true.

       restrict_anonymous_to_tgt
              (Boolean  value.)   If  set  to  true,  the  KDC  will  reject ticket requests from
              anonymous principals to service principals other than the  realm's  ticket-granting
              service.   This  option allows anonymous PKINIT to be enabled for use as FAST armor
              tickets without allowing anonymous authentication to services.  The  default  value
              is false.  New in release 1.9.

       spake_preauth_indicator
              (String.)   Specifies  an  authentication indicator value that the KDC asserts into
              tickets obtained using SPAKE pre-authentication.  The default is  not  to  add  any
              indicators.  This option may be specified multiple times.  New in release 1.17.

       supported_enctypes
              (List  of  key:salt  strings.)   Specifies  the  default  key/salt  combinations of
              principals for this realm.  Any principals created through kadmin(1) will have keys
              of  these  types.  The default value for this tag is aes256-cts-hmac-sha1-96:normal
              aes128-cts-hmac-sha1-96:normal des3-cbc-sha1:normal  arcfour-hmac-md5:normal.   For
              lists of possible values, see Keysalt lists.

   [dbdefaults]
       The [dbdefaults] section specifies default values for some database parameters, to be used
       if the [dbmodules]  subsection  does  not  contain  a  relation  for  the  tag.   See  the
       [dbmodules] section for the definitions of these relations.

       · ldap_kerberos_container_dn

       · ldap_kdc_dn

       · ldap_kdc_sasl_authcid

       · ldap_kdc_sasl_authzid

       · ldap_kdc_sasl_mech

       · ldap_kdc_sasl_realm

       · ldap_kadmind_dn

       · ldap_kadmind_sasl_authcid

       · ldap_kadmind_sasl_authzid

       · ldap_kadmind_sasl_mech

       · ldap_kadmind_sasl_realm

       · ldap_service_password_file

       · ldap_servers

       · ldap_conns_per_server

   [dbmodules]
       The  [dbmodules] section contains parameters used by the KDC database library and database
       modules.  Each tag in the [dbmodules] section is the name of a Kerberos realm or a section
       name specified by a realm's database_module parameter.  The following example shows how to
       define one database parameter for the ATHENA.MIT.EDU realm:

          [dbmodules]
              ATHENA.MIT.EDU = {
                  disable_last_success = true
              }

       The following tags may be specified in a [dbmodules] subsection:

       database_name
              This DB2-specific tag indicates the location of the  database  in  the  filesystem.
              The default is /etc/krb5kdc/principal.

       db_library
              This  tag  indicates the name of the loadable database module.  The value should be
              db2 for the DB2 module, klmdb for the LMDB module, or kldap for the LDAP module.

       disable_last_success
              If set to true, suppresses KDC updates  to  the  "Last  successful  authentication"
              field  of  principal  entries  requiring  preauthentication.  Setting this flag may
              improve performance.  (Principal entries which  do  not  require  preauthentication
              never  update  the  "Last  successful authentication" field.).  First introduced in
              release 1.9.

       disable_lockout
              If set to true, suppresses KDC updates to  the  "Last  failed  authentication"  and
              "Failed password attempts" fields of principal entries requiring preauthentication.
              Setting this flag may improve  performance,  but  also  disables  account  lockout.
              First introduced in release 1.9.

       ldap_conns_per_server
              This  LDAP-specific  tag  indicates  the number of connections to be maintained per
              LDAP server.

       ldap_kdc_dn and ldap_kadmind_dn
              These LDAP-specific tags indicate the default DN for binding to  the  LDAP  server.
              The  krb5kdc(8)  daemon  uses  ldap_kdc_dn,  while  the kadmind(8) daemon and other
              administrative programs use ldap_kadmind_dn.  The kadmind DN must have  the  rights
              to read and write the Kerberos data in the LDAP database.  The KDC DN must have the
              same rights, unless disable_lockout and disable_last_success  are  true,  in  which
              case  it  only  needs  to  have  rights  to read the Kerberos data.  These tags are
              ignored   if   a   SASL   mechanism   is    set    with    ldap_kdc_sasl_mech    or
              ldap_kadmind_sasl_mech.

