MIT Kerberos Documentation



kpropd [-r realm] [-A admin_server] [-a acl_file] [-f replica_dumpfile] [-F principal_database] [-p kdb5_util_prog] [-P port] [–pid-file=pid_file] [-D] [-d] [-s keytab_file]


The kpropd command runs on the replica KDC server. It listens for update requests made by the kprop program. If incremental propagation is enabled, it periodically requests incremental updates from the primary KDC.

When the replica receives a kprop request from the primary, kpropd accepts the dumped KDC database and places it in a file, and then runs kdb5_util to load the dumped database into the active database which is used by krb5kdc. This allows the primary Kerberos server to use kprop to propagate its database to the replica servers. Upon a successful download of the KDC database file, the replica Kerberos server will have an up-to-date KDC database.

Where incremental propagation is not used, kpropd is commonly invoked out of inetd(8) as a nowait service. This is done by adding a line to the /etc/inetd.conf file which looks like this:

kprop  stream  tcp  nowait  root  /usr/local/sbin/kpropd  kpropd

kpropd can also run as a standalone daemon, backgrounding itself and waiting for connections on port 754 (or the port specified with the -P option if given). Standalone mode is required for incremental propagation. Starting in release 1.11, kpropd automatically detects whether it was run from inetd and runs in standalone mode if it is not. Prior to release 1.11, the -S option is required to run kpropd in standalone mode; this option is now accepted for backward compatibility but does nothing.

Incremental propagation may be enabled with the iprop_enable variable in kdc.conf. If incremental propagation is enabled, the replica periodically polls the primary KDC for updates, at an interval determined by the iprop_replica_poll variable. If the replica receives updates, kpropd updates its log file with any updates from the primary. kproplog can be used to view a summary of the update entry log on the replica KDC. If incremental propagation is enabled, the principal kiprop/replicahostname@REALM (where replicahostname is the name of the replica KDC host, and REALM is the name of the Kerberos realm) must be present in the replica’s keytab file.

kproplog can be used to force full replication when iprop is enabled.


-r realm
Specifies the realm of the primary server.
-A admin_server
Specifies the server to be contacted for incremental updates; by default, the primary admin server is contacted.
-f file
Specifies the filename where the dumped principal database file is to be stored; by default the dumped database file is LOCALSTATEDIR/krb5kdc/from_master.
-F kerberos_db
Path to the Kerberos database file, if not the default.
Allows the user to specify the pathname to the kdb5_util program; by default the pathname used is SBINDIR/kdb5_util.
In this mode, kpropd will not detach itself from the current job and run in the background. Instead, it will run in the foreground.
Turn on debug mode. kpropd will print out debugging messages during the database propogation and will run in the foreground (implies -D).
Allow for an alternate port number for kpropd to listen on. This is only useful in combination with the -S option.
-a acl_file
Allows the user to specify the path to the kpropd.acl file; by default the path used is LOCALSTATEDIR/krb5kdc/kpropd.acl.
In standalone mode, write the process ID of the daemon into pid_file.
-s keytab_file
Path to a keytab to use for acquiring acceptor credentials.
-x db_args
Database-specific arguments. See Database Options in kadmin for supported arguments.


Access file for kpropd; the default location is /usr/local/var/krb5kdc/kpropd.acl. Each entry is a line containing the principal of a host from which the local machine will allow Kerberos database propagation via kprop.


See kerberos for a description of Kerberos environment variables.


kprop, kdb5_util, krb5kdc, kerberos, inetd(8)