This is Info file kerberos-admin.info, produced by Makeinfo-1.55 from the input file admin.texinfo.  File: kerberos-admin.info, Node: Top, Next: Introduction, Prev: (dir), Up: (dir) This document describes how to administrate a Kerberos V5 installation. Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1996 by the Massachusetts Institute of Technology. Export of software employing encryption from the United States of America may require a specific license from the United States Government. It is the responsibility of any person or organization contemplating export to obtain such a license before exporting. WITHIN THAT CONSTRAINT, permission to use, copy, modify, and distribute this software and its documentation for any purpose and without fee is hereby granted, provided that the above copyright notice appear in all copies and that both that copyright notice and this permission notice appear in supporting documentation, and that the name of M.I.T. not be used in advertising or publicity pertaining to distribution of the software without specific, written prior permission. M.I.T. makes no representations about the suitability of this software for any purpose. It is provided "as is" without express or implied warranty. Kerberos V5 includes documentation and software developed at the University of California at Berkeley, which includes this copyright notice: Copyright (C) 1983 Regents of the University of California. All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. 3. All advertising materials mentioning features or use of this software must display the following acknowledgement: This product includes software developed by the University of California, Berkeley and its contributors. 4. Neither the name of the University nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. Permission is granted to make and distribute verbatim copies of this manual provided the copyright notices and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided also that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Permission is granted to copy and distribute translations of this manual into another language, under the above conditions for modified versions. * Menu: * Introduction:: * How Kerberos Works:: * Administrating Kerberos Database Entries:: * Application Servers:: * Backups of Secure Hosts:: * Bug Reporting:: * Appendix::  File: kerberos-admin.info, Node: Introduction, Next: How Kerberos Works, Prev: Top, Up: Top Introduction ************ * Menu: * Why Should I use Kerberos?:: * Kerberos V5 Documentation:: * Overview of This Guide::  File: kerberos-admin.info, Node: Why Should I use Kerberos?, Next: @value{PRODUCT} Documentation, Prev: Introduction, Up: Introduction Why Should I use Kerberos? ========================== Since Kerberos negotiates authenticated, and optionally encrypted, communications between two points anywhere on the internet, it provides a layer of security that is not dependent on which side of a firewall either client is on. Since studies have shown that half of the computer security breaches in industry happen from inside firewalls, Kerberos V5 from MIT will play a vital role in the security of your network.  File: kerberos-admin.info, Node: @value{PRODUCT} Documentation, Next: Overview of This Guide, Prev: Why Should I use Kerberos?, Up: Introduction Kerberos V5 ocumentation ========================= This document is one piece of the document set for Kerberos V5. The documents, and their intended audiences, are: This document is one piece of the document set for Kerberos V5. The documents, and their intended audiences, are: * Kerberos V5 Installation Guide: a concise guide for installing Kerberos V5. Kerberos administrators (particularly whoever will be making site-wide decisions about the installation) and the system administrators who will be installing the software should read this guide. * Kerberos V5 System Administrator's Guide: a sysadmin's guide to administering a Kerberos installation. The System Administrator's Guide describes the administration software and suggests policies and procedures for administering a Kerberos installation. Anyone who will have administrative access to your Kerberos database should read this guide. * Kerberos V5 UNIX User's Guide: a guide to using the Kerberos UNIX client programs. All users on UNIX systems should read this guide, particularly the "Tutorial" section.  File: kerberos-admin.info, Node: Overview of This Guide, Prev: @value{PRODUCT} Documentation, Up: Introduction Overview of This Guide ====================== The next chapter describes how Kerberos works. Chapter three describes administration of the principals in the Kerberos database. Chapter four describes administrative programs for manipulating the Kerberos database as a whole. Chapter five describes issues to consider when adding an application server to the database. Chapter six describes our problem reporting system. The appendices include sample configuration files, the list of Kerberos error messages, and a complete list of the time zones understood by `kadmin'.  