       ldap_kdc_sasl_mech and ldap_kadmind_sasl_mech
              These  LDAP-specific tags specify the SASL mechanism (such as EXTERNAL) to use when
              binding to the LDAP server.  New in release 1.13.

       ldap_kdc_sasl_authcid and ldap_kadmind_sasl_authcid
              These LDAP-specific tags specify the  SASL  authentication  identity  to  use  when
              binding  to  the  LDAP  server.   Not all SASL mechanisms require an authentication
              identity.  If the SASL mechanism requires  a  secret  (such  as  the  password  for
              DIGEST-MD5),     these    tags    also    determine    the    name    within    the
              ldap_service_password_file where the secret is stashed.  New in release 1.13.

       ldap_kdc_sasl_authzid and ldap_kadmind_sasl_authzid
              These LDAP-specific tags specify  the  SASL  authorization  identity  to  use  when
              binding  to  the  LDAP  server.   In  most  circumstances  they  do  not need to be
              specified.  New in release 1.13.

       ldap_kdc_sasl_realm and ldap_kadmind_sasl_realm
              These LDAP-specific tags specify the SASL realm to use when  binding  to  the  LDAP
              server.  In most circumstances they do not need to be set.  New in release 1.13.

       ldap_kerberos_container_dn
              This  LDAP-specific  tag  indicates  the DN of the container object where the realm
              objects will be located.

       ldap_servers
              This LDAP-specific tag indicates the list of LDAP servers that the Kerberos servers
              can connect to.  The list of LDAP servers is whitespace-separated.  The LDAP server
              is specified by a LDAP URI.  It is recommended to use  ldapi:  or  ldaps:  URLs  to
              connect to the LDAP server.

       ldap_service_password_file
              This LDAP-specific tag indicates the file containing the stashed passwords (created
              by kdb5_ldap_util stashsrvpw) for the ldap_kdc_dn and ldap_kadmind_dn  objects,  or
              for   the   ldap_kdc_sasl_authcid   or  ldap_kadmind_sasl_authcid  names  for  SASL
              authentication.  This file must be kept secure.

       mapsize
              This LMDB-specific tag indicates the maximum size of the two database  environments
              in  megabytes.   The  default  value  is  128.   Increase  this  value  to  address
              "Environment mapsize limit reached" errors.  New in release 1.17.

       max_readers
              This LMDB-specific tag indicates the maximum number of concurrent reading processes
              for the databases.  The default value is 128.  New in release 1.17.

       nosync This  LMDB-specific  tag  can be set to improve the throughput of kadmind and other
              administrative agents, at the expense of durability (recent  database  changes  may
              not  survive  a  power  outage  or  other  sudden  reboot).  It does not affect the
              throughput of the KDC.  The default value is false.  New in release 1.17.

       unlockiter
              If set to true, this DB2-specific tag causes iteration operations  to  release  the
              database  lock  while  processing  each  principal.   Setting this flag to true can
              prevent extended blocking of KDC or kadmin operations when dumps of large databases
              are in progress.  First introduced in release 1.13.

       The  following  tag  may be specified directly in the [dbmodules] section to control where
       database modules are loaded from:

       db_module_dir
              This tag controls where the plugin system looks for database  modules.   The  value
              should be an absolute path.

   [logging]
       The  [logging]  section  indicates  how krb5kdc(8) and kadmind(8) perform logging.  It may
       contain the following relations:

       admin_server
              Specifies how kadmind(8) performs logging.

       kdc    Specifies how krb5kdc(8) performs logging.

       default
              Specifies how either daemon performs logging in the absence of  relations  specific
              to the daemon.

       debug  (Boolean  value.)  Specifies whether debugging messages are included in log outputs
              other than SYSLOG.  Debugging messages are always included in the system log output
              because  syslog  performs  its own priority filtering.  The default value is false.
              New in release 1.15.

