Provided by: krb5-kdc_1.17-1_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.

       des_crc_session_supported
              (Boolean value).  If set to true, the  KDC  will  assume  that  service  principals
              support   des-cbc-crc   for   session   key   enctype   negotiation  purposes.   If
              allow_weak_crypto in libdefaults is false, or if des-cbc-crc  is  not  a  permitted
              enctype, then this variable has no effect.  Defaults to true.  New in release 1.11.

       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.

                 ┌─────────────────────────────────┬──────────────────────────────────┐
                 │des-cbc-crc                      │ DES cbc mode with CRC-32 (weak)  │
                 ├─────────────────────────────────┼──────────────────────────────────┤
                 │des-cbc-md4                      │ DES cbc mode with RSA-MD4 (weak) │
                 ├─────────────────────────────────┼──────────────────────────────────┤
                 │des-cbc-md5                      │ DES cbc mode with RSA-MD5 (weak) │
                 ├─────────────────────────────────┼──────────────────────────────────┤
                 │des-cbc-raw                      │ DES cbc mode raw (weak)          │
                 ├─────────────────────────────────┼──────────────────────────────────┤
                 │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                        │
                 ├─────────────────────────────────┼──────────────────────────────────┤
                 │des-hmac-sha1                    │ DES with HMAC/sha1 (weak)        │
                 ├─────────────────────────────────┼──────────────────────────────────┤
                 │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                  │                                  │
                 ├─────────────────────────────────┼──────────────────────────────────┤
                 │des                              │ The   DES  family:  des-cbc-crc, │
                 │                                 │ des-cbc-md5,   and   des-cbc-md4 │
                 │                                 │ (weak)                           │
                 ├─────────────────────────────────┼──────────────────────────────────┤
                 │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 -des"
       would be the default set of encryption types with DES 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