kdc.conf(4) File Formats kdc.conf(4)
NAME
kdc.conf - Key Distribution Center (KDC) configuration file
SYNOPSIS
/etc/krb5/kdc.conf
DESCRIPTION
The kdc.conf file contains KDC configuration information, including defaults used when issuing Kerberos tickets. This file must reside on
all KDC servers. After you make any changes to the kdc.conf file, stop and restart the krb5kdc daemon on the KDC for the changes to take
effect.
The format of the kdc.conf consists of section headings in square brackets ([]). Each section contains zero or more configuration variables
(called relations), of the form of:
relation = relation-value
or
relation-subsection = {
relation = relation-value
relation = relation-value
}
The kdc.conf file contains one of more of the following three sections:
kdcdefaults
Contains default values for overall behavior of the KDC.
realms
Contains subsections for Kerberos realms, where relation-subsection is the name of a realm. Each subsection contains relations that
define KDC properties for that particular realm, including where to find the Kerberos servers for that realm.
logging
Contains relations that determine how Kerberos programs perform logging.
The kdcdefaults Section
The following relation can be defined in the [kdcdefaults] section:
kdc_ports
This relation lists the UDP ports on which the Kerberos server should listen by default. This list is a comma-separated list of inte-
gers. Note that, if the assigned value is 0, the Kerberos server will not listen on any UDP port. If this relation is not specified,
the Kerberos server listens on port 750 and port 88.
kdc_tcp_ports
This relation lists the TCP ports on which the Kerberos server should listen by default. This list is a comma-separated list of inte-
gers. Note that, if the assigned value is 0, the Kerberos server will not listen on any TCP port. If this relation is not specified,
the Kerberos server will listen on the kdc TCP port specified in /etc/services. If this port is not found in /etc/services the Kerberos
server will default to listen on TCP port 88.
kdc_max_tcp_connections
This relation controls the maximum number of TCP connections the KDC will allow. Note, the minimum value is 10. If this relation is not
specified, the Kerberos server will allow a maximum of 30 TCP connections.
The realms Section
This section contains subsections for Kerberos realms, where relation-subsection is the name of a realm. Each subsection contains relations
that define KDC properties for that particular realm.
The following relations can be specified in each subsection:
acl_file
(string) Location of the Kerberos V5 access control list (ACL) file that kadmin uses to determine the privileges allowed to each prin-
cipal on the database. The default location is /etc/krb5/kadm5.acl.
admin_keytab
(string) Location of the keytab file that kadmin uses to authenticate to the database. The default location is /etc/krb5/kadm5.keytab.
database_name
(string) Location of the Kerberos database for this realm. The default location is /var/krb5/principal.
default_principal_expiration
(absolute time string) The default expiration date of principals created in this realm. See the Time Format section in kinit(1) for the
valid absolute time formats you can use for default_principal_expiration.
default_principal_flags
(flag string) The default attributes of principals created in this realm. Some of these flags are better to set on an individual prin-
cipal basis through the use of the attribute modifiers when using the kadmin command to create and modify principals. However, some of
these options can be applied to all principals in the realm by adding them to the list of flags associated with this relation.
A "flag string" is a list of one or more of the flags listed below preceded by a minus ("-") or a plus ("+") character, indicating that
the option that follows should be enabled or disabled.
Flags below marked with an asterisk ("*") are flags that are best applied on an individual principal basis through the kadmin or gkad-
min interface rather than as a blanket attribute to be applied to all principals.
postdateable Create postdatable tickets.
forwardable Create forwardable tickets.
tgt-based Allow TGT-based requests.
renewable Create Renewable tickets.
proxiable Create Proxiable tickets.
dup-skey Allow DUP_SKEY requests, this enables user-to-user authentication.
preauth Require the use of pre-authentication data whenever principals request TGTs.
hwauth Require the use of hardware-based pre-authentication data whenever principals request TGTs.
* allow-tickets Allow tickets to be issued for all principals.
* pwdchange Require principal's to change their password.
* service Enable or disable a service.
* pwservice Mark principals as password changing principals.
An example of default_principal_flags is shown in EXAMPLES, below.
dict_file
(string) Location of the dictionary file containing strings that are not allowed as passwords. A principal with any password policy is
not allowed to select a password in the dictionary. The default location is /var/krb5/kadm5.dict.
kadmind_port
(port number) The port that the kadmind daemon is to listen on for this realm. The assigned port for kadmind is 749.
key_stash_file
(string) Location where the master key has been stored (by kdb5_util stash). The default location is /var/krb5/.k5.realm, where realm
is the Kerberos realm.
kdc_ports
(string) The list of UDP ports that the KDC listens on for this realm. By default, the value of kdc_ports as specified in the [kdcde-
faults] section is used.
kdc_tcp_ports
(string) The list of TCP ports that the KDC listens on (in addition to the UDP ports specified by kdc_ports) for this realm. By
default, the value of kdc_tcp_ports as specified in the [kdcdefaults] section is used.
master_key_name
(string) The name of the master key.
master_key_type
(key type string) The master key's key type. This is used to determine the type of encryption that will encrypt the entries in the
principal db. des-cbc-crc, des3-cbc-sha1, arcfour-hmac-md5, arcfour-hmac-md5-exp, aes128-cts-hmac-sha1-96, and aes256-cts-hmac-sha1-96
are supported at this time (des-cbc-crc is the default). Note, if you set this to des3-cbc-sha1 all systems that receive copies of the
principal db, such as those running slave KDC's, must support des3-cbc-sha1.