       Logging specifications may have the following forms:

       FILE=filename or FILE:filename
              This value causes the daemon's logging messages to go to the filename.   If  the  =
              form is used, the file is overwritten.  If the : form is used, the file is appended
              to.

       STDERR This value causes the daemon's logging messages to go to its standard error stream.

       CONSOLE
              This value causes the daemon's logging messages to go to the console, if the system
              supports it.

       DEVICE=<devicename>
              This causes the daemon's logging messages to go to the specified device.

       SYSLOG[:severity[:facility]]
              This causes the daemon's logging messages to go to the system log.

              For  backward  compatibility,  a  severity  argument  may be specified, and must be
              specified in order to specify a facility.  This argument will be ignored.

              The facility argument specifies the facility under which the messages  are  logged.
              This  may  be any of the following facilities supported by the syslog(3) call minus
              the LOG_ prefix: KERN, USER, MAIL, DAEMON, AUTH, LPR, NEWS, UUCP, CRON, and  LOCAL0
              through LOCAL7.  If no facility is specified, the default is AUTH.

       In  the following example, the logging messages from the KDC will go to the console and to
       the system log under the facility LOG_DAEMON with default severity of  LOG_INFO;  and  the
       logging   messages   from   the  administrative  server  will  be  appended  to  the  file
       /var/adm/kadmin.log and sent to the device /dev/tty04.

          [logging]
              kdc = CONSOLE
              kdc = SYSLOG:INFO:DAEMON
              admin_server = FILE:/var/adm/kadmin.log
              admin_server = DEVICE=/dev/tty04

   [otp]
       Each subsection of [otp] is the name of an OTP token type.  The tags within the subsection
       define  the  configuration  required  to  forward  a One Time Password request to a RADIUS
       server.

       For each token type, the following tags may be specified:

       server This is the server to send the RADIUS request  to.   It  can  be  a  hostname  with
              optional  port,  an ip address with optional port, or a Unix domain socket address.
              The default is /etc/krb5kdc/<name>.socket.

       secret This tag indicates a filename (which may be relative  to  /etc/krb5kdc)  containing
              the  secret  used  to  encrypt the RADIUS packets.  The secret should appear in the
              first line of the file by itself; leading and trailing whitespace on the line  will
              be  removed.   If  the value of server is a Unix domain socket address, this tag is
              optional, and an empty secret will be used if it is not specified.  Otherwise, this
              tag is required.

       timeout
              An  integer which specifies the time in seconds during which the KDC should attempt
              to contact the RADIUS server.  This tag is the total time across  all  retries  and
              should  be less than the time which an OTP value remains valid for.  The default is
              5 seconds.

       retries
              This tag specifies the number of retries to make to the RADIUS server.  The default
              is 3 retries (4 tries).

       strip_realm
              If  this  tag is true, the principal without the realm will be passed to the RADIUS
              server.  Otherwise, the realm will be included.  The default value is true.

       indicator
              This tag specifies an authentication indicator to be included in the ticket if this
              token  type  is used to authenticate.  This option may be specified multiple times.
              (New in release 1.14.)

       In the following example, requests are sent to a remote server via UDP:

          [otp]
              MyRemoteTokenType = {
                  server = radius.mydomain.com:1812
                  secret = SEmfiajf42$
                  timeout = 15
                  retries = 5
                  strip_realm = true
              }

       An implicit default token type  named  DEFAULT  is  defined  for  when  the  per-principal
       configuration  does  not specify a token type.  Its configuration is shown below.  You may
       override this token type to something applicable for your situation:

          [otp]
              DEFAULT = {
                  strip_realm = false
              }

