Provided by: sssd_1.8.2-0ubuntu1_amd64 bug

NAME

       sssd-krb5 - the configuration file for SSSD

DESCRIPTION

       This manual page describes the configuration of the Kerberos 5 authentication backend for
       sssd(8). For a detailed syntax reference, please refer to the “FILE FORMAT” section of the
       sssd.conf(5) manual page

       The Kerberos 5 authentication backend contains auth and chpass providers. It must be
       paired with identity provider in order to function properly (for example, id_provider =
       ldap). Some information required by the Kerberos 5 authentication backend must be provided
       by the identity provider, such as the user's Kerberos Principal Name (UPN). The
       configuration of the identity provider should have an entry to specify the UPN. Please
       refer to the man page for the applicable identity provider for details on how to configure
       this.

       This backend also provides access control based on the .k5login file in the home directory
       of the user. See .k5login(5) for more details. Please note that an empty .k5login file
       will deny all access to this user. To activate this feature use 'access_provider = krb5'
       in your sssd configuration.

       In the case where the UPN is not available in the identity backend sssd will construct a
       UPN using the format username@krb5_realm.

CONFIGURATION OPTIONS

       If the auth-module krb5 is used in a SSSD domain, the following options must be used. See
       the sssd.conf(5) manual page, section “DOMAIN SECTIONS” for details on the configuration
       of a SSSD domain.

       krb5_server (string)
           Specifies the comma-separated list of IP addresses or hostnames of the Kerberos
           servers to which SSSD should connect in the order of preference. For more information
           on failover and server redundancy, see the “FAILOVER” section. An optional port number
           (preceded by a colon) may be appended to the addresses or hostnames. If empty, service
           discovery is enabled - for more information, refer to the “SERVICE DISCOVERY” section.

           When using service discovery for KDC or kpasswd servers, SSSD first searches for DNS
           entries that specify _udp as the protocol and falls back to _tcp if none are found.

           This option was named “krb5_kdcip” in earlier releases of SSSD. While the legacy name
           is recognized for the time being, users are advised to migrate their config files to
           use “krb5_server” instead.

       krb5_realm (string)
           The name of the Kerberos realm. This option is required and must be specified.

       krb5_kpasswd (string)
           If the change password service is not running on the KDC alternative servers can be
           defined here. An optional port number (preceded by a colon) may be appended to the
           addresses or hostnames.

           For more information on failover and server redundancy, see the “FAILOVER” section.
           Please note that even if there are no more kpasswd servers to try the back end is not
           switch to offline if authentication against the KDC is still possible.

           Default: Use the KDC

       krb5_ccachedir (string)
           Directory to store credential caches. All the substitution sequences of
           krb5_ccname_template can be used here, too, except %d and %P. If the directory does
           not exist it will be created. If %u, %U, %p or %h are used a private directory
           belonging to the user is created. Otherwise a public directory with restricted
           deletion flag (aka sticky bit, see chmod(1) for details) is created.

           Default: /tmp

       krb5_ccname_template (string)
           Location of the user's credential cache. Currently only file based credential caches
           are supported. In the template the following sequences are substituted:

           %u
               login name

           %U
               login UID

           %p
               principal name

           %r
               realm name

           %h
               home directory

           %d
               value of krb5ccache_dir

           %P
               the process ID of the sssd client

           %%
               a literal '%'

           If the template ends with 'XXXXXX' mkstemp(3) is used to create a unique filename in a
           safe way.

           Default: FILE:%d/krb5cc_%U_XXXXXX

       krb5_auth_timeout (integer)
           Timeout in seconds after an online authentication or change password request is
           aborted. If possible the authentication request is continued offline.

           Default: 15

       krb5_validate (boolean)
           Verify with the help of krb5_keytab that the TGT obtained has not been spoofed.

           Default: false

       krb5_keytab (string)
           The location of the keytab to use when validating credentials obtained from KDCs.

           Default: /etc/krb5.keytab

       krb5_store_password_if_offline (boolean)
           Store the password of the user if the provider is offline and use it to request a TGT
           when the provider gets online again.

           Please note that this feature currently only available on a Linux platform. Passwords
           stored in this way are kept in plaintext in the kernel keyring and are potentially
           accessible by the root user (with difficulty).

