The kdc.conf file contains KDC configuration information, including defaults used when issuing Kerberos tickets.  Normally, you should install your kdc.conf file in the directory ROOTDIR/var/krb5kdc.  You can override the default location by setting the environment variable KRB5_KDC_PROFILE.

The kdc.conf file is set up in the same format as the krb5.conf file.  (see krb5.conf.)  The kdc.conf file may contain any or all of the following three sections:

kdcdefaults
     Contains default values for overall behavior of the KDC.

realms
     Contains subsections keyed by Kerberos realm names.  Each subsection describes realm-specific information, including where to find the Kerberos servers for that realm.

logging
     Contains relations which determine how Kerberos programs are to perform logging.