KRB5.CONF(5)               UNIX Programmer's Manual               KRB5.CONF(5)


     krb5.conf - configuration file for Kerberos 5



     The 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 bind-
     ings.  The value of each binding can be either a string or a list of oth-
     er bindings.  The grammar looks like:

                   /* empty */

                   section sections

                   '[' section_name ']' bindings


                   binding bindings

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


     STRINGs consists of one or more non-whitespace characters.

     STRINGs that are specified later in this man-page uses the following no-

                values can be either yes/true or no/false.

                values can be a list of year, month, day, hour, min, second.
                Example: 1 month 2 days 30 min.

                valid encryption types are: des-cbc-crc, des-cbc-md4, des-cbc-
                md5, des3-cbc-sha1, arcfour-hmac-md5, aes128-cts-hmac-sha1-96,
                and aes256-cts-hmac-sha1-96 .

                an address can be either a IPv4 or a IPv6 address.

     Currently recognised sections and bindings are:

                Specifies the default values to be used for Kerberos applica-
                tions.  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 cre-
                           dentials forwardable.

                      proxiable = boolean
                           When obtaining initial credentials, make the cre-
                           dentials 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.

                      encrypt = boolean
                           Use encryption, when available.

                      forward = boolean
                           Forward credentials to remote host (for rsh(1),
                           telnet(1),  etc).


                      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 min-

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


                           These are described in the krb5_425_conv_princi-
                           pal(3) manual page.

                      capath = {

                                 destination-realm = next-hop-realm



                           This is deprecated, see the capaths section below.

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

                      default_etypes_des = etypes ...
                           A list of default encryption types to use when re-
                           questing a DES credential.

                      default_keytab_name = keytab
                           The keytab to use if no other is specified, default
                           is ``FILE:/etc/krb5.keytab''.

                      dns_lookup_kdc = boolean
                           Use DNS SRV records to lookup KDC services loca-

                      dns_lookup_realm = boolean
                           Use DNS TXT records to lookup domain to realm map-

                      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 cre-
                           dentials forwardable.  This option is also valid in
                           the [realms] section.

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

                      verify_ap_req_nofail = boolean
                           If enabled, failure to verify credentials against a
                           local key is a fatal error.  The application has to
                           be able to read the corresponding service key for
                           this to work.  Some applications, like su(1),  en-
                           able this option unconditionally.

                      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.

                      scan_interfaces = boolean
                           Scan all network interfaces for addresses, as op-
                           posed 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.

                      fcc-mit-ticketflags = boolean
                           Use MIT compatible format for file credential
                           cache.  It's the field ticketflags that is stored
                           in reverse bit order for older than Heimdal 0.7.
                           Setting this flag to TRUE make it store the MIT
                           way, this is default for Heimdal 0.7.

                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 period.  The realm may be the token `dns_locate', in
                which case the actual realm will be determined using DNS (in-
                dependently of the setting of the `dns_lookup_realm' option).


                      REALM = {

                                 kdc = [service/]host[:port]
                                      Specifies a list of kdcs for this realm.
                                      If the optional port is absent, the de-
                                      fault value for the ``kerberos/udp''
                                      ``kerberos/tcp'', and ``http/tcp'' port
                                      (depending on service) will be used.
                                      The kdcs will be used in the order that
                                      they are specified.

                                      The optional service specifies over what
                                      medium the kdc should be contacted.
                                      Possible services are ``udp'', ``tcp'',
                                      and ``http''. Http can also be written
                                      as ``http://''. Default service is

                                      ``udp'' and ``tcp''.

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

                                 kpasswd_server = host[:port]
                                      Points to the server where all the pass-
                                      word changes are performed.  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 con-
                                      versions.  If it is not mentioned, the
                                      krb524 port on the kdcs will be tried.



                                      See krb5_425_conv_principal(3).

                                      a boolan variable that defaults to
                                      false.  Old DCE secd (pre 1.1) might
                                      need this to be true.



                      client-realm = {

                                 server-realm = hop-realm ...
                                      This serves two purposes. First the
                                      first listed hop-realm tells a client
                                      which realm it should contact in order
                                      to ultimately obtain credentials for a
                                      service in the server-realm. Secondly,
                                      it tells the KDC (and other servers)
                                      which realms are allowed in a multi-hop
                                      traversal from client-realm to server-
                                      realm. Except for the client case, the
                                      order of the realms are not important.



                      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 per-
                                      formed 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 re-

                      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 Kerberos 4 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 re-

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

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

                      encode_as_rep_as_tgs_rep = BOOL
                           Encode as-rep as tgs-rep tobe compatible with mis-
                           takes 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

                      use_2b = principal list
                           List of principals to use AFS 2b tokens for.


                      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 it means the default salt string
                           (for that principal and encryption type).  Addi-
                           tional special values of keytypes are:

                                 v5   The Kerberos 5 salt pw-salt

                                 v4   The Kerberos 4 salt 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 compatibility.


     KRB5_CONFIG points to the configuration file to read.


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


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


     Since 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 krb5.conf and tries to emit useful diagnos-
     tics from parsing errors.  Note that this program does not have any way
     of knowing what options are actually used and thus cannot warn about un-
     known or misspelled ones.


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

 HEIMDAL                         March 9, 2004                               8

Man(1) output converted with man2html