File: kerberos-admin.info, Node: How Kerberos Works, Next: Administrating Kerberos Database Entries, Prev: Introduction, Up: Top How Kerberos Works ****************** This section provides a simplified description of a general user's interaction with the Kerberos system. This interaction happens transparently--users don't need to know and probably don't care about what's going on--but Kerberos administrators might find a schematic description of the process useful. This description glosses over a lot of details; for more information, see Kerberos: An Authentication Service for Open Network Systems, a paper presented at Winter USENIX 1988, in Dallas, Texas. This paper can be retreived by FTP from `athena-dist.mit.edu', in the location: `/pub/ATHENA/kerberos/doc/USENIX.ps'. * Menu: * Network Services and Their Client Programs:: * Kerberos Tickets:: * The Kerberos Database:: * Kerberos Realms:: * The Ticket-Granting Ticket:: * Network Services and the Master Database:: * The User-Kerberos Interaction:: * Definitions::  File: kerberos-admin.info, Node: Network Services and Their Client Programs, Next: Kerberos Tickets, Prev: How Kerberos Works, Up: How Kerberos Works Network Services and Their Client Programs ========================================== In an environment that provides network services, you use "client" programs to request "services" from "server" programs that are somewhere on the network. Suppose you have logged in to a workstation and you want to `rlogin' to a typical UNIX host. You use the local `rlogin' client program to contact the remote machine's `rlogind' daemon.  File: kerberos-admin.info, Node: Kerberos Tickets, Next: The Kerberos Database, Prev: Network Services and Their Client Programs, Up: How Kerberos Works Kerberos Tickets ================ Under Kerberos, the `klogind' daemon allows you to login to a remote machine if you can provide `klogind' a Kerberos ticket which proves your identity. In addition to the ticket, you must also have possession of the corresponding ticket session key. The combination of a ticket and the ticket's session key is known as a credential. Typically, a client program automatically obtains credentials identifying the person using the client program. The credentials are obtained from a Kerberos server that resides somewhere on the network. A Kerberos server maintains a database of user, server, and password information.  File: kerberos-admin.info, Node: The Kerberos Database, Next: Kerberos Realms, Prev: Kerberos Tickets, Up: How Kerberos Works The Kerberos Database ===================== Kerberos will give you credentials only if you have an entry in the Kerberos server's "Kerberos database". Your database entry includes your Kerberos "principal" (an identifying string, which is often just your username), and your Kerberos password. Every Kerberos user must have an entry in this database.  File: kerberos-admin.info, Node: Kerberos Realms, Next: The Ticket-Granting Ticket, Prev: The Kerberos Database, Up: How Kerberos Works Kerberos Realms =============== Each administrative domain will have its own Kerberos database, which contains information about the users and services for that particular site or administrative domain. This administrative domain is the "Kerberos realm". Each Kerberos realm will have at least one Kerberos server, where the master Kerberos database for that site or administrative domain is stored. A Kerberos realm may also have one or more "slave servers", which have read-only copies of the Kerberos database that are periodically propagated from the master server. For more details on how this is done, see the "Set Up the Slave KDCs for Database Propagation" and "Propagate the Database to Each Slave KDC" sections of the Kerberos V5 Installation Guide.  File: kerberos-admin.info, Node: The Ticket-Granting Ticket, Next: Network Services and the Master Database, Prev: Kerberos Realms, Up: How Kerberos Works The Ticket-Granting Ticket ========================== The `kinit' command prompts for your password. If you enter it successfully, you will obtain a "ticket-granting ticket" and a "ticket session key" which gives you the right to use the ticket. This combination of the ticket and its associated key is known as your "credentials". As illustrated below, client programs use your ticket-granting ticket credentials in order to obtain client-specific credentials as needed. Your credentials are stored in a "credentials cache", which is often just a file in `/tmp'. The credentials cache is also called the "ticket file", especially in Kerberos V4 documentation. Note, however, that a credentials cache does not have to be stored in a file.  File: kerberos-admin.info, Node: Network Services and the Master Database, Next: The User--Kerberos Interaction, Prev: The Ticket-Granting Ticket, Up: How Kerberos Works Network Services and the Master Database ======================================== The master database also contains entries for all network services that require Kerberos authentication. Suppose that your site has a machine, `laughter.mit.edu', that requires Kerberos authentication from anyone who wants to `rlogin' to it. The host's Kerberos realm is `ATHENA.MIT.EDU'. This service must be registered in the Kerberos database, using the proper service name, which in this case is the "principal": host/laughter.mit.edu@ATHENA.MIT.EDU The `/' character separates the Kerberos "primary" (in this case, `host') from the "instance" (in this case, `laughter.mit.edu'); the `@' character separates the realm name (in this case, `ATHENA.MIT.EDU') from the rest of the principal. The primary, `host', denotes the name or type of the service that is being offered: generic host-level access to the machine. The instance, `laughter.mit.edu', names the specific machine that is offering this service. There will generally be many different machines, each offering one particular type of service, and the instance serves to give each one of these servers a different Kerberos principal. * Menu: * The Keytab File::  File: kerberos-admin.info, Node: The Keytab File, Prev: Network Services and the Master Database, Up: Network Services and the Master Database The Keytab File --------------- For each service, there must also be a "service key" known only by Kerberos and the service. On the Kerberos server, the service key is stored in the Kerberos database. On the server host, these service keys are stored in "key tables", which are files known as "keytabs".