**encrypted_timestamp**
This module implements the encrypted timestamp mechanism.
+.. _hostrealm:
+
+hostrealm interface
+###################
+
+The hostrealm section (introduced in release 1.12) controls modules
+for the host-to-realm interface, which affects the local mapping of
+hostnames to realm names and the choice of default realm. The following
+built-in modules exist for this interface:
+
+**profile**
+ This module consults the [domain_realm] section of the profile for
+ authoritative host-to-realm mappings, and the **default_realm**
+ variable for the default realm.
+
+**dns**
+ This module looks for DNS records for fallback host-to-realm
+ mappings and the default realm. It only operates if the
+ **dns_lookup_realm** variable is set to true.
+
+**domain**
+ This module applies heuristics for fallback host-to-realm
+ mappings. It implements the **realm_try_domains** variable, and
+ uses the uppercased parent domain of the hostname if that does not
+ produce a result.
+
.. _localauth:
localauth interface
--- /dev/null
+.. _hostrealm_plugin:
+
+Host-to-realm interface (hostrealm)
+===================================
+
+The host-to-realm interface was first introduced in release 1.12. It
+allows modules to control the local mapping of hostnames to realm
+names as well as the default realm. For a detailed description of the
+hostrealm interface, see the header file
+``<krb5/hostrealm_plugin.h>``.
+
+Although the mapping methods in the hostrealm interface return a list
+of one or more realms, only the first realm in the list is currently
+used by callers. Callers may begin using later responses in the
+future.
+
+Any mapping method may return KRB5_PLUGIN_NO_HANDLE to defer
+processing to a later module.
+
+A module can create and destroy per-library-context state objects
+using the **init** and **fini** methods. If the module does not need
+any state, it does not need to implement these methods.
+
+The optional **host_realm** method allows a module to determine
+authoritative realm mappings for a hostname. The first authoritative
+mapping is used in preference to KDC referrals when getting service
+credentials.
+
+The optional **fallback_realm** method allows a module to determine
+fallback mappings for a hostname. The first fallback mapping is tried
+if there is no authoritative mapping for a realm, and KDC referrals
+failed to produce a succesful result.
+
+The optional **default_realm** method allows a module to determine the
+local default realm.
+
+If a module implements any of the above methods, it must also
+implement **free_list** to ensure that memory is allocated and
+deallocated consistently.