KRB5.CONF(5)                  File Formats Manual                 KRB5.CONF(5)

     /etc/krb5.conf — configuration file for Kerberos 5

     The /etc/krb5.conf file specifies several configuration parameters for
     the Kerberos 5 library, as well as for some programs.

     The file consists of one or more sections, containing a number of
     bindings. The value of each binding can be either a string or a list of
     other bindings. The grammar looks like:

                   /* empty */

                   section sections

                   '[' section_name ']' bindings


                   binding bindings

                   name '=' STRING
                   name '=' '{' bindings '}'


     STRINGs consists of one or more non-white space characters.  Currently
     recognised sections and bindings are:

                Specifies the default values to be used for Kerberos
                applications.  You can specify defaults per application,
                realm, or a combination of these.  The preference order is:
                1.   application realm option
                2.   application option
                3.   realm option
                4.   option

                The supported options are:

                      forwardable = boolean
                           When obtaining initial credentials, make the
                           credentials forwardable.

                      proxiable = boolean
                           When obtaining initial credentials, make the
                           credentials proxiable.

                      no-addresses = boolean
                           When obtaining initial credentials, request them
                           for an empty set of addresses, making the tickets
                           valid from any address.

                      ticket_lifetime = time
                           Default ticket lifetime.

                      renew_lifetime = time
                           Default renewable ticket lifetime.


                      default_realm = REALM
                           Default realm to use, this is also known as your
                           “local realm”.  The default is the result of
                           krb5_get_host_realm(local hostname).

                      clockskew = time
                           Maximum time differential (in seconds) allowed when
                           comparing times. Default is 300 seconds (five

                      kdc_timeout = time
                           Maximum time to wait for a reply from the kdc,
                           default is 3 seconds.


                           These are decribed in the
                           krb5_425_conv_principal(3) manual page.

                      capath = {

                                 destination-realm = next-hop-realm

                           Normally, all requests to realms different from the
                           one of the current client are sent to this KDC to
                           get cross-realm tickets.  If this KDC does not have
                           a cross-realm key with the desired realm and the
                           hierarchical path to that realm does not work, a
                           path can be configured using this directive.  The
                           text shown above instructs the KDC to try to obtain
                           a cross-realm ticket to next-hop-realm when the
                           desired realm is destination-realm.  This
                           configuration should preferably be done on the KDC
                           where it will help all its clients but can also be
                           done on the client itself.


                      default_etypes = etypes...
                           A list of default etypes to use.

                      default_etypes_des = etypes...
                           A list of default etypes to use when requesting a
                           DES credential.

                      default_keytab_name = keytab
                           The keytab to use if none other is specified,
                           default is “FILE:/etc/krb5.keytab”.

                      kdc_timesync = boolean
                           Try to keep track of the time differential between
                           the local machine and the KDC, and then compensate
                           for that when issuing requests.

                      max_retries = number
                           The max number of times to try to contact each KDC.

                      ticket_lifetime = time
                           Default ticket lifetime.

                      renew_lifetime = time
                           Default renewable ticket lifetime.

                      forwardable = boolean
                           When obtaining initial credentials, make the
                           credentials forwardable.  This option is also valid
                           in the [realms] section.

                      proxiable = boolean
                           When obtaining initial credentials, make the
                           credentials proxiable.  This option is also valid
                           in the [realms] section.

                      verify_ap_req_nofail = boolean
                           Enable to make a failure to verify obtained
                           credentials non-fatal. This can be useful if there
                           is no keytab on a host.

                      warn_pwexpire = time
                           How soon to warn for expiring password. Default is
                           seven days.

                      http_proxy = proxy-spec
                           A HTTP-proxy to use when talking to the KDC via

                      dns_proxy = proxy-spec
                           Enable using DNS via HTTP.

                      extra_addresses = address...
                           A list of addresses to get tickets for along with
                           all local addresses.

                      time_format = string
                           How to print time strings in logs, this string is
                           passed to strftime(3).

                      date_format = string
                           How to print date strings in logs, this string is
                           passed to strftime(3).

                      log_utc = boolean
                           Write log-entries using UTC instead of your local
                           time zone.

                      srv_lookup = boolean
                           Use DNS SRV records to lookup realm configuration

                      scan_interfaces = boolean
                           Scan all network interfaces for addresses, as
                           opposed to simply using the address associated with
                           the system's host name.

                      fcache_version = int
                           Use file credential cache format version specified.

                      krb4_get_tickets = boolean
                           Also get Kerberos 4 tickets in kinit, login, and
                           other programs.  This option is also valid in the
                           [realms] section.

                This is a list of mappings from DNS domain to Kerberos realm.
                Each binding in this section looks like:

                      domain = realm

                The domain can be either a full name of a host or a trailing
                component, in the latter case the domain-string should start
                with a perid.


