NAME

     kdc — Kerberos 5 server

SYNOPSIS

     kdc [-c file | --config-file=file] [-p | --no-require-preauth] [--max-request=size]
         [-H | --enable-http] [--no-524] [--kerberos4] [--kerberos4-cross-realm] [-r string |
         --v4-realm=string] [-P portspec | --ports=portspec] [--detach] [--disable-des]
         [--addresses=list of addresses]

DESCRIPTION

     kdc serves requests for tickets.  When it starts, it first checks the flags passed, any
     options that are not specified with a command line flag are taken from a config file, or
     from a default compiled-in value.

     Options supported:

     -c file, --config-file=file
             Specifies the location of the config file, the default is /etc/heimdal-kdc/kdc.conf.
             This is the only value that can't be specified in the config file.

     -p, --no-require-preauth
             Turn off the requirement for pre-autentication in the initial AS-REQ for all
             principals.  The use of pre-authentication makes it more difficult to do offline
             password attacks.  You might want to turn it off if you have clients that don't
             support pre-authentication.  Since the version 4 protocol doesn't support any pre-
             authentication, serving version 4 clients is just about the same as not requiring
             pre-athentication.  The default is to require pre-authentication.  Adding the
             require-preauth per principal is a more flexible way of handling this.

     --max-request=size
             Gives an upper limit on the size of the requests that the kdc is willing to handle.

     -H, --enable-http
             Makes the kdc listen on port 80 and handle requests encapsulated in HTTP.

     --no-524
             don't respond to 524 requests

     --kerberos4
             respond to Kerberos 4 requests

     --kerberos4-cross-realm
             respond to Kerberos 4 requests from foreign realms.  This is a known security hole
             and should not be enabled unless you understand the consequences and are willing to
             live with them.

     -r string, --v4-realm=string
             What realm this server should act as when dealing with version 4 requests.  The
             database can contain any number of realms, but since the version 4 protocol doesn't
             contain a realm for the server, it must be explicitly specified.  The default is
             whatever is returned by krb_get_lrealm().  This option is only available if the KDC
             has been compiled with version 4 support.

     -P portspec, --ports=portspec
             Specifies the set of ports the KDC should listen on.  It is given as a white-space
             separated list of services or port numbers.

     --addresses=list of addresses
             The list of addresses to listen for requests on.  By default, the kdc will listen on
             all the locally configured addresses.  If only a subset is desired, or the automatic
             detection fails, this option might be used.

     --detach
             detach from pty and run as a daemon.

     --disable-des
             disable all des encryption types, makes the kdc not use them.

     All activities are logged to one or more destinations, see krb5.conf(5), and
     krb5_openlog(3).  The entity used for logging is kdc.

CONFIGURATION FILE

     The configuration file has the same syntax as krb5.conf(5), but will be read before
     /etc/krb5.conf, so it may override settings found there.  Options specific to the KDC only
     are found in the “[kdc]” section.  All the command-line options can preferably be added in
     the configuration file.  The only difference is the pre-authentication flag, which has to be
     specified as:

           require-preauth = no

     (in fact you can specify the option as --require-preauth=no).

     And there are some configuration options which do not have command-line equivalents:

           enable-digest = boolean
                turn on support for digest processing in the KDC.  The default is FALSE.

           check-ticket-addresses = boolean
                Check the addresses in the ticket when processing TGS requests.  The default is
                TRUE.

           allow-null-ticket-addresses = boolean
                Permit tickets with no addresses.  This option is only relevant when check-
                ticket-addresses is TRUE.

           allow-anonymous = boolean
                Permit anonymous tickets with no addresses.

           max-kdc-datagram-reply-length = number
                Maximum packet size the UDP rely that the KDC will transmit, instead the KDC
                sends back a reply telling the client to use TCP instead.

           transited-policy = always-check | allow-per-principal | always-honour-request
                This controls how KDC requests with the disable-transited-check flag are handled.
                It can be one of:

                      always-check
                           Always check transited encoding, this is the default.

                      allow-per-principal
                           Currently this is identical to always-check.  In a future release, it
                           will be possible to mark a principal as able to handle unchecked
                           requests.

                      always-honour-request
                           Always do what the client asked.  In a future release, it will be
                           possible to force a check per principal.

           encode_as_rep_as_tgs_rep = boolean
                Encode AS-Rep as TGS-Rep to be bug-compatible with old DCE code.  The Heimdal
                clients allow both.

           kdc_warn_pwexpire = time
                How long before password/principal expiration the KDC should start sending out
                warning messages.

     The configuration file is only read when the kdc is started.  If changes made to the
     configuration file are to take effect, the kdc needs to be restarted.

     An example of a config file:

           [kdc]
                   require-preauth = no
                   v4-realm = FOO.SE

BUGS

     If the machine running the KDC has new addresses added to it, the KDC will have to be
     restarted to listen to them.  The reason it doesn't just listen to wildcarded (like
     INADDR_ANY) addresses, is that the replies has to come from the same address they were sent
     to, and most OS:es doesn't pass this information to the application.  If your normal mode of
     operation require that you add and remove addresses, the best option is probably to listen
     to a wildcarded TCP socket, and make sure your clients use TCP to connect.  For instance,
     this will listen to IPv4 TCP port 88 only:

           kdc --addresses=0.0.0.0 --ports="88/tcp"

     There should be a way to specify protocol, port, and address triplets, not just addresses
     and protocol, port tuples.

SEE ALSO

     kinit(1), krb5.conf(5)