KDC.CONF(5)KDC.CONF(5)NAMEkdc.conf - Kerberos V5 KDC configuration file
DESCRIPTIONkdc.conf specifies per-realm configuration data to be used by the Ker‐
beros V5 Authentication Service and Key Distribution Center (AS/KDC).
This includes database, key and per-realm defaults.
The kdc.conf file uses the same format as the krb5.conf file. For a
basic description of the syntax, please refer to the krb5.conf descrip‐
tion.
The following sections are currently used in the kdc.conf file:
[kdcdefaults]
Contains parameters which control the overall behaviour of the
KDC.
[realms]
Contains subsections keyed by Kerberos realm names which
describe per-realm KDC parameters.
KDCDEFAULTS SECTION
The following relations are defined in the [kdcdefaults] section:
kdc_ports
This relation lists the ports which the Kerberos server should
listen on, by default. This list is a comma separated list of
integers. If this relation is not specified, the compiled-in
default is usually port 88 and port 750.
v4_mode
This string specifies how the KDC should respond to Kerberos IV
packets. Valid values for this relation are the same as the
valid arguments to the -4 flag to krb5kdc. If this relation is
not specified, the compiled-in default of none is used.
REALMS SECTION
Each tag in the [realms] section of the file names a Kerberos realm.
The value of the tag is a subsection where the relations in that sub‐
section define KDC parameters for that particular realm.
For each realm, the following tags may be specified in the [realms]
subsection:
acl_file
This string specifies the location of the access control list
(acl) file that kadmin uses to determine which principals are
allowed which permissions on the database. The default value is
/var/lib/kerberos/krb5kdc/kadm5.acl.
admin_keytab
This string Specifies the location of the keytab file that kad‐
min uses to authenticate to the database. The default value is
/var/lib/kerberos/krb5kdc/kadm5.keytab.
database_name
This string specifies the location of the Kerberos database for
this realm.
default_principal_expiration
This absolute time string specifies the default expiration date
of principals created in this realm.
default_principal_flags
This flag string specifies the default attributes of principals
created in this realm. The format for the string is a comma-
separated list of flags, with '+' before each flag to be enabled
and '-' before each flag to be disabled. The default is for
postdateable, forwardable, tgt-based, renewable, proxiable, dup-
skey, allow-tickets, and service to be enabled, and all others
to be disabled.
There are a number of possible flags:
postdateable
Enabling this flag allows the principal to obtain post‐
dateable tickets.
forwardable
Enabling this flag allows the principal to obtain for‐
wardable tickets.
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.
renewable
Enabling this flag allows the principal to obtain renew‐
able tickets.
proxiable
Enabling this flag allows the principal to obtain proxy
tickets.
dup-skey
Enabling this flag allows the principal to obtain a ses‐
sion key for another user, permitting user-to-user
authentication for this principal.
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.
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 ticket set.
hwauth If this flag is enabled, then the principal is required
to preauthenticate using a hardware device before receiv‐
ing any tickets.
pwchange
Enabling this flag forces a password change for this
principal.
service
Enabling this flag allows the the KDC to issue service
tickets 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, the user has to get tickets for that principal
to be able to change it without going through the normal
password authentication.
dict_file
This string location of the dictionary file containing strings
that are not allowed as passwords. If this tag is not set or if
there is no policy assigned to the principal, then no check will
be done.
kadmind_port
This port number specifies the port on which the kadmind daemon
is to listen for this realm.
kpasswd_port
This port number specifies the port on which the kadmind daemon
is to listen for this realm.
key_stash_file
This string specifies the location where the master key has been
stored with kdb5_stash.
kdc_ports
This string specifies the list of ports that the KDC is to lis‐
ten to for this realm. By default, the value of kdc_ports as
specified in the [kdcdefaults] section is used.
master_key_name
This string specifies the name of the principal associated with
the master key. The default value is K/M.
master_key_type
This key type string represents the master key's key type.
max_life
This delta time string specifes the maximum time period that a
ticket may be valid for in this realm.
max_renewable_life
This delta time string specifies the maximum time period that a
ticket may be renewed for in this realm.
supported_enctypes
list of key:salt strings that specifies the default key/salt
combinations of principals for this realm
kdc_supported_enctypes
specifies the permitted key-salt combinations of principals for
this realm
reject_bad_transit
this boolean specifies whether or not the list of transited
realms for cross-realm tickets should be checked against the
transit path computed from the realm names and the [capaths]
section of its krb5.conf file
FILES
/var/lib/kerberos/krb5kdc/kdc.conf
SEE ALSOkrb5.conf(5), krb5kdc(8)KDC.CONF(5)