           Default: false

       krb5_renewable_lifetime (string)
           Request a renewable ticket with a total lifetime given by an integer immediately
           followed by one of the following delimiters:

           s seconds

           m minutes

           h hours

           d days.

           If there is no delimiter s is assumed.

           Please note that it is not possible to mix units. If you want to set the renewable
           lifetime to one and a half hours please use '90m' instead of '1h30m'.

           Default: not set, i.e. the TGT is not renewable

       krb5_lifetime (string)
           Request ticket with a with a lifetime given by an integer immediately followed by one
           of the following delimiters:

           s seconds

           m minutes

           h hours

           d days.

           If there is no delimiter s is assumed.

           Please note that it is not possible to mix units. If you want to set the lifetime to
           one and a half hours please use '90m' instead of '1h30m'.

           Default: not set, i.e. the default ticket lifetime configured on the KDC.

       krb5_renew_interval (integer)
           The time in seconds between two checks if the TGT should be renewed. TGTs are renewed
           if about half of their lifetime is exceeded.

           If this option is not set or 0 the automatic renewal is disabled.

           Default: not set

       krb5_use_fast (string)
           Enables flexible authentication secure tunneling (FAST) for Kerberos
           pre-authentication. The following options are supported:

           never use FAST, this is equivalent to not set this option at all.

           try to use FAST, if the server does not support fast continue without.

           demand to use FAST, fail if the server does not require fast.

           Default: not set, i.e. FAST is not used.

           Please note that a keytab is required to use fast.

           Please note also that sssd supports fast only with MIT Kerberos version 1.8 and above.
           If sssd used with an older version using this option is a configuration error.

       krb5_fast_principal (string)
           Specifies the server principal to use for FAST.

       krb5_canonicalize (boolean)
           Specifies if the host and user principal should be canonicalized. This feature is
           available with MIT Kerberos >= 1.7

           Default: false

FAILOVER

       The failover feature allows back ends to automatically switch to a different server if the
       primary server fails.

   Failover Syntax
       The list of servers is given as a comma-separated list; any number of spaces is allowed
       around the comma. The servers are listed in order of preference. The list can contain any
       number of servers.

   The Failover Mechanism
       The failover mechanism distinguishes between a machine and a service. The back end first
       tries to resolve the hostname of a given machine; if this resolution attempt fails, the
       machine is considered offline. No further attempts are made to connect to this machine for
       any other service. If the resolution attempt succeeds, the back end tries to connect to a
       service on this machine. If the service connection attempt fails, then only this
       particular service is considered offline and the back end automatically switches over to
       the next service. The machine is still considered online and might still be tried for
       another service.

       Further connection attempts are made to machines or services marked as offline after a
       specified period of time; this is currently hard coded to 30 seconds.

       If there are no more machines to try, the back end as a whole switches to offline mode,
       and then attempts to reconnect every 30 seconds.

SERVICE DISCOVERY

       The service discovery feature allows back ends to automatically find the appropriate
       servers to connect to using a special DNS query.

   Configuration
       If no servers are specified, the back end automatically uses service discovery to try to
       find a server. Optionally, the user may choose to use both fixed server addresses and
       service discovery by inserting a special keyword, “_srv_”, in the list of servers. The
       order of preference is maintained. This feature is useful if, for example, the user
       prefers to use service discovery whenever possible, and fall back to a specific server
       when no servers can be discovered using DNS.

   The domain name
       Please refer to the “dns_discovery_domain” parameter in the sssd.conf(5) manual page for
       more details.

   The protocol
       The queries usually specify _tcp as the protocol. Exceptions are documented in respective
       option description.

   See Also
       For more information on the service discovery mechanism, refer to RFC 2782.

EXAMPLE

       The following example assumes that SSSD is correctly configured and FOO is one of the
       domains in the [sssd] section. This example shows only configuration of Kerberos
       authentication, it does not include any identity provider.

               [domain/FOO]
               auth_provider = krb5
               krb5_server = 192.168.1.1
               krb5_realm = EXAMPLE.COM

SEE ALSO

       sssd.conf(5), sssd-ldap(5), sssd(8)

AUTHORS

       The SSSD upstream - http://fedorahosted.org/sssd