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This document describes how to convert to Kerberos V5 from Kerberos V4.

* Menu:

* Copyright::
* Introduction::
* Configuration Files::
* Upgrading KDCs::
* Upgrading Application Servers::
* Upgrading Client machines::
* Firewall Considerations::


File: krb425.info,  Node: Copyright,  Next: Introduction,  Prev: Top,  Up: Top

Copyright
*********

Copyright (C) 1985-2001 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.  Furthermore if you
modify this software you must label your software as modified software
and not distribute it in such a fashion that it might be confused with
the original MIT software.  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.

The following copyright and permission notice applies to the OpenVision
Kerberos Administration system located in kadmin/create, kadmin/dbutil,
kadmin/passwd, kadmin/server, lib/kadm5, and portions of lib/rpc:

     Copyright, OpenVision Technologies, Inc., 1996, All Rights Reserved

     WARNING:  Retrieving the OpenVision Kerberos Administration system
     source code, as described below, indicates your acceptance of the
     following terms.  If you do not agree to the following terms, do
     not retrieve the OpenVision Kerberos administration system.

     You may freely use and distribute the Source Code and Object Code
     compiled from it, with or without modification, but this Source
     Code is provided to you "AS IS" EXCLUSIVE OF ANY WARRANTY,
     INCLUDING, WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY
     OR FITNESS FOR A PARTICULAR PURPOSE, OR ANY OTHER WARRANTY,
     WHETHER EXPRESS OR IMPLIED.  IN NO EVENT WILL OPENVISION HAVE ANY
     LIABILITY FOR ANY LOST PROFITS, LOSS OF DATA OR COSTS OF
     PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, OR FOR ANY SPECIAL,
     INDIRECT, OR CONSEQUENTIAL DAMAGES ARISING OUT OF THIS AGREEMENT,
     INCLUDING, WITHOUT LIMITATION, THOSE RESULTING FROM THE USE OF THE
     SOURCE CODE, OR THE FAILURE OF THE SOURCE CODE TO PERFORM, OR FOR
     ANY OTHER REASON.

     OpenVision retains all copyrights in the donated Source Code.
     OpenVision also retains copyright to derivative works of the
     Source Code, whether created by OpenVision or by a third party.
     The OpenVision copyright notice must be preserved if derivative
     works are made based on the donated Source Code.

     OpenVision Technologies, Inc. has donated this Kerberos
     Administration system to MIT for inclusion in the standard
     Kerberos 5 distribution.  This donation underscores our commitment
     to continuing Kerberos technology development and our gratitude
     for the valuable work which has been performed by MIT and the
     Kerberos community.

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.


File: krb425.info,  Node: Introduction,  Next: Configuration Files,  Prev: Copyright,  Up: Top

Introduction
************

As with most software upgrades, Kerberos V5 is generally backward
compatible but not necessarily forward compatible.  The Kerberos V5
daemons can interoperate with Kerberos V4 clients, but most of the
Kerberos V4 daemons can not interoperate with Kerberos V5 clients.  This
suggests the following strategy for performing the upgrade:

  1. *Upgrade your KDCs.*  This is must be done first, so that
     interactions with the Kerberos database, whether by Kerberos V5
     clients or by Kerberos V4 clients, will succeed.

  2. *Upgrade your servers.*  This must be done before upgrading client
     machines, so that the servers are able to respond to both Kerberos
     V5 and Kerberos V4 queries.

  3. *Upgrade your client machines.*  Do this only after your KDCs and
     application servers are upgraded, so that all of your Kerberos V5
     clients will be talking to Kerberos V5 daemons.


File: krb425.info,  Node: Configuration Files,  Next: Upgrading KDCs,  Prev: Introduction,  Up: Top

Configuration Files
*******************

The Kerberos `krb5.conf' and KDC `kdc.conf' configuration files allow
additional tags for Kerberos V4 compatibility.

