MIT Kerberos Documentation


kpropd

SYNOPSIS

kpropd [-r realm] [-a acl_file] [-f slave_dumpfile] [-F principal_database] [-p kdb5_util_prog] [-P port] [-d] [-S]

DESCRIPTION

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

When the slave receives a kprop request from the master, 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 master Kerberos server to use kprop to propagate its database to the slave servers. Upon a successful download of the KDC database file, the slave Kerberos server will have an up-to-date KDC database.

Normally, kpropd is invoked out of inetd(8). 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 by specifying the -S option. This is done for debugging purposes, or if for some reason the system administrator just doesn’t want to run it out of inetd(8).

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

OPTIONS

-r realm
Specifies the realm of the master server.
-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.
-p
Allows the user to specify the pathname to the kdb5_util program; by default the pathname used is SBINDIR/kdb5_util.
-S
Turn on standalone mode. Normally, kpropd is invoked out of inetd(8) so it expects a network connection to be passed to it from inetd(8). If the -S option is specified, kpropd will put itself into the background, and wait for connections on port 754 (or the port specified with the -P option if given).
-d
Turn on debug mode. In this mode, if the -S option is selected, kpropd will not detach itself from the current job and run in the background. Instead, it will run in the foreground and print out debugging messages during the database propagation.
-P
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.

ENVIRONMENT

kpropd uses the following environment variables:

  • KRB5_CONFIG
  • KRB5_KDC_PROFILE

FILES

kpropd.acl
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 ALSO

kprop, kdb5_util, krb5kdc, inetd(8)