PKINIT OPTIONS

       NOTE:
          The  following  are  pkinit-specific  options.   These  values  may  be  specified   in
          [kdcdefaults]  as  global  defaults, or within a realm-specific subsection of [realms].
          Also note  that  a  realm-specific  value  over-rides,  does  not  add  to,  a  generic
          [kdcdefaults] specification.  The search order is:

       1. realm-specific subsection of [realms]:

             [realms]
                 EXAMPLE.COM = {
                     pkinit_anchors = FILE:/usr/local/example.com.crt
                 }

       2. generic value in the [kdcdefaults] section:

             [kdcdefaults]
                 pkinit_anchors = DIR:/usr/local/generic_trusted_cas/

       For  information about the syntax of some of these options, see Specifying PKINIT identity
       information in krb5.conf(5).

       pkinit_anchors
              Specifies the location of trusted anchor (root) certificates which the  KDC  trusts
              to  sign client certificates.  This option is required if pkinit is to be supported
              by the KDC.  This option may be specified multiple times.

       pkinit_dh_min_bits
              Specifies the minimum number of bits the KDC is willing to accept  for  a  client's
              Diffie-Hellman key.  The default is 2048.

       pkinit_allow_upn
              Specifies  that the KDC is willing to accept client certificates with the Microsoft
              UserPrincipalName (UPN) Subject Alternative Name (SAN).  This means the KDC accepts
              the  binding  of  the  UPN  in the certificate to the Kerberos principal name.  The
              default value is false.

              Without this option, the KDC will only accept certificates with  the  id-pkinit-san
              as  defined  in  RFC 4556.  There is currently no option to disable SAN checking in
              the KDC.

       pkinit_eku_checking
              This option specifies what Extended Key Usage (EKU) values the KDC  is  willing  to
              accept in client certificates.  The values recognized in the kdc.conf file are:

              kpClientAuth
                     This  is  the default value and specifies that client certificates must have
                     the id-pkinit-KPClientAuth EKU as defined in RFC 4556.

              scLogin
                     If scLogin is specified, client certificates with the Microsoft  Smart  Card
                     Login EKU (id-ms-kp-sc-logon) will be accepted.

              none   If none is specified, then client certificates will not be checked to verify
                     they have an acceptable EKU.  The use of this option is not recommended.

       pkinit_identity
              Specifies the location of the KDC's X.509 identity  information.   This  option  is
              required if pkinit is to be supported by the KDC.

       pkinit_indicator
              Specifies an authentication indicator to include in the ticket if pkinit is used to
              authenticate.  This option may be specified multiple times.  (New in release 1.14.)

       pkinit_pool
              Specifies the location of intermediate certificates which may be used by the KDC to
              complete the trust chain between a client's certificate and a trusted anchor.  This
              option may be specified multiple times.

       pkinit_revoke
              Specifies the location of Certificate Revocation List (CRL) information to be  used
              by  the KDC when verifying the validity of client certificates.  This option may be
              specified multiple times.

       pkinit_require_crl_checking
              The default certificate  verification  process  will  always  check  the  available
              revocation  information  to  see  if a certificate has been revoked.  If a match is
              found for the certificate in a CRL, verification fails.  If the  certificate  being
              verified is not listed in a CRL, or there is no CRL present for its issuing CA, and
              pkinit_require_crl_checking is false, then verification succeeds.

              However, if pkinit_require_crl_checking is true and there  is  no  CRL  information
              available for the issuing CA, then verification fails.

              pkinit_require_crl_checking  should  be  set  to  true  if  the policy is such that
              up-to-date CRLs must be present for every CA.

       pkinit_require_freshness
              Specifies whether to require  clients  to  include  a  freshness  token  in  PKINIT
              requests.  The default value is false.  (New in release 1.17.)

ENCRYPTION TYPES

       Any tag in the configuration files which requires a list of encryption types can be set to
       some combination of  the  following  strings.   Encryption  types  marked  as  "weak"  are
       available for compatibility but not recommended for use.