                      REALM = {

                                 kdc = host[:port]
                                      Specifies a list of kdcs for this realm.
                                      If the optional port is absent, the
                                      default value for the “kerberos/udp”
                                      service will be used.  The kdcs will be
                                      used in the order that they are

                                 admin_server = host[:port]
                                      Specifies the admin server for this
                                      realm, where all the modifications to
                                      the database are perfomed.

                                 kpasswd_server = host[:port]
                                      Points to the server where all the
                                      password changes are perfomed.  If there
                                      is no such entry, the kpasswd port on
                                      the admin_server host will be tried.

                                 krb524_server = Host[:port]
                                      Points to the server that does 524
                                      conversions.  If it is not mentioned,
                                      the krb524 port on the kdcs will be



                                      See krb5_425_conv_principal(3).



                      entity = destination
                           Specifies that entity should use the specified
                           destination for logging. See the krb5_openlog(3)
                           manual page for a list of defined destinations.


                      database = {

                                 dbname = DATABASENAME
                                      use this database for this realm.

                                 realm = REALM
                                      specifies the realm that will be stored
                                      in this database.

                                 mkey_file = FILENAME
                                      use this keytab file for the master key
                                      of this database.  If not specified
                                      DATABASENAME.mkey will be used.

                                 acl_file = PA FILENAME
                                      use this file for the ACL list of this

                                 log_file = FILENAME
                                      use this file as the log of changes
                                      performed to the database.  This file is
                                      used by ipropd-master for propagating
                                      changes to slaves.


                      max-request = SIZE
                           Maximum size of a kdc request.

                      require-preauth = BOOL
                           If set pre-authentication is required. Since krb4
                           requests are not pre-authenticated they will be

                      ports = list of ports
                           list of ports the kdc should listen to.

                      addresses = list of interfaces
                           list of addresses the kdc should bind to.

                      enable-kerberos4 = BOOL
                           turn on kerberos4 support.

                      v4-realm = REALM
                           to what realm v4 requests should be mapped.

                      enable-524 = BOOL
                           should the Kerberos 524 converting facility be
                           turned on. Default is same as enable-kerberos4.

                      enable-http = BOOL
                           should the kdc answer kdc-requests over http.

                      enable-kaserver = BOOL
                           if this kdc should emulate the AFS kaserver.

                      check-ticket-addresses = BOOL
                           verify the addresses in the tickets used in tgs

                      allow-null-ticket-addresses = BOOL
                           allow addresses-less tickets.

                      allow-anonymous = BOOL
                           if the kdc is allowed to hand out anonymous

                      encode_as_rep_as_tgs_rep = BOOL
                           encode as-rep as tgs-rep tobe compatible with
                           mistakes older DCE secd did.

                      kdc_warn_pwexpire = TIME
                           the time before expiration that the user should be
                           warned that her password is about to expire.

                      logging = Logging
                           What type of logging the kdc should use, see also


                      require-preauth = BOOL
                           If pre-authentication is required to talk to the
                           kadmin server.

                      default_keys = keytypes...
                           for each entry in default_keys try to parse it as a
                           sequence of etype:salttype:salt syntax of this if
                           something like:


                           if etype is omitted it means everything, and if
                           string is omitted is means the default string (for
                           that principal). Additional special values of
                           keyttypes are:

                                 v5   The kerberos 5 salt pw-salt

                                 v4   The kerberos 4 type des:pw-salt:

                      use_v4_salt = BOOL
                           When true, this is the same as

                           default_keys = des3:pw-salt v4

                           and is only left for backwards compatability.

     KRB5_CONFIG points to the configuration file to read.

                   default_realm = FOO.SE
                   .foo.se = FOO.SE
                   .bar.se = FOO.SE
                   FOO.SE = {
                           kdc = kerberos.foo.se
                           v4_name_convert = {
                                   rcmd = host
                           v4_instance_convert = {
                                   xyz = xyz.bar.se
                           default_domain = foo.se
                   kdc = FILE:/var/heimdal/kdc.log
                   kdc = SYSLOG:INFO
                   default = SYSLOG:INFO:USER

     Since /etc/krb5.conf is read and parsed by the krb5 library, there is not
     a lot of opportunities for programs to report parsing errors in any
     useful format.  To help overcome this problem, there is a program
     verify_krb5_conf that reads /etc/krb5.conf and tries to emit useful
     diagnostics from parsing errors.  Note that this program does not have
     any way of knowing what options are actually used and thus cannot warn
     about unknown or misspelled ones.

     kinit(1), krb5_425_conv_principal(3), krb5_openlog(3), strftime(3),

HEIMDAL                         April 11, 1999                         HEIMDAL