(1) For example, the service keys used by services that run as root are usually stored in the keytab file `/etc/v5srvtab'. N.B.: This service key is the equivalent of the service's password, and must be kept secure. Data which is meant to be read only by the service is encrypted using this key. ---------- Footnotes ---------- (1) Keytabs were called "srvtabs" in Kerberos V4.  File: kerberos-admin.info, Node: The User--Kerberos Interaction, Next: Definitions, Prev: Network Services and the Master Database, Up: How Kerberos Works The User-Kerberos Interaction ============================= Suppose that you walk up to a host intending to login to it, and then `rlogin' to the machine `laughter'. Here's what happens: 1. You login to the workstation and use the `kinit' command to get a ticket-granting ticket. This command prompts you for your Kerberos password. (On systems running the Kerberos V5 `login' program, this may be done as part of the login process, not requiring the user to run a separate program.) A. The `kinit' command sends your request to the Kerberos master server machine. The server software looks for your principal name's entry in the Kerberos database. B. If this entry exists, the Kerberos server creates and returns a ticket-granting ticket and the key which allows you to use it, encrypted by your password. If `kinit' can decrypt the Kerberos reply using the password you provide, it stores this ticket in a credentials cache on your local machine for later use. The name of the credentials cache can be specified in the `KRB5_CCNAME' environment variable. If this variable is not set, the name of the file will be `/tmp/krb5cc_', where is your UNIX user-id, represented in decimal format. 2. Now you use the `rlogin' client to access the machine `laughter'. host% rlogin laughter A. The `rlogin' client checks your ticket file to see if you have a ticket for the `host' service for `laughter'. You don't, so `rlogin' uses the credential cache's ticket-granting ticket to make a request to the master server's ticket-granting service. B. This ticket-granting service receives the request for a ticket for `host/laughter.mit.edu', and looks in the master database for an entry for `host/laughter.mit.edu'. If the entry exists, the ticket-granting service issues you a ticket for that service. That ticket is also cached in your credentials cache. C. The `rlogin' client now sends that ticket to the `laughter' `klogind' service program. The service program checks the ticket by using its own service key. If the ticket is valid, it now knows your identity. If you are allowed to login to `laughter' (because your username matches one in /etc/passwd, or your Kerberos principal is in the appropriate `.k5login' file), `klogind' will let you login.  File: kerberos-admin.info, Node: Definitions, Prev: The User--Kerberos Interaction, Up: How Kerberos Works Definitions =========== Following are definitions of some of the Kerberos terminology. client an entity that can obtain a ticket. This entity is usually either a user or a host. host a computer that can be accessed over a network. Kerberos in Greek mythology, the three-headed dog that guards the entrance to the underworld. In the computing world, Kerberos is a network security package that was developed at MIT. KDC Key Distribution Center. A machine that issues Kerberos tickets. keytab a key table file containing one or more keys. A host or service uses a "keytab" file in much the same way as a user uses his/her password. principal a string that names a specific entity to which a set of credentials may be assigned. It generally has three parts: primary the first part of a Kerberos principal. In the case of a user, it is the username. In the case of a service, it is the name of the service. instance the second part of a Kerberos principal. It gives information that qualifies the primary. The instance may be null. In the case of a user, the instance is often used to describe the intended use of the corresponding credentials. In the case of a host, the instance is the fully qualified hostname. realm the logical network served by a single Kerberos database and a set of Key Distribution Centers. By convention, realm names are generally all uppercase letters, to differentiate the realm from the internet domain. The typical format of a typical Kerberos principal is primary/instance@REALM. service any program or computer you access over a network. Examples of services include "host" (a host, e.g., when you use `telnet' and `rsh'), "ftp" (FTP), "krbtgt" (authentication; cf. ticket-granting ticket), and "pop" (email). ticket a temporary set of electronic credentials that verify the identity of a client for a particular service. TGT Ticket-Granting Ticket. A special Kerberos ticket that permits the client to obtain additional Kerberos tickets within the same Kerberos realm.  