This is krb5-install.info, produced by makeinfo version 4.5 from
install.texinfo.

INFO-DIR-SECTION Kerberos
START-INFO-DIR-ENTRY
* krb5-install: (krb5-install).         Kerberos V5 Installation Guide
END-INFO-DIR-ENTRY


File: krb5-install.info,  Node: Start the Kerberos Daemons,  Prev: Create a kadmind Keytab (optional),  Up: Install the Master KDC

Start the Kerberos Daemons on the Master KDC
............................................

At this point, you are ready to start the Kerberos daemons on the Master
KDC.  To do so, type:

     shell% /usr/local/sbin/krb5kdc
     shell% /usr/local/sbin/kadmind

Each daemon will fork and run in the background.  Assuming you want
these daemons to start up automatically at boot time, you can add them
to the KDC's `/etc/rc' or `/etc/inittab' file.  You need to have a
stash file in order to do this.

You can verify that they started properly by checking for their startup
messages in the logging locations you defined in `/etc/krb5.conf'.
(*Note Edit the Configuration Files::.)  For example:

     shell% tail /var/log/krb5kdc.log
     Dec 02 12:35:47 beeblebrox krb5kdc[3187](info): commencing operation
     shell% tail /var/log/kadmin.log
     Dec 02 12:35:52 beeblebrox kadmind[3189](info): starting

Any errors the daemons encounter while starting will also be listed in
the logging output.


File: krb5-install.info,  Node: Install the Slave KDCs,  Next: Back on the Master KDC,  Prev: Install the Master KDC,  Up: Installing KDCs

Install the Slave KDCs
----------------------

You are now ready to start configuring the slave KDCs.  Assuming you are
setting the KDCs up so that you can easily switch the master KDC with
one of the slaves, you should perform each of these steps on the master
KDC as well as the slave KDCs, unless these instructions specify
otherwise.

* Menu:

* Create Host Keys for the Slave KDCs::
* Extract Host Keytabs for the KDCs::
* Set Up the Slave KDCs for Database Propagation::


File: krb5-install.info,  Node: Create Host Keys for the Slave KDCs,  Next: Extract Host Keytabs for the KDCs,  Prev: Install the Slave KDCs,  Up: Install the Slave KDCs

Create Host Keys for the Slave KDCs
...................................

Each KDC needs a host principal in the Kerberos database.  You can enter
these from any host, once the `kadmind' daemon is running.  For
example, if your master KDC were called kerberos.mit.edu, and you had
two KDC slaves named kerberos-1.mit.edu and kerberos-2.mit.edu, you
would type the following:

     shell% /usr/local/sbin/kadmin
     kadmin: addprinc -randkey host/kerberos.mit.edu
     NOTICE: no policy specified for "host/kerberos.mit.edu@ATHENA.MIT.EDU";
     assigning "default"
     Principal "host/kerberos.mit.edu@ATHENA.MIT.EDU" created.
     kadmin: addprinc -randkey host/kerberos-1.mit.edu
     NOTICE: no policy specified for "host/kerberos-1.mit.edu@ATHENA.MIT.EDU";
     assigning "default"
     Principal "host/kerberos-1.mit.edu@ATHENA.MIT.EDU" created.
     kadmin: addprinc -randkey host/kerberos-2.mit.edu
     NOTICE: no policy specified for "host/kerberos-2.mit.edu@ATHENA.MIT.EDU";
     assigning "default"
     Principal "host/kerberos-2.mit.edu@ATHENA.MIT.EDU" created.
     kadmin:

It is not actually necessary to have the master KDC server in the
Kerberos database, but it can be handy if:

   * anyone will be logging into the machine as something other than
     root

   * you want to be able to swap the master KDC with one of the slaves
     if necessary.


File: krb5-install.info,  Node: Extract Host Keytabs for the KDCs,  Next: Set Up the Slave KDCs for Database Propagation,  Prev: Create Host Keys for the Slave KDCs,  Up: Install the Slave KDCs

Extract Host Keytabs for the KDCs
.................................

Each KDC (including the master) needs a keytab to decrypt tickets.
Ideally, you should extract each keytab locally on its own KDC.  If this
is not feasible, you should use an encrypted session to send them across
the network.  To extract a keytab on a KDC called kerberos.mit.edu, you
would execute the following command:

     kadmin: ktadd host/kerberos.mit.edu
     kadmin: Entry for principal host/kerberos.mit.edu@ATHENA.MIT.EDU with
          kvno 1, encryption type DES-CBC-CRC added to keytab
          WRFILE:/etc/krb5.keytab.
     kadmin:

Note that the principal must exist in the Kerberos database in order to
extract the keytab.


