KRB5KDC(8) MIT Kerberos KRB5KDC(8)NAMEkrb5kdc - Kerberos V5 KDC
SYNOPSISkrb5kdc [-x db_args] [-d dbname] [-k keytype] [-M mkeyname] [-p port‐
num] [-m] [-r realm] [-n] [-w numworkers] [-P pid_file] [-T time_off‐
DESCRIPTIONkrb5kdc is the Kerberos version 5 Authentication Service and Key Dis‐
tribution Center (AS/KDC).
The -r realm option specifies the realm for which the server should
The -d dbname option specifies the name under which the principal data‐
base can be found. This option does not apply to the LDAP database.
The -k keytype option specifies the key type of the master key to be
entered manually as a password when -m is given; the default is
The -M mkeyname option specifies the principal name for the master key
in the database (usually K/M in the KDC's realm).
The -m option specifies that the master database password should be
fetched from the keyboard rather than from a stash file.
The -n option specifies that the KDC does not put itself in the back‐
ground and does not disassociate itself from the terminal. In normal
operation, you should always allow the KDC to place itself in the back‐
The -P pid_file option tells the KDC to write its PID into pid_file
after it starts up. This can be used to identify whether the KDC is
still running and to allow init scripts to stop the correct process.
The -p portnum option specifies the default UDP port numbers which the
KDC should listen on for Kerberos version 5 requests, as a comma-sepa‐
rated list. This value overrides the UDP port numbers specified in the
kdcdefaults section of kdc.conf(5), but may be overridden by realm-spe‐
cific values. If no value is given from any source, the default ports
are 88 and 750.
The -w numworkers option tells the KDC to fork numworkers processes to
listen to the KDC ports and process requests in parallel. The top
level KDC process (whose pid is recorded in the pid file if the -P
option is also given) acts as a supervisor. The supervisor will relay
SIGHUP signals to the worker subprocesses, and will terminate the
worker subprocess if the it is itself terminated or if any other worker
Note On operating systems which do not have pktinfo support, using
worker processes will prevent the KDC from listening for UDP
packets on network interfaces created after the KDC starts.
The -x db_args option specifies database-specific arguments. Options sup‐
ported for the LDAP database module are:-x nconns=<number_of_connections>
Specifies the number of connections to be maintained per LDAP
Specifies the LDAP server to connect to by URI.
Specifies the DN of the object used by the KDC server to bind to the
LDAP server. This object should have read and write privileges to
the realm container, the principal container, and the subtree that
is referenced by the realm.
Specifies the password for the above mentioned binddn. Using this
option may expose the password to other users on the system via the
process list; to avoid this, instead stash the password using the
stashsrvpw command of kdb5_ldap_util(8).
sets the OpenLDAP client library debug level. level is an integer
to be interpreted by the library. Debugging messages are printed to
standard error, so this option must be used with the -n option to be
useful. New in release 1.12.
The -T offset option specifies a time offset, in seconds, which the KDC will
operate under. It is intended only for testing purposes.
The KDC may service requests for multiple realms (maximum 32 realms).
The realms are listed on the command line. Per-realm options that can
be specified on the command line pertain for each realm that follows it
and are superseded by subsequent definitions of the same option.
krb5kdc-p 2001 -r REALM1 -p 2002 -r REALM2 -r REALM3
specifies that the KDC listen on port 2001 for REALM1 and on port 2002
for REALM2 and REALM3. Additionally, per-realm parameters may be spec‐
ified in the kdc.conf(5) file. The location of this file may be speci‐
fied by the KRB5_KDC_PROFILE environment variable. Per-realm parame‐
ters specified in this file take precedence over options specified on
the command line. See the kdc.conf(5) description for further details.
ENVIRONMENTkrb5kdc uses the following environment variables:
SEE ALSOkdb5_util(8), kdc.conf(5), krb5.conf(5), kdb5_ldap_util(8)AUTHOR