File: kerberos-admin.info, Node: Administrating Kerberos Database Entries, Next: Application Servers, Prev: How Kerberos Works, Up: Top Administrating the Kerberos Database ************************************ Your Kerberos database contains all of your realm's Kerberos principals, their passwords, and other administrative information about each principal. For the most part, you will use the `kdb5_util' program to manipulate the Kerberos database as a whole, and the `kadmin' program to make changes to the entries in the database. (One notable exception is that users will use the `kpasswd' program to change their own passwords.) The `kadmin' program has its own command-line interface, to which you type the database administrating commands. `Kdb5_util' provides a means to create, delete, load, or dump a Kerberos database. It also includes a command to stash a copy of the master database key in a file on a KDC, so that the KDC can authenticate itself to the `kadmind' and `krb5kdc' daemons at boot time. `Kadmin' provides for the maintenance of Kerberos principals, KADM5 policies, and service key tables (keytabs). It exists as both a Kerberos client, `kadmin', using Kerberos authentication and an RPC, to operate securely from anywhere on the network, and as a local client, `kadmin.local', intended to run directly on the KDC without Kerberos authentication. Other than the fact that the remote client uses Kerberos to authenticate the person using it, the functionalities of the two versions are identical. The local version is necessary to enable you to set up enough of the database to be able to use the remote version. It replaces the now obsolete `kdb5_edit' (except for database dump and load, which are provided by `kdb5_util'). The remote version authenticates to the KADM5 server using the service principal `kadmin/admin'. If the credentials cache contains a ticket for the `kadmin/admin' principal, and the `-c credentials_cache' option is specified, that ticket is used to authenticate to KADM5. Otherwise, the `-p' and `-k' options are used to specify the client Kerberos principal name used to authenticate. Once kadmin has determined the principal name, it requests a `kadmin/admin' Kerberos service ticket from the KDC, and uses that service ticket to authenticate to KADM5. * Menu: * Kadmin Options:: * Date Format:: * Principals:: * Policies:: * Dumping a Kerberos Database to a File:: * Restoring a Kerberos Database from a Dump File:: * Creating a Stash File:: * Creating and Destroying a Kerberos Database::  File: kerberos-admin.info, Node: Kadmin Options, Next: Date Format, Prev: Administrating Kerberos Database Entries, Up: Administrating Kerberos Database Entries Kadmin Options ============== You can invoke `kadmin' with any of the following options: -r REALM Use REALM as the default Kerberos realm for the database. -p principal Use the Kerberos principal principal to authenticate to Kerberos. If this option is not given, `kadmin' will append `admin' to either the primary principal name, the environment variable USER, or to the username obtained grom `getpwuid', in order of preference. -k keytab Use the keytab keytab to decrypt the KDC response instead of prompting for a password on the TTY. In this case, the principal will be `host/hostname'. -c credentials cache Use credentials_cache as the credentials cache. The credentials cache should contain a service ticket for the `kadmin/admin' service, which can be acquired with the `kinit' program. If this option is not specified, `kadmin' requests a new service ticket from the KDC, and stores it in its own temporary ccache. -w password Use password as the password instead of prompting for one on the TTY. Note: placing the password for a Kerberos principal with administration access into a shell script can be dangerous if unauthorized users gain read access to the script. -q query Pass query directly to `kadmin'. This is useful for writing scripts that pass specific queries to `kadmin'.  File: kerberos-admin.info, Node: Date Format, Next: Principals, Prev: Kadmin Options, Up: Administrating Kerberos Database Entries Date Format =========== Many of the `kadmin' commands take a duration or time as an argument. The date can appear in a wide variety of formats, such as: "15 minutes" "7 days" "1 month" "2 hours" "400000 seconds" "next year" "this Monday" "next Monday" yesterday tomorrow now "second Monday" fortnight "3/31/92 10:00:07 PST" "January 23, 1987 10:05pm" "22:00 GMT" Note that if the date specification contains spaces, you must enclose it in double quotes. Note also that you cannot use a number without a unit. (I.e., ""60 seconds"" is correct, but "60" is incorrect.) All keywords are case-insensitive. The following is a list of all of the allowable keywords. Months january, jan, february, feb, march, mar, april, apr, may, june, jun, july, jul, august, aug, september, sept, sep, october, oct, november, nov, december, dec Days sunday, sun, monday, mon, tuesday, tues, tue, wednesday, wednes, wed, thursday, thurs, thur, thu, friday, fri, saturday, sat Units year, month, fortnight, week, day, hour, minute, min, second, sec Relative tomorrow, yesterday, today, now, last, this, next, first, third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh, twelfth, ago Time Zones `kadmin' recognizes abbreviations for most of the world's time zones. A complete listing appears in *Note kadmin Time Zones::. 12-hour Time Delimiters am, pm  File: kerberos-admin.info, Node: Principals, Next: Policies, Prev: Date Format, Up: Administrating Kerberos Database Entries Principals ========== Each entry in the Kerberos database contains a Kerberos principal (*note Definitions::.) and the attributes and policies associated with that principal. * Menu: * Retrieving Information About a Principal:: * Privileges:: * Adding or Modifying Principals:: * Deleting Principals:: * Changing Passwords:: * Renaming Principals::  File: kerberos-admin.info, Node: Retrieving Information About a Principal, Next: Privileges, Prev: Principals, Up: Principals Retrieving Information About a Principal ---------------------------------------- * Menu: * Attributes:: * Retrieving a List of Principals::  File: kerberos-admin.info, Node: Attributes, Next: Retrieving a List of Principals, Prev: Retrieving Information About a Principal, Up: Retrieving Information About a Principal Attributes .......... To retrieve a listing of the attributes and/or policies associated with a principal, use the `kadmin' `get_principal' command, which requires the "inquire" administrative privilege. The syntax is: get_principal principal