* Menu:

* krb5.conf::
* kdc.conf::


File: krb425.info,  Node: krb5.conf,  Next: kdc.conf,  Prev: Configuration Files,  Up: Configuration Files

krb5.conf
=========

If you used the defaults, both when you installed Kerberos V4 and when
you installed Kerberos V5, you should not need to include any of these
tags.  However, some or all of them may be necessary for nonstandard
installations.

* Menu:

* libdefaults::
* realms (krb5.conf)::


File: krb425.info,  Node: libdefaults,  Next: realms (krb5.conf),  Prev: krb5.conf,  Up: krb5.conf

[libdefaults]
-------------

In the [libdefaults] section, the following additional tags may be used:

krb4_srvtab
     Specifies the location of the Kerberos V4 srvtab file.  Default is
     `/etc/srvtab'.

krb4_config
     Specifies the location of the Kerberos V4 configuration file.
     Default is `/etc/krb.conf'.

krb4_realms
     Specifies the location of the Kerberos V4 domain/realm translation
     file.  Default is `/etc/krb.realms'.


File: krb425.info,  Node: realms (krb5.conf),  Prev: libdefaults,  Up: krb5.conf

[realms]
--------

In the [realms] section, the following Kerberos V4 tags may be used:
default_domain
     Identifies the default domain for hosts in this realm.  This is
     needed for translating V4 principal names (which do not contain a
     domain name) to V5 principal names.  The default is your Kerberos
     realm name, converted to lower case.

v4_instance_convert
     This subsection allows the administrator to configure exceptions
     to the default_domain mapping rule.  It contains V4 instances (tag
     name) which should be translated to some specific hostname (tag
     value) as the second component in a Kerberos V5 principal name.

v4_realm
     This relation allows the administrator to configure a different
     realm name to be used when converting V5 principals to V4 ones.
     This should only be used when running separate V4 and V5 realms,
     with some external means of password sychronization between the
     realms.


File: krb425.info,  Node: kdc.conf,  Prev: krb5.conf,  Up: Configuration Files

kdc.conf
========

Because Kerberos V4 requires a different type of salt for the encryption
type, you will need to change the `supported_enctypes' line in the
[realms] section to:

     supported_enctypes = des-cbc-crc:normal des-cbc-crc:v4

This is the only change needed to the `kdc.conf' file.


File: krb425.info,  Node: Upgrading KDCs,  Next: Upgrading Application Servers,  Prev: Configuration Files,  Up: Top

Upgrading KDCs
**************

To convert your KDCs from Kerberos V4 to Kerberos V5, do the following:

  1. Install Kerberos V5 on each KDC, according to the instructions in
     the Kerberos V5 Installation Guide, up to the point where it tells
     you to create the database.

  2. Find the `kadmind' (V4) daemon process on the master KDC and kill
     it.  This will prevent changes to the Kerberos database while you
     convert the database to the new Kerberos V5 format.

  3. Create a dump of the V4 database in the directory where your V5
     database will reside by issuing the command:

          % kdb_util dump /usr/local/var/krb5kdc/v4-dump

  4. Load the V4 dump into a Kerberos V5 database, by issuing the
     command:

          % kdb5_util load_v4 v4-dump

  5. Create a Kerberos V5 stash file, if desired, by issuing the
     command:

          % kdb5_util stash

  6. Proceed with the rest of the Kerberos V5 installation as described
     in the Kerberos V5 Installation Guide.  When you get to the section
     that tells you to start the `krb5kdc' and `kadmind' daemons, first
     find and kill the Kerberos V4 `kerberos' daemon on each of the
     KDCs.  Then start the `krb5kdc' and `kadmind' daemons as directed.
     Finally, start the Kerberos V5 to V4 ticket translator daemon,
     `krb524d', by issuing the command:

          % /usr/local/sbin/krb524d -m > /dev/null &

     If you have a stash file and you start the `krb5kdc' and `kadmind'
     daemons at boot time, you should add the above line to your
     `/etc/rc' (or `/etc/rc.local') file on each KDC.


