1KDC(8) BSD System Manager's Manual KDC(8)
2
4 kdc — Kerberos 5 server
5
7 kdc [-c file | --config-file=file] [-p | --no-require-preauth]
8 [--max-request=size] [-H | --enable-http] [-r string |
9 --v4-realm=string] [-P portspec | --ports=portspec] [--detach]
10 [--disable-des] [--addresses=list of addresses]
11
13 kdc serves requests for tickets. When it starts, it first checks the
14 flags passed, any options that are not specified with a command line flag
15 are taken from a config file, or from a default compiled-in value.
16 Options supported:
18 -c file, --config-file=file
20 Specifies the location of the config file, the default is
21 /var/heimdal/kdc.conf. This is the only value that can't be
22 specified in the config file.
23 -p, --no-require-preauth
25 Turn off the requirement for pre-autentication in the initial AS-
26 REQ for all principals. The use of pre-authentication makes it
27 more difficult to do offline password attacks. You might want to
28 turn it off if you have clients that don't support pre-authenti‐
29 cation. Since the version 4 protocol doesn't support any pre-au‐
30 thentication, serving version 4 clients is just about the same as
31 not requiring pre-athentication. The default is to require pre-
32 authentication. Adding the require-preauth per principal is a
33 more flexible way of handling this.
34 --max-request=size
36 Gives an upper limit on the size of the requests that the kdc is
37 willing to handle.
38 -H, --enable-http
40 Makes the kdc listen on port 80 and handle requests encapsulated
41 in HTTP.
42 -r string, --v4-realm=string
44 What realm this server should act as when dealing with version 4
45 requests. The database can contain any number of realms, but
46 since the version 4 protocol doesn't contain a realm for the
47 server, it must be explicitly specified. The default is whatever
48 is returned by krb_get_lrealm(). This option is only available
49 if the KDC has been compiled with version 4 support.
50 -P portspec, --ports=portspec
52 Specifies the set of ports the KDC should listen on. It is given
53 as a white-space separated list of services or port numbers.
54 --addresses=list of addresses
56 The list of addresses to listen for requests on. By default, the
57 kdc will listen on all the locally configured addresses. If only
58 a subset is desired, or the automatic detection fails, this op‐
59 tion might be used.
60 --detach
62 detach from pty and run as a daemon.
63 --disable-des
65 disable all des encryption types, makes the kdc not use them.
66 All activities are logged to one or more destinations, see krb5.conf(5),
68 and krb5_openlog(3). The entity used for logging is kdc.
69
71 The configuration file has the same syntax as krb5.conf(5), but will be
72 read before /etc/krb5.conf, so it may override settings found there. Op‐
73 tions specific to the KDC only are found in the “[kdc]” section. All the
74 command-line options can preferably be added in the configuration file.
75 The only difference is the pre-authentication flag, which has to be spec‐
76 ified as:
77 require-preauth = no
79 (in fact you can specify the option as --require-preauth=no).
81 And there are some configuration options which do not have command-line
83 equivalents:
84 enable-digest = boolean
86 turn on support for digest processing in the KDC. The default
87 is FALSE.
88 check-ticket-addresses = boolean
90 Check the addresses in the ticket when processing TGS re‐
91 quests. The default is TRUE.
92 allow-null-ticket-addresses = boolean
94 Permit tickets with no addresses. This option is only rele‐
95 vant when check-ticket-addresses is TRUE.
96 allow-anonymous = boolean
98 Permit anonymous tickets with no addresses.
99 historical_anon_realm = boolean
101 Enables pre-7.0 non-RFC-comformant KDC behavior. With this
102 option set to true the client realm in anonymous pkinit AS
103 replies will be the requested realm, rather than the RFC-con‐
104 formant WELLKNOWN:ANONYMOUS realm. This can have a security
105 impact on servers that expect to grant access to anonymous-
106 but-authenticated to the KDC users of the realm in question:
107 they would also grant access to unauthenticated anonymous
108 users. As such, it is not recommend to set this option to
109 true.
110 max-kdc-datagram-reply-length = number
112 Maximum packet size the UDP rely that the KDC will transmit,
113 instead the KDC sends back a reply telling the client to use
114 TCP instead.
115 transited-policy = always-check | allow-per-principal |
117 always-honour-request
118 This controls how KDC requests with the
119 disable-transited-check flag are handled. It can be one of:
120 always-check
122 Always check transited encoding, this is the de‐
123 fault.
124 allow-per-principal
126 Currently this is identical to always-check. In a
127 future release, it will be possible to mark a prin‐
128 cipal as able to handle unchecked requests.
129 always-honour-request
131 Always do what the client asked. In a future re‐
132 lease, it will be possible to force a check per
133 principal.
134 encode_as_rep_as_tgs_rep = boolean
136 Encode AS-Rep as TGS-Rep to be bug-compatible with old DCE
137 code. The Heimdal clients allow both.
138 kdc_warn_pwexpire = time
140 How long before password/principal expiration the KDC should
141 start sending out warning messages.
142 The configuration file is only read when the kdc is started. If changes
144 made to the configuration file are to take effect, the kdc needs to be
145 restarted.
146 An example of a config file:
148 [kdc]
150 require-preauth = no
151 v4-realm = FOO.SE
152
154 If the machine running the KDC has new addresses added to it, the KDC
155 will have to be restarted to listen to them. The reason it doesn't just
156 listen to wildcarded (like INADDR_ANY) addresses, is that the replies has
157 to come from the same address they were sent to, and most OS:es doesn't
158 pass this information to the application. If your normal mode of opera‐
159 tion require that you add and remove addresses, the best option is proba‐
160 bly to listen to a wildcarded TCP socket, and make sure your clients use
161 TCP to connect. For instance, this will listen to IPv4 TCP port 88 only:
162 kdc --addresses=0.0.0.0 --ports="88/tcp"
164 There should be a way to specify protocol, port, and address triplets,
166 not just addresses and protocol, port tuples.
167
169 kinit(1), krb5.conf(5)
170HEIMDAL August 24, 2006 HEIMDAL