lib/krb5/krb5.conf.5

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.\" $Id: krb5.conf.5,v 1.35 2003/04/16 13:26:13 lha Exp $
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.Dd April 11, 1999
.Dt KRB5.CONF 5
.Os HEIMDAL
.Sh NAME
.Nm /etc/krb5.conf
.Nd configuration file for Kerberos 5
.Sh DESCRIPTION
The
.Nm
file specifies several configuration parameters for the Kerberos 5
library, as well as for some programs.
.Pp
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:
.Bd -literal -offset indent
file:
	/* empty */
	sections

sections:
	section sections
	section

section:
	'[' section_name ']' bindings

section_name:
	STRING

bindings:
	binding bindings
	binding

binding:
	name '=' STRING
	name '=' '{' bindings '}'

name:
	STRING

.Ed
.Li STRINGs
consists of one or more non-whitespace characters.
.Pp
STRINGs that are specified later in this man-page uses the following
notation.
.Bl -tag -width "xxx" -offset indent
.It boolean
values can be either yes/true or no/false.
.It time
values can be a list of year, month, day, hour, min, second.
Example: 1 month 2 days 30 min.
.It etypes
valid encryption types are: des-cbc-crc, des-cbc-md4, des-cbc-md5,
des3-cbc-sha1.
.It address
an address can be either a IPv4 or a IPv6 address.
.El
.Pp
Currently recognised sections and bindings are:
.Bl -tag -width "xxx" -offset indent
.It Li [appdefaults]
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:
.Bl -enum -compact
.It
.Va application Va realm Va option
.It
.Va application Va option
.It
.Va realm Va option
.It
.Va option
.El
.Pp
The supported options are:
.Bl -tag -width "xxx" -offset indent
.It Li forwardable = Va boolean
When obtaining initial credentials, make the credentials forwardable.
.It Li proxiable = Va boolean
When obtaining initial credentials, make the credentials proxiable.
.It Li no-addresses = Va boolean
When obtaining initial credentials, request them for an empty set of
addresses, making the tickets valid from any address.
.It Li ticket_lifetime = Va time
Default ticket lifetime.
.It Li renew_lifetime = Va time
Default renewable ticket lifetime.
.El
.It Li [libdefaults]
.Bl -tag -width "xxx" -offset indent
.It Li default_realm = Va REALM
Default realm to use, this is also known as your
.Dq local realm .
The default is the result of
.Fn krb5_get_host_realm "local hostname" .
.It Li clockskew = Va time
Maximum time differential (in seconds) allowed when comparing
times.
Default is 300 seconds (five minutes).
.It Li kdc_timeout = Va time
Maximum time to wait for a reply from the kdc, default is 3 seconds.
.It v4_name_convert
.It v4_instance_resolve
These are described in the
.Xr krb5_425_conv_principal  3
manual page.
.It Li capath = {
.Bl -tag -width "xxx" -offset indent
.It Va destination-realm Li = Va next-hop-realm
.It ...
.El
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
.Va next-hop-realm
when the desired realm is
.Va 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.
.It Li }
.It Li default_etypes = Va etypes...
A list of default encryption types to use.
.It Li default_etypes_des = Va etypes...
A list of default encryption types to use when requesting a DES credential.
.It Li default_keytab_name = Va keytab
The keytab to use if no other is specified, default is
.Dq FILE:/etc/krb5.keytab .
.It Li dns_lookup_kdc = Va boolean
Use DNS SRV records to lookup KDC services location.
.It Li dns_lookup_realm = Va boolean
Use DNS TXT records to lookup domain to realm mappings.
.It Li kdc_timesync = Va boolean
Try to keep track of the time differential between the local machine
and the KDC, and then compensate for that when issuing requests.
.It Li max_retries = Va number
The max number of times to try to contact each KDC.
.It Li ticket_lifetime = Va time
Default ticket lifetime.
.It Li renew_lifetime = Va time
Default renewable ticket lifetime.
.It Li forwardable = Va boolean
When obtaining initial credentials, make the credentials forwardable.
This option is also valid in the [realms] section.
.It Li proxiable = Va boolean
When obtaining initial credentials, make the credentials proxiable.
This option is also valid in the [realms] section.
.It Li verify_ap_req_nofail = Va 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
.Xr su 8 ,
enable this option unconditionally.
.It Li warn_pwexpire = Va time
How soon to warn for expiring password.
Default is seven days.
.It Li http_proxy = Va proxy-spec
A HTTP-proxy to use when talking to the KDC via HTTP.
.It Li dns_proxy = Va proxy-spec
Enable using DNS via HTTP.
.It Li extra_addresses = Va address...
A list of addresses to get tickets for along with all local addresses.
.It Li time_format = Va string
How to print time strings in logs, this string is passed to
.Xr strftime 3 .
.It Li date_format = Va string
How to print date strings in logs, this string is passed to
.Xr strftime 3 .
.It Li log_utc = Va boolean
Write log-entries using UTC instead of your local time zone.
.It Li scan_interfaces = Va boolean
Scan all network interfaces for addresses, as opposed to simply using
the address associated with the system's host name.
.It Li fcache_version = Va int
Use file credential cache format version specified.
.It Li krb4_get_tickets = Va boolean
Also get Kerberos 4 tickets in
.Nm kinit ,
.Nm login ,
and other programs.
This option is also valid in the [realms] section.
.El
.It Li [domain_realm]
