@node Setting up a realm, Kerberos 4 issues, Building and Installing, Top @chapter Setting up a realm A @cindex realm realm is an administrative domain. The name of a Kerberos realm is usually the Internet domain name in uppercase. Call your realm the same as your Internet domain name if you do not have strong reasons for not doing so. It will make life easier for you and everyone else. @section Configuration file To setup a realm you will first have to create a configuration file: @file{/etc/krb5.conf}. The @file{krb5.conf} file can contain many configuration options, some of which are described here. There is a sample @file{krb5.conf} supplied with the distribution. The configuration file is a hierarchical structure consisting of sections, each containing a list of bindings (either variable assignments or subsections). A section starts with @samp{[section-name]}. A binding consists of a left hand side, an equal (@samp{=}) and a right hand side. The left hand side tag must be separated from the equal with some whitespace. Subsections has a @samp{@{} as the first non-whitespace character after the equal. All other bindings are treated as variable assignments. The value of a variable extends to the end of the line. @example [section1] a-subsection = @{ var = value1 other-var = value with @{@} sub-sub-section = @{ var = 123 @} @} var = some other value [section2] var = yet another value @end example To denote entries in the config file, the names of sections and bindings will be given separated with slashes (@samp{/}). The @samp{other-var} variable will thus be @samp{section1/a-subsection/other-var}. For in-depth information about the contents of the config file, refer to the @file{krb5.conf} manual page. Some of the more important sections are briefly described here. The @samp{libdefaults} section contains a list of library configuration parameters, such as the default realm and the timeout for kdc responses. The @samp{realms} section contains information about specific realms, such as where they hide their KDC. This section serves the same purpose as the Kerberos 4 @file{krb.conf} file, but can contain more information. Finally the @samp{domain_realm} section contains a list of mappings from domains to realms, equivalent to the Kerberos 4 @file{krb.realms} file. To continue with the realm setup, you will have to create a config file, with contents similar to the following. @example [libdefaults] default_realm = MY.REALM [realms] MY.REALM = @{ kdc = my.kdc @} [domain_realm] .my.domain = MY.REALM @end example If you use a realm name equal to your domain name, you can omit the @samp{libdefaults}, and @samp{domain_realm}, sections. @section Creating the database The database library will look for the database in @file{/var/heimdal}, so you should probably create that directory. The keys of all the principals are stored in the database. If you choose to, these can be encrypted with a master key. You do not have to remember this key (or password), but just to enter it once and it will be stored in a file (@file{/var/heimdal/m-key}). If you want to have a master key, run @samp{kstash} to create this master key: @example # kstash Master key: Verifying password - Master key: @end example To initialise the database use the @code{kdb_edit} program. First issue a @kbd{init MY.REALM} command. This will create the database and insert default principals for that realm. You can have more than one realm in one database, so @samp{init} does not destroy any old database. Before creating the database, @samp{init} will ask you some questions about default and max ticket lifetimes. The default values should be fine. After creating the database you should probably add yourself. You do this with the @samp{ank} command. It takes as argument the name of a principal. The principal should contain a realm, so if you haven't setup a default realm, you will need to explicitly include the realm. @example # kdb_edit kdb_edit: Database is encrypted kdb_edit> init MY.REALM Realm max ticket life: [infinite] Realm max renewable ticket life: [infinite] Default ticket life: [1 day] Default renewable ticket life: [7 days] kdb_edit> ank me Max ticket life [1 day]: Max renewable ticket [7 days]: Flags [client, server, postdate, renewable, proxiable, forwardable]: Password: Verifying password - Password: @end example Now start the KDC and try getting a ticket. @example # kdc & # kinit me me@@MY.REALMS's Password: # klist Credentials cache: /tmp/krb5cc_3008 Principal: me@@MY.REALM Issued Expires Principal Aug 25 07:25:55 Aug 25 17:25:55 krbtgt/MY.REALM@@MY.REALM @end example To verify that the contents of the database you can use the @samp{dump} command to list all the entries. It should look something similar to the following example (note that the entries here are divided into two lines for typographical reasons): @smallexample kdb_edit> dump krbtgt/MY.REALM@@MY.REALM 1:0:1:0001010000010000:- \ 19970908002104:kadmin@@MY.REALM - - - - - - 62 default@@MY.REALM 0 \ 19970908002104:kadmin@@MY.REALM - - - - 86400 604800 128 kadmin/changepw@@MY.REALM 1:0:1:2213b905229d3990:- \ 19970908002104:kadmin@@MY.REALM - - - - 86400 604800 545 me@@MY.REALM 1:0:1:908f1cf6110487cc:- \ 19970908002112:kadmin@@MY.REALM - - - - 86400 604800 126 @end smallexample @section keytabs To extract a service ticket from the database and put it in a keytab you need to first create the principal in the database with @samp{ank} (entering @kbd{random} for password) and then extract it with @samp{ext_keytab}. @example # kdb_edit kdb_edit> ank host/my.host.name Max ticket life [1 day]: Max renewable life [1 week]: Flags [client, server, postdate, renewable, proxiable, forwardable]: Password: Verifying password - Password: kdb_edit> ext host/my.host.name # ktutil list Version Type Principal 1 1 host/my.host.name@@MY.REALM @end example @section Testing clients and servers Now you should be able to run all the clients and servers. Refer to the appropriate man pages for information on how to use them.