NAME

       kdc — Kerberos 5 server

SYNOPSIS

       kdc  [-c file | --config-file=file] [-p | --no-require-preauth] [--max-request=size] [-H | --enable-http]
           [-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.

       -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)

HEIMDAL                                          August 24, 2006                                          KDC(8)