This is a list of mappings from DNS domain to Kerberos realm.
Each binding in this section looks like:
.Pp
.Dl domain = realm
.Pp
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 (independently of the setting
of the `dns_lookup_realm' option).
.It Li [realms]
.Bl -tag -width "xxx" -offset indent
.It Va REALM Li = {
.Bl -tag -width "xxx" -offset indent
.It Li kdc = Va [service/]host[:port]
Specifies a list of kdcs for this realm.
If the optional
.Va port
is absent, the
default value for the
.Dq kerberos/udp
.Dq kerberos/tcp ,
and
.Dq http/tcp
port (depending on service) will be used.
The kdcs will be used in the order that they are specified.
.Pp
The optional
.Va service
specifies over what medium the kdc should be
contacted.
Possible services are
.Dq udp ,
.Dq tcp ,
and
.Dq http .
Http can also be written as
.Dq http:// .
Default service is
.Dq udp
and
.Dq tcp .
.It Li admin_server = Va host[:port]
Specifies the admin server for this realm, where all the modifications
to the database are performed.
.It Li kpasswd_server = Va host[:port]
Points to the server where all the password changes are performed.
If there is no such entry, the kpasswd port on the admin_server host
will be tried.
.It Li krb524_server = Va host[:port]
Points to the server that does 524 conversions.
If it is not mentioned, the krb524 port on the kdcs will be tried.
.It Li v4_instance_convert
.It Li v4_name_convert
.It Li default_domain
See
.Xr krb5_425_conv_principal 3 .
.El
.It Li }
.El
.It Li [logging]
.Bl -tag -width "xxx" -offset indent
.It Va entity Li = Va destination
Specifies that
.Va entity
should use the specified
.Li destination
for logging.
See the
.Xr krb5_openlog 3
manual page for a list of defined destinations.
.El
.It Li [kdc]
.Bl -tag -width "xxx" -offset indent
.It database Li = {
.Bl -tag -width "xxx" -offset indent
.It dbname Li = Va DATABASENAME
Use this database for this realm.
.It realm Li = Va REALM
Specifies the realm that will be stored in this database.
.It mkey_file Li = Pa FILENAME
Use this keytab file for the master key of this database.
If not specified
.Va DATABASENAME Ns .mkey
will be used.
.It acl_file Li = PA FILENAME
Use this file for the ACL list of this database.
.It log_file Li = Pa FILENAME
Use this file as the log of changes performed to the database.
This file is used by
.Nm ipropd-master
for propagating changes to slaves.
.El
.It Li }
.It max-request = Va SIZE
Maximum size of a kdc request.
.It require-preauth = Va BOOL
If set pre-authentication is required.
Since krb4 requests are not pre-authenticated they will be rejected.
.It ports = Va "list of ports"
List of ports the kdc should listen to.
.It addresses = Va "list of interfaces"
List of addresses the kdc should bind to.
.It enable-kerberos4 = Va BOOL
Turn on Kerberos 4 support.
.It v4-realm = Va REALM
To what realm v4 requests should be mapped.
.It enable-524 = Va BOOL
Should the Kerberos 524 converting facility be turned on.
Default is same as
.Va enable-kerberos4 .
.It enable-http = Va BOOL
Should the kdc answer kdc-requests over http.
.It enable-kaserver = Va BOOL
If this kdc should emulate the AFS kaserver.
.It check-ticket-addresses = Va BOOL
verify the addresses in the tickets used in tgs requests.
.\" XXX
.It allow-null-ticket-addresses = Va BOOL
Allow addresses-less tickets.
.\" XXX
.It allow-anonymous = Va BOOL
If the kdc is allowed to hand out anonymous tickets.
.It encode_as_rep_as_tgs_rep = Va BOOL
Encode as-rep as tgs-rep tobe compatible with mistakes older DCE secd did.
.\" XXX
.It kdc_warn_pwexpire = Va TIME
The time before expiration that the user should be warned that her
password is about to expire.
.It logging = Va Logging
What type of logging the kdc should use, see also [logging]/kdc.
.It use_2b = Va principal list
List of principals to use AFS 2b tokens for.
.El
.It Li [kadmin]
.Bl -tag -width "xxx" -offset indent
.It require-preauth = Va BOOL
If pre-authentication is required to talk to the kadmin server.
.It default_keys = Va keytypes...
for each entry in
.Va default_keys
try to parse it as a sequence of
.Va etype:salttype:salt
syntax of this if something like:
.Pp
[(des|des3|etype):](pw-salt|afs3-salt)[:string]
.Pp
If
.Ar etype
is omitted it means everything, and if string is omitted it means the
default salt string (for that principal and encryption type).
Additional special values of keytypes are:
.Bl -tag -width "xxx" -offset indent
.It v5
The Kerberos 5 salt
.Va pw-salt
.It v4
The Kerberos 4 salt
.Va des:pw-salt:
.El
.It use_v4_salt = Va BOOL
When true, this is the same as
.Pp
.Va default_keys = Va des3:pw-salt Va v4
.Pp
and is only left for backwards compatibility.
.El
.El
.Sh ENVIRONMENT
.Ev KRB5_CONFIG
points to the configuration file to read.
.Sh EXAMPLE
.Bd -literal -offset indent
[libdefaults]
	default_realm = FOO.SE
[domain_realm]
	.foo.se = FOO.SE
	.bar.se = FOO.SE
[realms]
	FOO.SE = {
		kdc = kerberos.foo.se
		v4_name_convert = {
			rcmd = host
		}
		v4_instance_convert = {
			xyz = xyz.bar.se
		}
		default_domain = foo.se
	}
[logging]
	kdc = FILE:/var/heimdal/kdc.log
	kdc = SYSLOG:INFO
	default = SYSLOG:INFO:USER
.Ed
.Sh DIAGNOSTICS
Since
.Nm
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
.Nm verify_krb5_conf
that reads
.Nm
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.
.Sh SEE ALSO
.Xr kinit 1 ,
.Xr krb5_425_conv_principal 3 ,
.Xr krb5_openlog 3 ,
.Xr strftime 3 ,
.Xr verify_krb5_conf 8