xref: /freebsd/crypto/heimdal/kdc/kdc.8 (revision dd41de95a84d979615a2ef11df6850622bf6184e)
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32.\" $Id$
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34.Dd August 24, 2006
35.Dt KDC 8
36.Os HEIMDAL
37.Sh NAME
38.Nm kdc
39.Nd Kerberos 5 server
40.Sh SYNOPSIS
41.Nm
42.Bk -words
43.Oo Fl c Ar file \*(Ba Xo
44.Fl Fl config-file= Ns Ar file
45.Xc
46.Oc
47.Op Fl p | Fl Fl no-require-preauth
48.Op Fl Fl max-request= Ns Ar size
49.Op Fl H | Fl Fl enable-http
50.Op Fl Fl no-524
51.Op Fl Fl kerberos4
52.Op Fl Fl kerberos4-cross-realm
53.Oo Fl r Ar string \*(Ba Xo
54.Fl Fl v4-realm= Ns Ar string
55.Xc
56.Oc
57.Oo Fl P Ar portspec \*(Ba Xo
58.Fl Fl ports= Ns Ar portspec
59.Xc
60.Oc
61.Op Fl Fl detach
62.Op Fl Fl disable-des
63.Op Fl Fl addresses= Ns Ar list of addresses
64.Ek
65.Sh DESCRIPTION
66.Nm
67serves requests for tickets.
68When it starts, it first checks the flags passed, any options that are
69not specified with a command line flag are taken from a config file,
70or from a default compiled-in value.
71.Pp
72Options supported:
73.Bl -tag -width Ds
74.It Fl c Ar file , Fl Fl config-file= Ns Ar file
75Specifies the location of the config file, the default is
76.Pa /var/heimdal/kdc.conf .
77This is the only value that can't be specified in the config file.
78.It Fl p , Fl Fl no-require-preauth
79Turn off the requirement for pre-autentication in the initial AS-REQ
80for all principals.
81The use of pre-authentication makes it more difficult to do offline
82password attacks.
83You might want to turn it off if you have clients
84that don't support pre-authentication.
85Since the version 4 protocol doesn't support any pre-authentication,
86serving version 4 clients is just about the same as not requiring
87pre-athentication.
88The default is to require pre-authentication.
89Adding the require-preauth per principal is a more flexible way of
90handling this.
91.It Fl Fl max-request= Ns Ar size
92Gives an upper limit on the size of the requests that the kdc is
93willing to handle.
94.It Fl H , Fl Fl enable-http
95Makes the kdc listen on port 80 and handle requests encapsulated in HTTP.
96.It Fl Fl no-524
97don't respond to 524 requests
98.It Fl Fl kerberos4
99respond to Kerberos 4 requests
100.It Fl Fl kerberos4-cross-realm
101respond to Kerberos 4 requests from foreign realms.
102This is a known security hole and should not be enabled unless you
103understand the consequences and are willing to live with them.
104.It Fl r Ar string , Fl Fl v4-realm= Ns Ar string
105What realm this server should act as when dealing with version 4
106requests.
107The database can contain any number of realms, but since the version 4
108protocol doesn't contain a realm for the server, it must be explicitly
109specified.
110The default is whatever is returned by
111.Fn krb_get_lrealm .
112This option is only available if the KDC has been compiled with version
1134 support.
114.It Fl P Ar portspec , Fl Fl ports= Ns Ar portspec
115Specifies the set of ports the KDC should listen on.
116It is given as a
117white-space separated list of services or port numbers.
118.It Fl Fl addresses= Ns Ar list of addresses
119The list of addresses to listen for requests on.
120By default, the kdc will listen on all the locally configured
121addresses.
122If only a subset is desired, or the automatic detection fails, this
123option might be used.
124.It Fl Fl detach
125detach from pty and run as a daemon.
126.It Fl Fl disable-des
127disable add des encryption types, makes the kdc not use them.
128.El
129.Pp
130All activities are logged to one or more destinations, see
131.Xr krb5.conf 5 ,
132and
133.Xr krb5_openlog 3 .
134The entity used for logging is
135.Nm kdc .
136.Sh CONFIGURATION FILE
137The configuration file has the same syntax as
138.Xr krb5.conf 5 ,
139but will be read before
140.Pa /etc/krb5.conf ,
141so it may override settings found there.
142Options specific to the KDC only are found in the
143.Dq [kdc]
144section.
145All the command-line options can preferably be added in the
146configuration file.
147The only difference is the pre-authentication flag, which has to be
148specified as:
149.Pp
150.Dl require-preauth = no
151.Pp
152(in fact you can specify the option as
153.Fl Fl require-preauth=no ) .
154.Pp
155And there are some configuration options which do not have
156command-line equivalents:
157.Bl -tag -width "xxx" -offset indent
158.It Li enable-digest = Va boolean
159turn on support for digest processing in the KDC.
160The default is FALSE.
161.It Li check-ticket-addresses = Va boolean
162Check the addresses in the ticket when processing TGS requests.
163The default is TRUE.
164.It Li allow-null-ticket-addresses = Va boolean
165Permit tickets with no addresses.
166This option is only relevant when check-ticket-addresses is TRUE.
167.It Li allow-anonymous = Va boolean
168Permit anonymous tickets with no addresses.
169.It Li max-kdc-datagram-reply-length = Va number
170Maximum packet size the UDP rely that the KDC will transmit, instead
171the KDC sends back a reply telling the client to use TCP instead.
172.It Li transited-policy = Li always-check \*(Ba \
173Li allow-per-principal | Li always-honour-request
174This controls how KDC requests with the
175.Li disable-transited-check
176flag are handled. It can be one of:
177.Bl -tag -width "xxx" -offset indent
178.It Li always-check
179Always check transited encoding, this is the default.
180.It Li allow-per-principal
181Currently this is identical to
182.Li always-check .
183In a future release, it will be possible to mark a principal as able
184to handle unchecked requests.
185.It Li always-honour-request
186Always do what the client asked.
187In a future release, it will be possible to force a check per
188principal.
189.El
190.It encode_as_rep_as_tgs_rep = Va boolean
191Encode AS-Rep as TGS-Rep to be bug-compatible with old DCE code.
192The Heimdal clients allow both.
193.It kdc_warn_pwexpire = Va time
194How long before password/principal expiration the KDC should start
195sending out warning messages.
196.El
197.Pp
198The configuration file is only read when the
199.Nm
200is started.
201If changes made to the configuration file are to take effect, the
202.Nm
203needs to be restarted.
204.Pp
205An example of a config file:
206.Bd -literal -offset indent
207[kdc]
208	require-preauth = no
209	v4-realm = FOO.SE
210.Ed
211.Sh BUGS
212If the machine running the KDC has new addresses added to it, the KDC
213will have to be restarted to listen to them.
214The reason it doesn't just listen to wildcarded (like INADDR_ANY)
215addresses, is that the replies has to come from the same address they
216were sent to, and most OS:es doesn't pass this information to the
217application.
218If your normal mode of operation require that you add and remove
219addresses, the best option is probably to listen to a wildcarded TCP
220socket, and make sure your clients use TCP to connect.
221For instance, this will listen to IPv4 TCP port 88 only:
222.Bd -literal -offset indent
223kdc --addresses=0.0.0.0 --ports="88/tcp"
224.Ed
225.Pp
226There should be a way to specify protocol, port, and address triplets,
227not just addresses and protocol, port tuples.
228.Sh SEE ALSO
229.Xr kinit 1 ,
230.Xr krb5.conf 5
231