MIT Kerberos Documentation



kinit [-V] [-l lifetime] [-s start_time] [-r renewable_life] [-p | -P] [-f | -F] [-a] [-A] [-C] [-E] [-v] [-R] [-k [-t keytab_file]] [-c cache_name] [-n] [-S service_name] [-T armor_ccache] [-X attribute[=value]] [principal]


kinit obtains and caches an initial ticket-granting ticket for principal.


display verbose output.
-l lifetime

requests a ticket with the lifetime lifetime. The integer value for lifetime must be followed immediately by one of the following delimiters:

s  seconds
m  minutes
h  hours
d  days

as in kinit -l 90m. You cannot mix units; a value of 3h30m will result in an error.

If the -l option is not specified, the default ticket lifetime (configured by each site) is used. Specifying a ticket lifetime longer than the maximum ticket lifetime (configured by each site) results in a ticket with the maximum lifetime.

-s start_time
requests a postdated ticket, valid starting at start_time. Postdated tickets are issued with the invalid flag set, and need to be resubmitted to the KDC for validation before use.
-r renewable_life
requests renewable tickets, with a total lifetime of renewable_life. The duration is in the same format as the -l option, with the same delimiters.
requests forwardable tickets.
requests non-forwardable tickets.
requests proxiable tickets.
requests non-proxiable tickets.
requests tickets restricted to the host’s local address[es].
requests tickets not restricted by address.
requests canonicalization of the principal name, and allows the KDC to reply with a different client principal from the one requested.
treats the principal name as an enterprise name (implies the -C option).
requests that the ticket-granting ticket in the cache (with the invalid flag set) be passed to the KDC for validation. If the ticket is within its requested time range, the cache is replaced with the validated ticket.
requests renewal of the ticket-granting ticket. Note that an expired ticket cannot be renewed, even if the ticket is still within its renewable life.
-k [-t keytab_file]
requests a ticket, obtained from a key in the local host’s keytab. The location of the keytab may be specified with the -t keytab_file option; otherwise the default keytab will be used. By default, a host ticket for the local host is requested, but any principal may be specified. On a KDC, the special keytab location KDB: can be used to indicate that kinit should open the KDC database and look up the key directly. This permits an administrator to obtain tickets as any principal that supports authentication based on the key.

Requests anonymous processing. Two types of anonymous principals are supported.

For fully anonymous Kerberos, configure pkinit on the KDC and configure pkinit_anchors in the client’s krb5.conf. Then use the -n option with a principal of the form @REALM (an empty principal name followed by the at-sign and a realm name). If permitted by the KDC, an anonymous ticket will be returned.

A second form of anonymous tickets is supported; these realm-exposed tickets hide the identity of the client but not the client’s realm. For this mode, use kinit -n with a normal principal name. If supported by the KDC, the principal (but not realm) will be replaced by the anonymous principal.

As of release 1.8, the MIT Kerberos KDC only supports fully anonymous operation.

-T armor_ccache
Specifies the name of a credentials cache that already contains a ticket. If supported by the KDC, this cache will be used to armor the request, preventing offline dictionary attacks and allowing the use of additional preauthentication mechanisms. Armoring also makes sure that the response from the KDC is not modified in transit.
-c cache_name

use cache_name as the Kerberos 5 credentials (ticket) cache location. If this option is not used, the default cache location is used.

The default cache location may vary between systems. If the KRB5CCNAME environment variable is set, its value is used to locate the default cache. If a principal name is specified and the type of the default cache supports a collection (such as the DIR type), an existing cache containing credentials for the principal is selected or a new one is created and becomes the new primary cache. Otherwise, any existing contents of the default cache are destroyed by kinit.

-S service_name
specify an alternate service name to use when getting initial tickets.
-X attribute[=value]

specify a pre-authentication attribute and value to be interpreted by pre-authentication modules. The acceptable attribute and value values vary from module to module. This option may be specified multiple times to specify multiple attributes. If no value is specified, it is assumed to be “yes”.

The following attributes are recognized by the PKINIT pre-authentication mechanism:

specify where to find user’s X509 identity information
specify where to find trusted X509 anchor information
specify use of RSA, rather than the default Diffie-Hellman protocol


kinit uses the following environment variables:

Location of the default Kerberos 5 credentials cache, in the form type:residual. If no type prefix is present, the FILE type is assumed. The type of the default cache may determine the availability of a cache collection; for instance, a default cache of type DIR causes caches within the directory to be present in the collection.


default location of Kerberos 5 credentials cache ([uid] is the decimal UID of the user).
default location for the local host’s keytab.


klist, kdestroy, kerberos(1)