                 ┌─────────────────────────────────┬──────────────────────────────────┐
                 │des3-cbc-raw                     │ Triple DES cbc mode raw (weak)   │
                 ├─────────────────────────────────┼──────────────────────────────────┤
                 │des3-cbc-sha1     des3-hmac-sha1 │ Triple   DES   cbc   mode   with │
                 │des3-cbc-sha1-kd                 │ HMAC/sha1                        │
                 ├─────────────────────────────────┼──────────────────────────────────┤
                 │aes256-cts-hmac-sha1-96          │ AES-256  CTS  mode  with  96-bit │
                 │aes256-cts aes256-sha1           │ SHA-1 HMAC                       │
                 ├─────────────────────────────────┼──────────────────────────────────┤
                 │aes128-cts-hmac-sha1-96          │ AES-128  CTS  mode  with  96-bit │
                 │aes128-cts aes128-sha1           │ SHA-1 HMAC                       │
                 ├─────────────────────────────────┼──────────────────────────────────┤
                 │aes256-cts-hmac-sha384-192       │ AES-256 CTS  mode  with  192-bit │
                 │aes256-sha2                      │ SHA-384 HMAC                     │
                 ├─────────────────────────────────┼──────────────────────────────────┤
                 │aes128-cts-hmac-sha256-128       │ AES-128 CTS  mode  with  128-bit │
                 │aes128-sha2                      │ SHA-256 HMAC                     │
                 ├─────────────────────────────────┼──────────────────────────────────┤
                 │arcfour-hmac            rc4-hmac │ RC4 with HMAC/MD5                │
                 │arcfour-hmac-md5                 │                                  │
                 ├─────────────────────────────────┼──────────────────────────────────┤
                 │arcfour-hmac-exp    rc4-hmac-exp │ Exportable   RC4  with  HMAC/MD5 │
                 │arcfour-hmac-md5-exp             │ (weak)                           │
                 ├─────────────────────────────────┼──────────────────────────────────┤
                 │camellia256-cts-cmac             │ Camellia-256 CTS mode with CMAC  │
                 │camellia256-cts                  │                                  │
                 ├─────────────────────────────────┼──────────────────────────────────┤
                 │camellia128-cts-cmac             │ Camellia-128 CTS mode with CMAC  │
                 │camellia128-cts                  │                                  │
                 ├─────────────────────────────────┼──────────────────────────────────┤
                 │des3                             │ The    triple    DES     family: │
                 │                                 │ des3-cbc-sha1                    │
                 ├─────────────────────────────────┼──────────────────────────────────┤
                 │aes                              │ The          AES         family: │
                 │                                 │ aes256-cts-hmac-sha1-96,         │
                 │                                 │ aes128-cts-hmac-sha1-96,         │
                 │                                 │ aes256-cts-hmac-sha384-192,  and │
                 │                                 │ aes128-cts-hmac-sha256-128       │
                 ├─────────────────────────────────┼──────────────────────────────────┤
                 │rc4                              │ The RC4 family: arcfour-hmac     │
                 ├─────────────────────────────────┼──────────────────────────────────┤
                 │camellia                         │ The       Camellia       family: │
                 │                                 │ camellia256-cts-cmac         and │
                 │                                 │ camellia128-cts-cmac             │
                 └─────────────────────────────────┴──────────────────────────────────┘

       The  string  DEFAULT  can be used to refer to the default set of types for the variable in
       question.  Types or families can be removed from the current list by prefixing them with a
       minus  sign ("-").  Types or families can be prefixed with a plus sign ("+") for symmetry;
       it has the same meaning as just listing the type or family.  For example,  "DEFAULT  -rc4"
       would  be  the  default set of encryption types with RC4 types removed, and "des3 DEFAULT"
       would be the default set of encryption types with triple DES types moved to the front.