The `get_principal' command has the alias `getprinc'. For example, suppose you wanted to view the attributes of the principals `jennifer/root@ATHENA.MIT.EDU' and `systest@ATHENA.MIT.EDU'. You would type: shell% kadmin kadmin: getprinc jennifer/root Principal: jennifer/root@ATHENA.MIT.EDU Key version: 3 Maximum life: 1 day 00:00:00 Maximum renewable life: 7 days 00:00:00 Master key version: 1 Expires: Mon Jan 18 22:14:07 EDT 2038 Password expires: Mon Sep 19 14:40:00 EDT 1996 Password last changed: Mon Jan 31 02:06:40 EDT 1996 Last modified: by joeadmin/admin@ATHENA.MIT.EDU on Wed Jul 13 18:27:08 EDT 1996 Attributes: DISALLOW_FORWARDABLE, DISALLOW_PROXIABLE, REQUIRES_HW_AUTH Salt type: DEFAULT kadmin: The `get_principal' command has a `-terse' option, which lists the fields as a quoted, tab-separated string. For example: kadmin: getprinc -terse systest systest@ATHENA.MIT.EDU 3 86400 604800 1 785926535 753241234 785900000 joeadmin/admin@ATHENA.MIT.EDU 786100034 0 0 kadmin:  File: kerberos-admin.info, Node: Retrieving a List of Principals, Prev: Attributes, Up: Retrieving Information About a Principal Retrieving a List of Principals ............................... To generate a listing of principals, use the `kadmin' `list_principals' command, which requires the "list" privilege. The syntax is: list_principals [expression] where expression is a shell-style glob expression that can contain the characters `*', `?', `[', and `]'. All policy names matching the expression are displayed. The `list_principals' command has the alias `listprincs'. For example: kadmin: listprincs test* test3@mit.edu test2@mit.edu test1@mit.edu testuser@mit.edu kadmin: If no expression is provided, all principals are printed.  File: kerberos-admin.info, Node: Privileges, Next: Adding or Modifying Principals, Prev: Retrieving Information About a Principal, Up: Principals Privileges ---------- Administrative privileges for the Kerberos database are stored in the file `kadm5.acl'. Each line of the file contains a principal, the privileges that principal has, and optionally the target to which those permissions apply. The privileges are represented by single letters; UPPER-CASE letters represent negative permissions. The permissions are: a allows the addition of principals or policies in the database. A disallows the addition of principals or policies in the database. d allows the deletion of principals or policies in the database. D disallows the deletion of principals or policies in the database. m allows the modification of principals or policies in the database. M disallows the modification of principals or policies in the database. c allows the changing of passwords for principals in the database. C disallows the changing of passwords for principals in the database. i allows inquiries to the database. I disallows inquiries to the database. l allows the listing of principals or policies in the database. L disallows the listing of principals or policies in the database. * All privileges (admcil). x All privileges (admcil); identical to "*". Principals in this file can include the * wildcard. Here is an example of a `kadm5.acl' file. Note that order is important; permissions are determined by the first matching entry. */admin@ATHENA.MIT.EDU * joeadmin/null@ATHENA.MIT.EDU ADMCIL joeadmin/*@ATHENA.MIT.EDU il jennifer/root@ATHENA.MIT.EDU cil */root@ATHENA.MIT.EDU */*@ATHENA.MIT.EDU i In the above file, any principal with an `admin' instance has all administrative privileges. The user `joeadmin' has all permissions with his `admin' instance, `joeadmin/admin@ATHENA.MIT.EDU' (matches the first line). He has no permissions at all with his `null' instance, `joeadmin/null@ATHENA.MIT.EDU' (matches the second line). He has inquire and list permissions with any other instance (matches the third line). When `jennifer' is using her `root' instance, `jennifer/root@ATHENA.MIT.EDU', she has change password, inquire, and list privileges for any other principal that has the instance `root'. Finally, any principal in the realm `ATHENA.MIT.EDU' (except for `joeadmin/null@ATHENA.MIT.EDU', as mentioned above) has inquire privileges.  File: kerberos-admin.info, Node: Adding or Modifying Principals, Next: Deleting Principals, Prev: Privileges, Up: Principals Adding or Modifying Principals ------------------------------ To add a principal to the database, use the kadmin `add_principal' command, which requires the "add" administrative privilege. The syntax is: kadmin: add_principal [options] principal To modify attributes of a principal, use the kadmin `modify_principal' command, which requires the "modify" administrative privilege. The syntax is: kadmin: modify_principal [options] principal `add_principal' has the aliases `addprinc' and `ank'(1). `modify_principal' has the alias `modprinc'. The `add_principal' and `modify_principal' commands take the following switches: -salt salttype Uses the specified salt for generating the key. The valid salt types are: * full_name (aliases "v5_salt" and "normal"; this is the default) * name_only * realm_only * no_salt (alias "v4_salt") -clearpolicy removes the current policy from a principal (`modify_principal' only). -expire date Sets the expiration date of the principal to date. -pwexpire date Sets the expiration date of the password to date. -maxlife maxlife Sets the maximum ticket life of the principal to maxlife. -kvno number Explicity sets the key version number to number. MIT does not recommend doing this unless there is a specific reason. -policy policy Sets the policy used by this principal. (*Note Policies::.) If no policy is supplied, the principal will have no policy, and `kadmin' will print a warning message. {-|+}allow_postdated The "-allow_postdated" option prohibits this