xref: /freebsd/crypto/heimdal/kdc/kdc.8 (revision 3ef51c5fb9163f2aafb1c14729e06a8bf0c4d113)
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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.Op Fl K | Fl Fl kaserver
58.Oo Fl P Ar portspec \*(Ba Xo
59.Fl Fl ports= Ns Ar portspec
60.Xc
61.Oc
62.Op Fl Fl detach
63.Op Fl Fl disable-des
64.Op Fl Fl addresses= Ns Ar list of addresses
65.Ek
66.Sh DESCRIPTION
67.Nm
68serves requests for tickets.
69When it starts, it first checks the flags passed, any options that are
70not specified with a command line flag are taken from a config file,
71or from a default compiled-in value.
72.Pp
73Options supported:
74.Bl -tag -width Ds
75.It Fl c Ar file , Fl Fl config-file= Ns Ar file
76Specifies the location of the config file, the default is
77.Pa /var/heimdal/kdc.conf .
78This is the only value that can't be specified in the config file.
79.It Fl p , Fl Fl no-require-preauth
80Turn off the requirement for pre-autentication in the initial AS-REQ
81for all principals.
82The use of pre-authentication makes it more difficult to do offline
83password attacks.
84You might want to turn it off if you have clients
85that don't support pre-authentication.
86Since the version 4 protocol doesn't support any pre-authentication,
87serving version 4 clients is just about the same as not requiring
88pre-athentication.
89The default is to require pre-authentication.
90Adding the require-preauth per principal is a more flexible way of
91handling this.
92.It Fl Fl max-request= Ns Ar size
93Gives an upper limit on the size of the requests that the kdc is
94willing to handle.
95.It Fl H , Fl Fl enable-http
96Makes the kdc listen on port 80 and handle requests encapsulated in HTTP.
97.It Fl Fl no-524
98don't respond to 524 requests
99.It Fl Fl kerberos4
100respond to Kerberos 4 requests
101.It Fl Fl kerberos4-cross-realm
102respond to Kerberos 4 requests from foreign realms.
103This is a known security hole and should not be enabled unless you
104understand the consequences and are willing to live with them.
105.It Fl r Ar string , Fl Fl v4-realm= Ns Ar string
106What realm this server should act as when dealing with version 4
107requests.
108The database can contain any number of realms, but since the version 4
109protocol doesn't contain a realm for the server, it must be explicitly
110specified.
111The default is whatever is returned by
112.Fn krb_get_lrealm .
113This option is only available if the KDC has been compiled with version
1144 support.
115.It Fl K , Fl Fl kaserver
116Enable kaserver emulation (in case it's compiled in).
117.It Fl P Ar portspec , Fl Fl ports= Ns Ar portspec
118Specifies the set of ports the KDC should listen on.
119It is given as a
120white-space separated list of services or port numbers.
121.It Fl Fl addresses= Ns Ar list of addresses
122The list of addresses to listen for requests on.
123By default, the kdc will listen on all the locally configured
124addresses.
125If only a subset is desired, or the automatic detection fails, this
126option might be used.
127.It Fl Fl detach
128detach from pty and run as a daemon.
129.It Fl Fl disable-des
130disable add des encryption types, makes the kdc not use them.
131.El
132.Pp
133All activities are logged to one or more destinations, see
134.Xr krb5.conf 5 ,
135and
136.Xr krb5_openlog 3 .
137The entity used for logging is
138.Nm kdc .
139.Sh CONFIGURATION FILE
140The configuration file has the same syntax as
141.Xr krb5.conf 5 ,
142but will be read before
143.Pa /etc/krb5.conf ,
144so it may override settings found there.
145Options specific to the KDC only are found in the
146.Dq [kdc]
147section.
148All the command-line options can preferably be added in the
149configuration file.
150The only difference is the pre-authentication flag, which has to be
151specified as:
152.Pp
153.Dl require-preauth = no
154.Pp
155(in fact you can specify the option as
156.Fl Fl require-preauth=no ) .
157.Pp
158And there are some configuration options which do not have
159command-line equivalents:
160.Bl -tag -width "xxx" -offset indent
161.It Li enable-digest = Va boolean
162turn on support for digest processing in the KDC.
163The default is FALSE.
164.It Li check-ticket-addresses = Va boolean
165Check the addresses in the ticket when processing TGS requests.
166The default is TRUE.
167.It Li allow-null-ticket-addresses = Va boolean
168Permit tickets with no addresses.
169This option is only relevant when check-ticket-addresses is TRUE.
170.It Li allow-anonymous = Va boolean
171Permit anonymous tickets with no addresses.
172.It Li max-kdc-datagram-reply-length = Va number
173Maximum packet size the UDP rely that the KDC will transmit, instead
174the KDC sends back a reply telling the client to use TCP instead.
175.It Li transited-policy = Li always-check \*(Ba \
176Li allow-per-principal | Li always-honour-request
177This controls how KDC requests with the
178.Li disable-transited-check
179flag are handled. It can be one of:
180.Bl -tag -width "xxx" -offset indent
181.It Li always-check
182Always check transited encoding, this is the default.
183.It Li allow-per-principal
184Currently this is identical to
185.Li always-check .
186In a future release, it will be possible to mark a principal as able
187to handle unchecked requests.
188.It Li always-honour-request
189Always do what the client asked.
190In a future release, it will be possible to force a check per
191principal.
192.El
193.It encode_as_rep_as_tgs_rep = Va boolean
194Encode AS-Rep as TGS-Rep to be bug-compatible with old DCE code.
195The Heimdal clients allow both.
196.It kdc_warn_pwexpire = Va time
197How long before password/principal expiration the KDC should start
198sending out warning messages.
199.El
200.Pp
201The configuration file is only read when the
202.Nm
203is started.
204If changes made to the configuration file are to take effect, the
205.Nm
206needs to be restarted.
207.Pp
208An example of a config file:
209.Bd -literal -offset indent
210[kdc]
211	require-preauth = no
212	v4-realm = FOO.SE
213.Ed
214.Sh BUGS
215If the machine running the KDC has new addresses added to it, the KDC
216will have to be restarted to listen to them.
217The reason it doesn't just listen to wildcarded (like INADDR_ANY)
218addresses, is that the replies has to come from the same address they
219were sent to, and most OS:es doesn't pass this information to the
220application.
221If your normal mode of operation require that you add and remove
222addresses, the best option is probably to listen to a wildcarded TCP
223socket, and make sure your clients use TCP to connect.
224For instance, this will listen to IPv4 TCP port 88 only:
225.Bd -literal -offset indent
226kdc --addresses=0.0.0.0 --ports="88/tcp"
227.Ed
228.Pp
229There should be a way to specify protocol, port, and address triplets,
230not just addresses and protocol, port tuples.
231.Sh SEE ALSO
232.Xr kinit 1 ,
233.Xr krb5.conf 5
234