       While aes128-cts and aes256-cts are supported for all Kerberos operations,  they  are  not
       supported  by  very  old  versions  of our GSSAPI implementation (krb5-1.3.1 and earlier).
       Services running versions of krb5 without AES support must not  be  given  keys  of  these
       encryption types in the KDC database.

       The  aes128-sha2  and  aes256-sha2  encryption  types  are  new in release 1.15.  Services
       running versions of krb5 without support for these newer  encryption  types  must  not  be
       given keys of these encryption types in the KDC database.

KEYSALT LISTS

       Kerberos  keys  for  users  are  usually  derived  from  passwords.  Kerberos commands and
       configuration parameters that affect generation of keys  take  lists  of  enctype-salttype
       ("keysalt")  pairs, known as keysalt lists.  Each keysalt pair is an enctype name followed
       by a salttype name, in the format enc:salt.  Individual keysalt list members are separated
       by comma (",") characters or space characters.  For example:

          kadmin -e aes256-cts:normal,aes128-cts:normal

       would  start  up kadmin so that by default it would generate password-derived keys for the
       aes256-cts and aes128-cts encryption types, using a normal salt.

       To ensure that people who happen to pick the same password  do  not  have  the  same  key,
       Kerberos  5 incorporates more information into the key using something called a salt.  The
       supported salt types are as follows:

                             ┌──────────┬──────────────────────────────────┐
                             │normal    │ default for Kerberos Version 5   │
                             ├──────────┼──────────────────────────────────┤
                             │v4        │ the only type used  by  Kerberos │
                             │          │ Version 4 (no salt)              │
                             ├──────────┼──────────────────────────────────┤
                             │norealm   │ same  as  the  default,  without │
                             │          │ using realm information          │
                             ├──────────┼──────────────────────────────────┤
                             │onlyrealm │ uses only realm  information  as │
                             │          │ the salt                         │
                             ├──────────┼──────────────────────────────────┤
                             │afs3      │ AFS  version  3,  only  used for │
                             │          │ compatibility with Kerberos 4 in │
                             │          │ AFS                              │
                             ├──────────┼──────────────────────────────────┤
                             │special   │ generate a random salt           │
                             └──────────┴──────────────────────────────────┘

SAMPLE KDC.CONF FILE

       Here's an example of a kdc.conf file:

          [kdcdefaults]
              kdc_listen = 88
              kdc_tcp_listen = 88
          [realms]
              ATHENA.MIT.EDU = {
                  kadmind_port = 749
                  max_life = 12h 0m 0s
                  max_renewable_life = 7d 0h 0m 0s
                  master_key_type = aes256-cts-hmac-sha1-96
                  supported_enctypes = aes256-cts-hmac-sha1-96:normal aes128-cts-hmac-sha1-96:normal
                  database_module = openldap_ldapconf
              }

          [logging]
              kdc = FILE:/usr/local/var/krb5kdc/kdc.log
              admin_server = FILE:/usr/local/var/krb5kdc/kadmin.log

          [dbdefaults]
              ldap_kerberos_container_dn = cn=krbcontainer,dc=mit,dc=edu

          [dbmodules]
              openldap_ldapconf = {
                  db_library = kldap
                  disable_last_success = true
                  ldap_kdc_dn = "cn=krbadmin,dc=mit,dc=edu"
                      # this object needs to have read rights on
                      # the realm container and principal subtrees
                  ldap_kadmind_dn = "cn=krbadmin,dc=mit,dc=edu"
                      # this object needs to have read and write rights on
                      # the realm container and principal subtrees
                  ldap_service_password_file = /etc/kerberos/service.keyfile
                  ldap_servers = ldaps://kerberos.mit.edu
                  ldap_conns_per_server = 5
              }

FILES

       /etc/krb5kdc/kdc.conf

SEE ALSO

       krb5.conf(5), krb5kdc(8), kadm5.acl(5)

AUTHOR

       MIT

COPYRIGHT

       1985-2019, MIT