principal from obtaining postdated tickets. "+allow_postdated" clears this flag. In effect, "-allow_postdated" sets the KRB5_KDB_DISALLOW_POSTDATED flag on the principal in the database. {-|+}allow_forwardable The "-allow_forwardable" option prohibits this principal from obtaining forwardable tickets. "+allow_forwardable" clears this flag. In effect, "-allow_forwardable" sets the KRB5_KDB_DISALLOW_FORWARDABLE flag on the principal in the database. {-|+}allow_renewable The "-allow_renewable" option prohibits this principal from obtaining renewable tickets. "+allow_renewable" clears this flag. In effect, "-allow_renewable" sets the KRB5_KDB_DISALLOW_RENEWABLE flag on the principal in the database. {-|+}allow_proxiable The "-allow_proxiable" option prohibits this principal from obtaining proxiable tickets. "+allow_proxiable" clears this flag. In effect, "-allow_proxiable" sets the KRB5_KDB_DISALLOW_PROXIABLE flag. on the principal in the database. {-|+}allow_dup_skey The "-allow_dup_skey" option disables user-to-user authentication for this principal by prohibiting this principal from obtaining a session key for another user. "+allow_dup_skey" clears this flag. In effect, "-allow_dup_skey" sets the KRB5_KDB_DISALLOW_DUP_SKEY flag on the principal in the database. {-|+}requires_preauth The "+requires_preauth" option requires this principal to preauthenticate before being allowed to kinit. -requires_preauth clears this flag. In effect, +requires_preauth sets the KRB5_KDB_REQUIRES_PRE_AUTH flag on the principal in the database. {-|+}requires_hwauth The "+requires_hwauth" flag requires the principal to preauthenticate using a hardware device before being allowed to kinit. "-requires_hwauth" clears this flag. In effect, "+requires_hwauth" sets the KRB5_KDB_REQUIRES_HW_AUTH flag on the principal in the database. {-|+}allow_svr The "-allow_svr" flag prohibits the issuance of service tickets for this principal. "+allow_svr" clears this flag. In effect, "-allow_svr" sets the KRB5_KDB_DISALLOW_SVR flag on the principal in the database. {-|+}allow_tgs_req The "-allow_tgs_req" option specifies that a Ticket-Granting Service (TGS) request for a service ticket for this principal is not permitted. You will probably never need to use this option. "+allow_tgs_req" clears this flag. The default is "+allow_tgs_req". In effect, "-allow_tgs_req" sets the KRB5_KDB_DISALLOW_TGT_BASED flag on the principal in the database. {-|+}allow_tix The "-allow_tix" option forbids the issuance of any tickets for this principal. "+allow_tix" clears this flag. The default is "+allow_tix". In effect, "-allow_tix" sets the KRB5_KDB_DISALLOW_ALL_TIX flag on the principal in the database. {-|+}needchange The "+needchange" option sets a flag in attributes field to force a password change; "-needchange" clears it. The default is "-needchange". In effect, "+needchange" sets the KRB5_KDB_REQUIRES_PWCHANGE flag on the principal in the database. {-|+}password_changing_service The "+password_changing_service" option sets a flag in the attributes field marking this principal as a password change service. (Again, you will probably never need to use this option.) "-password_changing_service" clears the flag. The default is "-password_changing_service". In effect, the "+password_changing_service" option sets the KRB5_KDB_PWCHANGE_SERVICE flag on the principal in the database. -clearpolicy policyname Removes the policy policyname from the principal (`modify_principal' only). -randkey Sets the key for the principal to a random value (`add_principal' only). MIT recommends using this option for host keys. -pw password Sets the key of the principal to the specified string and does not prompt for a password (`add_principal' only). MIT does not recommend using this option. If you want to just use the default values, all you need to do is: kadmin: addprinc jennifer WARNING: no policy specified for "jennifer@ATHENA.MIT.EDU"; defaulting to no policy. Enter password for principal jennifer@ATHENA.MIT.EDU: <= Type the password. Re-enter password for principal jennifer@ATHENA.MIT.EDU: <=Type it again. Principal "jennifer@ATHENA.MIT.EDU" created. kadmin: If, on the other hand, you want to set up an account that expires on January 1, 2000, that uses a policy called "stduser", with a temporary password (which you want the user to change immediately), you would type the following. (Note: each line beginning with => is a continuation of the previous line.) kadmin: addprinc david -expire "1/1/2000 12:01am EST" -policy stduser => +needchange Enter password for principal david@ATHENA.MIT.EDU: <= Type the password. Re-enter password for principal david@ATHENA.MIT.EDU: <= Type it again. Principal "david@ATHENA.MIT.EDU" created. kadmin: If you will need cross-realm authentication, you need to add principals for the other realm's TGT to each realm. For example, if you need to do cross-realm authentication between the realms ATHENA.MIT.EDU and FUBAR.ORG, you would need to add the principals `krbtgt/FUBAR.ORG@ATHENA.MIT.EDU' and `krbtgt/ATHENA.MIT.EDU@FUBAR.ORG' to both databases. You need to be sure the passwords and the key version numbers (kvno) are the same in both databases. This may require explicitly setting the kvno with the `-kvno' option. ---------- Footnotes ---------- (1) `ank' was the short form of the equivalent command using the deprecated `kadmin5' database administrative tool. It has been kept  File: kerberos-admin.info, Node: Deleting Principals, Next: Changing Passwords, Prev: Adding or Modifying Principals, Up: Principals Deleting Principals ------------------- To delete a principal, use the kadmin `delete_principal' command, which requires the "delete" administrative privilege. The syntax is: delete_principal [-force] principal `delete_principal' has the alias `delprinc'. The `-force' option causes `delete_principal' not to ask if you're sure. For example: kadmin: delprinc jennifer Are you sure you want to delete the principal "jennifer@ATHENA.MIT.EDU"? (yes/no): yes Principal "jennifer@ATHENA.MIT.EDU" deleted. Make sure that you have removed this principal from all ACLs before reusing. kadmin:  File: kerberos-admin.info, Node: Changing Passwords, Next: Renaming Principals, Prev: Deleting Principals, Up: Principals Changing Passwords ------------------ To change a principal's password use the kadmin `change_password' command, which requires the "modify" administrative privilege (unless the principal is changing his/her own password). The syntax is: change_password [options] principal The `change_password' option has the alias `cpw'. `change_password' takes the following options: -salt salttype Uses the specified salt for generating the key. Salt types are the same as for the `add_principal' command (*note Adding or Modifying Principals::.). -randkey Sets the key of the principal to a random value. -pw password Sets the password to the string password. MIT does not recommend using this option. For example: kadmin: cpw david Enter password for principal david@ATHENA.MIT.EDU: <= Type the new password. Re-enter password for principal david@ATHENA.MIT.EDU: <= Type it again. Password for david@ATHENA.MIT.EDU changed. kadmin: Note that `change_password' will not let you change the password to one that is in the principal's password history.  File: kerberos-admin.info, Node: Renaming Principals, Prev: Changing Passwords, Up: Principals Renaming Principals ------------------- To rename a principal, use the kadmin `rename_principal' command, which requires both the "add" and "delete" administrative privileges. The syntax is: rename_principal [-force] old_principal new_principal The `rename_principal' command has the alias `renprinc'. For example: kadmin: renprinc test test0 Are you sure you want to rename the principal "test@ATHENA.MIT.EDU" to "test0@ATHENA.MIT.EDU"? (yes/no): yes Principal "test@ATHENA.MIT.EDU" renamed to "test0@ATHENA.MIT.EDU". Make sure that you have removed "test@ATHENA.MIT.EDU" from all ACLs before reusing. kadmin:  File: kerberos-admin.info, Node: Policies, Next: Dumping a Kerberos Database to a File, Prev: Principals, Up: Administrating Kerberos Database Entries Policies ======== A policy is a set of rules governing passwords. Policies can dictate minimum and maximum password lifetimes, minimum number of characters and character classes a password must contain, and the number of old passwords kept in the database. * Menu: * Retrieving Policies:: * Retrieving the List of Policies:: * Adding or Modifying Policies:: * Deleting Policies::  File: kerberos-admin.info, Node: Retrieving Policies, Next: Retrieving the List of Policies, Prev: Policies, Up: Policies Retrieving Policies ------------------- To retrieve a policy, use the kadmin `get_policy' command, which requires the "inquire" administrative privilege. The syntax is: get_policy [-terse] policy The `get_policy' command has the alias `getpol'. For example: kadmin: get_policy admin Policy: admin Maximum password life: 180 days 00:00:00 Minimum password life: 00:00:00 Minimum password length: 6 Minimum number of password character classes: 2 Number of old keys kept: 5 Reference count: 17 kadmin: The "reference count" is the number of principals using that policy. The `get_policy' command has a `-terse' option, which lists each field as a quoted, tab-separated string. For example: kadmin: get_policy -terse admin admin 15552000 0 6 2 5 17 kadmin:  File: kerberos-admin.info, Node: Retrieving the List of Policies, Next: Adding or Modifying Policies, Prev: Retrieving Policies, Up: Policies Retrieving the List of Policies ------------------------------- You can retrieve the list of policies with the kadmin `list_policies' command, which requires the "list" privilege. The syntax is: list_policies [expression] where expression is a shell-style glob expression that can contain the characters *, ?, and []. All policy names matching the expression are displayed. The `list_policies' command has the alias `listpols'. For example: kadmin: listpols test-pol dict-only once-a-min test-pol-nopw kadmin: listpols t* test-pol test-pol-nopw kadmin:  File: kerberos-admin.info, Node: Adding or Modifying Policies, Next: Deleting Policies, Prev: Retrieving the List of Policies, Up: Policies Adding or Modifying Policies ---------------------------- To add a new policy, use the kadmin `add_policy' command, which requires the "add" administrative privilege. The syntax is: add_policy [options] policy_name To modify attributes of a principal, use the kadmin `modify_policy' command, which requires the "modify" administrative privilege. The syntax is: modify_policy [options] policy_name `add_policy' has the alias `addpol'. `modify_poilcy' has the alias `modpol'. The `add_policy' and `modify_policy' commands take the following switches: -maxlife time Sets the maximum lifetime of a password to time. -minlife time Sets the minimum lifetime of a password to time. -minlength length Sets the minimum length of a password to length characters. -minclasses number Requires at least number of character classes in a password. -history number Sets the number of past keys kept for a principal to number.  File: kerberos-admin.info, Node: Deleting Policies, Prev: Adding or Modifying Policies, Up: Policies Deleting Policies ----------------- To delete a policy, use the `kadmin' `delete_policy' command, which requires the "delete" administrative privilege. The syntax is: delete_policy policy_name The `delete_policy' command has the alias `delpol'. It prompts for confirmation before deletion. For example: kadmin: delete_policy guests Are you sure you want to delete the policy "guests"? (yes/no): yes Policy "guests" deleted. kadmin: Note that you must cancel the policy from all principals before deleting it. The `delete_policy' command will fail if it is in use by any principals.  