max_life
(delta time string) The maximum time period for which a ticket is valid in this realm. See the Time Format section in kinit(1) for the
valid time duration formats you can use for max_life.
max_renewable_life
(delta time string) The maximum time period during which a valid ticket can be renewed in this realm. See the Time Format section in
kinit(1) for the valid time duration formats you can use for max_renewable_life.
sunw_dbprop_enable = [true | false]
Enable or disable incremental database propagation. Default is false.
sunw_dbprop_master_ulogsize = N
Specifies the maximum number of log entries available for incremental propagation to the slave KDC servers. The maximum value that this
can be is 2500 entries. Default value is 1000 entries.
sunw_dbprop_slave_poll = N[s, m, h]
Specifies how often the slave KDC polls for new updates that the master might have. Default is 2m (two minutes).
supported_enctypes
List of key/salt strings. The default key/salt combinations of principals for this realm. The key is separated from the salt by a colon
(:) or period (.). Multiple key/salt strings can be used by separating each string with a space. The salt is additional information
encoded within the key that tells what kind of key it is. Only the normal salt is supported at this time, for example, des-cbc-crc:nor-
mal. If you do not want to enable triple-DES support, you should set this tag to des-cbc-md5:normal des-cbc-crc:normal. Note that, if
this relation is not specified, the default setting is:
aes256-cts-hmac-sha1-96:normal (see note below)
aes128-cts-hmac-sha1-96:normal
des3-cbc-sha1:normal
arcfour-hmac-md5:normal
des-cbc-md5:normal
des-cbc-crc:normal
Note - The unbundled Strong Cryptographic packages must be installed for the aes256-cts-hmac-sha1-96:normal enctype to be available
for Kerberos.
The logging Section
This section indicates how Kerberos programs perform logging. The same relation can be repeated if you want to assign it multiple logging
methods. The following relations can be defined in the [logging] section:
kdc
Specifies how the KDC is to perform its logging. The default is FILE:/var/krb5/kdc.log.
admin_server
Specifies how the administration server is to perform its logging. The default is FILE:/var/krb5/kadmin.log.
default
Specifies how to perform logging in the absence of explicit specifications.
The [logging] relations can have the following values:
FILE:filename
or
FILE=filename
This value causes the entity's logging messages to go to the specified file. If the `=' form is used, the file is overwritten. If the
`:' form is used, the file is appended to.
STDERR
This value sends the entity's logging messages to its standard error stream.
CONSOLE
This value sends the entity's logging messages to the console, if the system supports it.
DEVICE=devicename
This sends the entity's logging messages to the specified device.
SYSLOG[:severity[:facility]]
This sends the entity's logging messages to the system log.
The severity argument specifies the default severity of system log messages. This default can be any of the following severities sup-
ported by the syslog(3C) call, minus the LOG_ prefix: LOG_EMERG, LOG_ALERT, LOG_CRIT, LOG_ERR, LOG_WARNING, LOG_NOTICE, LOG_INFO, and
LOG_DEBUG. For example, a value of CRIT would specify LOG_CRIT severity.
The facility argument specifies the facility under which the messages are logged. This can be any of the following facilities supported
by the syslog(3C) call minus the LOG_ prefix: LOG_KERN, LOG_USER, LOG_MAIL, LOG_DAEMON, LOG_AUTH, LOG_LPR, LOG_NEWS, LOG_UUCP,
LOG_CRON, and LOG_LOCAL0 through LOG_LOCAL7.
If no severity is specified, the default is ERR. If no facility is specified, the default is AUTH.
In the following example, the logging messages from the KDC go to the console and to the system log under the facility LOG_DAEMON with
default severity of LOG_INFO; the logging messages from the administration server are appended to the /var/krb5/kadmin.log file and
sent to the /dev/tty04 device.
[logging]
kdc = CONSOLE
kdc = SYSLOG:INFO:DAEMON
admin_server = FILE:/export/logging/kadmin.log
admin_server = DEVICE=/dev/tty04
EXAMPLES
Example 1: Sample kdc.conf File
The following is an example of a kdc.conf file:
[kdcdefaults]
kdc_ports = 88
[realms]
ATHENA.MIT.EDU = {
kadmind_port = 749
max_life = 10h 0m 0s
max_renewable_life = 7d 0h 0m 0s
default_principal_flags = +preauth,+forwardable,-postdateable
master_key_type = des-cbc-crc
supported_enctypes = des-cbc-crc:normal
}
[logging]
kdc = FILE:/export/logging/kdc.log
admin_server = FILE:/export/logging/kadmin.log
FILES
/etc/krb5/kadm5.acl
List of principals and their kadmin administrative privileges.
/etc/krb5/kadm5.keytab
Keytab for kadmin/admin Principal.
/var/krb5/principal
Kerberos principal database.
/var/krb5/principal.ulog
The update log file for incremental propagation.
/var/krb5/kadm5.dict
Dictionary of strings explicitly disallowed as passwords.
/var/krb5/kdc.log
KDC logging file.
/var/krb5/kadmin.log
Kerberos administration server logging file.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Availability |SUNWkdcu |
+-----------------------------+-----------------------------+
|Interface Stability |Evolving |
+-----------------------------+-----------------------------+
SEE ALSO
kpasswd(1), gkadmin(1M), kadmind(1M), kadmin.local(1M), kdb5_util(1M), kpropd(1M), syslog(3C), kadm5.acl(4), attributes(5), SEAM(5)
SunOS 5.10 16 Jun 2004 kdc.conf(4)