File: krb425.info,  Node: Upgrading Application Servers,  Next: Upgrading Client machines,  Prev: Upgrading KDCs,  Up: Top

Upgrading Application Servers
*****************************

Install Kerberos V5 on each application server, according to the
instructions in the Kerberos V5 Installation Guide, with the following
exceptions:

   * In the file `/etc/services', add or edit the lines described in the
     Kerberos V5 Installation Guide, with the following exception:

     in place of:

          kerberos      88/udp    kdc    # Kerberos V5 KDC
          kerberos      88/tcp    kdc    # Kerberos V5 KDC

     add instead:

          kerberos-sec  88/udp    kdc    # Kerberos V5 KDC
          kerberos-sec  88/tcp    kdc    # Kerberos V5 KDC

   * In the file `/etc/inetd.conf', for a *secure* server, instead of
     making the changes described in the Kerberos V5 Installation
     Guide, do the following:

     Find and comment out any lines for the services `ftp', `telnet',
     `shell', `login', and `exec'.

     Add the following lines.  (Note:  each line beginning with => is a
     continuation of the previous line.)

          klogin  stream  tcp  nowait  root
          =>    /usr/local/sbin/klogind  klogind -k -c
          eklogin stream  tcp  nowait  root
          n=>   /usr/local/sbin/klogind  klogind -k -c -e
          kshell  stream  tcp  nowait  root
          =>    /usr/local/sbin/kshd  kshd -k -c -A
          ftp     stream  tcp  nowait  root
          =>    /usr/local/sbin/ftpd  ftpd -a
          telnet  stream  tcp  nowait  root
          =>    /usr/local/sbin/telnetd  telnetd -a valid

     *N.B.*: As noted in the Kerberos V5 Installation Guide, if you
     have some clients running older versions of Kerberos V5 (beta 6 or
     earlier), checksums were done differently in those versions, which
     will cause authentication to fail.  To get around this problem,
     have the `klogind' and `kshd' daemons ignore checksums, by
     replacing each `-c' flag above with `-i'.

     For an *insecure* server, make the changes described in the
     Kerberos V5 Installation Guide.

     When you make changes to `inetd.conf', remember to `kill -HUP' the
     `inetd' process to cause the changes to take effect.

   * Convert your Kerberos V4 srvtab file to Kerberos V5 keytab file as
     follows:

          # /usr/local/sbin/ktutil
          ktutil:  rst /etc/krb-srvtab
          ktutil:  wkt /etc/krb5.keytab
          ktutil:  q
          #


File: krb425.info,  Node: Upgrading Client machines,  Next: Firewall Considerations,  Prev: Upgrading Application Servers,  Up: Top

Upgrading Client machines
*************************

Install Kerberos V5 on each client machine, according to the
instructions in the Kerberos V5 Installation Guide.

Tell your users to add the appropriate directory to their paths.  On
UNIX machines, this will probably be `/usr/local/bin'.

Note that if you upgrade your client machines before all of your
application servers are upgraded, your users will need to use the
Kerberos V4 programs to connect to application servers that are still
running Kerberos V4.  (The one exception is the UNIX version of
Kerberos V5 telnet, which can connect to a Kerberos V4 and Kerberos V5
application servers.)  Users can use either the Kerberos V4 or Kerberos
V5 programs to connect to Kerberos V5 servers.


File: krb425.info,  Node: Firewall Considerations,  Prev: Upgrading Client machines,  Up: Top

Firewall Considerations
***********************

Kerberos V5 uses port 88, which is the port assigned by the IETF, for
KDC requests.  Kerberos V4 used port 750.  If your users will need to
get to any KDCs outside your firewall, you will need to allow TCP and
UDP requests on port 88 for your users to get to off-site Kerberos V5
KDCs, and on port 750 for your users to get to off-site Kerberos V4
KDCs.



Tag Table:
Node: Top102
Node: Copyright428
Node: Introduction5465
Node: Configuration Files6486
Node: krb5.conf6785
Node: libdefaults7192
Node: realms (krb5.conf)7742
Node: kdc.conf8784
Node: Upgrading KDCs9164
Node: Upgrading Application Servers10884
Node: Upgrading Client machines13376
Node: Firewall Considerations14259

End Tag Table