File: kerberos-admin.info, Node: Dumping a Kerberos Database to a File, Next: Restoring a Kerberos Database from a Dump File, Prev: Policies, Up: Administrating Kerberos Database Entries Dumping a Kerberos Database to a File ===================================== To dump a Kerberos database into a file, use the `kdb5_util' `dump' command on one of the KDCs. The syntax is: kdb5_util dump [-old] [-b6] [-ov] [-verbose] [filename [principals...]] The `kdb5_util dump' command takes the following options: -old causes the dump to be in the Kerberos 5 Beta 5 and earlier dump format ("kdb5_edit load_dump version 2.0"). -b6 causes the dump to be in the Kerberos 5 Beta 6 format ("kdb5_edit load_dump version 3.0"). -ov causes the dump to be in ovsec_adm_export format. -verbose causes the name of each principal and policy to be printed as it is dumped. For example: shell% kdb5_util dump dumpfile shell% shell% kbd5_util dump -verbose dumpfile kadmin/admin@ATHENA.MIT.EDU krbtgt/ATHENA.MIT.EDU@ATHENA.MIT.EDU kadmin/history@ATHENA.MIT.EDU K/M@ATHENA.MIT.EDU kadmin/changepw@ATHENA.MIT.EDU shell% If you specify which principals to dump, you must use the full principal, as in the following example. (The line beginning with => is a continuation of the previous line.): shell% kdb5_util dump -verbose dumpfile K/M@ATHENA.MIT.EDU => kadmin/admin@ATHENA.MIT.EDU kadmin/admin@ATHENA.MIT.EDU K/M@ATHENA.MIT.EDU shell% Otherwise, the principals will not match those in the database and will not be dumped: shell% kdb5_util dump -verbose dumpfile K/M kadmin/admin shell% If you do not specify a dump file, `kdb5_util' will dump the database to the standard output.  File: kerberos-admin.info, Node: Restoring a Kerberos Database from a Dump File, Next: Creating a Stash File, Prev: Dumping a Kerberos Database to a File, Up: Administrating Kerberos Database Entries Restoring a Kerberos Database from a Dump File ============================================== To restore a Kerberos database dump from a file, use the `kdb5_util' `load' command on one of the KDCs. The syntax is: kdb5_util load [-old] [-b6] [-ov] [-verbose] [-update] dumpfilename dbname [admin_dbname] The `kdb5_util load' command takes the following options: -old requires the dump to be in the Kerberos 5 Beta 5 and earlier dump format ("kdb5_edit load_dump version 2.0"). -b6 requires the dump to be in the Kerberos 5 Beta 6 format ("kdb5_edit load_dump version 3.0"). -ov requires the dump to be in ovsec_adm_export format. -verbose causes the name of each principal and policy to be printed as it is dumped. -update causes records from the dump file to be updated in or added to the existing database. For example: shell% kdb5_util load dumpfile principal shell% shell% kdb5_util load -update dumpfile principal shell% If the database file exists, and the -update flag was not given, `kdb5_util' will overwrite the existing database.  File: kerberos-admin.info, Node: Creating a Stash File, Next: Creating and Destroying a Kerberos Database, Prev: Restoring a Kerberos Database from a Dump File, Up: Administrating Kerberos Database Entries Creating a Stash File ===================== A stash file allows a KDC to authenticate itself to the database utilities, such as `kadmin', `kadmind', `krb5kdc', and `kdb5_util'. To create a stash file, use the `kdb5_util' `stash' command. The syntax is: kdb5_util stash [-f keyfile] For example: shell% kdb5_util stash kdb5_util: Cannot find/read stored master key while reading master key kdb5_util: Warning: proceeding without master key Enter KDC database master key: <= Type the KDC database master password. shell% If you do not specify a stash file, `kdb5_util' will stash the key in the file specified in your `kdc.conf' file.  File: kerberos-admin.info, Node: Creating and Destroying a Kerberos Database, Prev: Creating a Stash File, Up: Administrating Kerberos Database Entries Creating and Destroying a Kerberos Database =========================================== If you need to create a new Kerberos database, use the `kdb5_util' `create' command. The syntax is: kdb5_util create [-s] If you specify the `-s' option, `kdb5_util' will stash a copy of the master key in a stash file. (*Note Creating a Stash File::.) For example: shell% /usr/krb5/sbin/kdb5_util -r ATHENA.MIT.EDU create -s kdb5_util: No such file or directory while setting active database to '/krb5/principal' Initializing database '/usr/krb5/lib/krb5kdc/principal' for => realm 'ATHENA.MIT.EDU', master key name 'K/M@ATHENA.MIT.EDU' You will be prompted for the database Master Password. It is important that you NOT FORGET this password. Enter KDC database master key: <= Type the master password. Re-enter KDC database master key to verify: <= Type it again. shell%  File: kerberos-admin.info, Node: Application Servers, Next: Backups of Secure Hosts, Prev: Administrating Kerberos Database Entries, Up: Top Application Servers ******************* If you need to install the Kerberos V5 programs on an application server, please refer to the Kerberos V5 Installation Guide. Once you have installed the software, you need to add that host to the Kerberos database (*note Adding or Modifying Principals::.), and generate a "keytab" for that host, that contains the host's key. You also need to make sure the host's clock is within your maximum clock skew of the KDCs. * Menu: * Keytabs:: * Clock Skew:: * Getting DNS Information Correct:: * Configuring Your Firewall to Work With Kerberos V5::