File: krb5-install.info,  Node: Set Up the Slave KDCs for Database Propagation,  Prev: Extract Host Keytabs for the KDCs,  Up: Install the Slave KDCs

Set Up the Slave KDCs for Database Propagation
..............................................

The database is propagated from the master KDC to the slave KDCs via the
`kpropd' daemon.  To set up propagation, create a file on each KDC,
named `/usr/local/var/krb5kdc/kpropd.acl', containing the principals
for each of the KDCs.  For example, if the master KDC were
`kerberos.mit.edu', the slave KDCs were `kerberos-1.mit.edu' and
`kerberos-2.mit.edu', and the realm were `ATHENA.MIT.EDU', then the
file's contents would be:

     host/kerberos.mit.edu@ATHENA.MIT.EDU
     host/kerberos-1.mit.edu@ATHENA.MIT.EDU
     host/kerberos-2.mit.edu@ATHENA.MIT.EDU

Then, add the following line to `/etc/inetd.conf' file on each KDC:

     krb5_prop stream tcp nowait root /usr/local/sbin/kpropd kpropd

You also need to add the following lines to `/etc/services' on each KDC:

     kerberos        88/udp      kdc       # Kerberos authentication (udp)
     kerberos        88/tcp      kdc       # Kerberos authentication (tcp)
     krb5_prop       754/tcp               # Kerberos slave propagation
     kerberos-adm    749/tcp               # Kerberos 5 admin/changepw (tcp)
     kerberos-adm    749/udp               # Kerberos 5 admin/changepw (udp)


File: krb5-install.info,  Node: Back on the Master KDC,  Next: Finish Installing the Slave KDCs,  Prev: Install the Slave KDCs,  Up: Installing KDCs

Back on the Master KDC
----------------------

Now that the slave KDCs are able to accept database propagation, you'll
need to propagate the database to each of them.

* Menu:

* Propagate the Database to Each Slave KDC::


File: krb5-install.info,  Node: Propagate the Database to Each Slave KDC,  Prev: Back on the Master KDC,  Up: Back on the Master KDC

Propagate the Database to Each Slave KDC
........................................

First, create a dump of the database on the master KDC, as follows:

     shell% /usr/local/sbin/kdb5_util dump /usr/local/var/krb5kdc/slave_datatrans
     shell%

Next, you need to manually propagate the database to each slave KDC, as
in the following example.  (The lines beginning with => are
continuations of the previous line.):

     /usr/local/sbin/kprop -f /usr/local/var/krb5kdc/slave_datatrans
     => kerberos-1.mit.edu
     /usr/local/sbin/kprop -f /usr/local/var/krb5kdc/slave_datatrans
     => kerberos-2.mit.edu

You will need a script to dump and propagate the database.  The
following is an example of a bourne shell script that will do this.
(Note that the line that begins with => is a continuation of the
previous line.  Remember that you need to replace /usr/local with the
name of the directory in which you installed Kerberos V5.)

     #!/bin/sh
     
     kdclist = "kerberos-1.mit.edu kerberos-2.mit.edu"
     
     /usr/local/sbin/kdb5_util "dump
     => /usr/local/var/krb5kdc/slave_datatrans"
     
     for kdc in $kdclist
     do
     /usr/local/sbin/kprop -f /usr/local/var/krb5kdc/slave_datatrans $kdc
     done

You will need to set up a cron job to run this script at the intervals
you decided on earlier (*Note Database Propagation::.)


File: krb5-install.info,  Node: Finish Installing the Slave KDCs,  Next: Add Kerberos Principals to the Database,  Prev: Back on the Master KDC,  Up: Installing KDCs

Finish Installing the Slave KDCs
--------------------------------

Now that the slave KDCs have copies of the Kerberos database, you can
create stash files for them and start the `krb5kdc' daemon.

* Menu:

* Create Stash Files on the Slave KDCs::
* Start the krb5kdc Daemon on Each KDC::


File: krb5-install.info,  Node: Create Stash Files on the Slave KDCs,  Next: Start the krb5kdc Daemon on Each KDC,  Prev: Finish Installing the Slave KDCs,  Up: Finish Installing the Slave KDCs

Create Stash Files on the Slave KDCs
....................................

Create stash files, by issuing the following commands on each slave KDC:

     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:  <= Enter the database master key.
     shell%

As mentioned above, the stash file is necessary for your KDCs to be able
authenticate to themselves, such as when they reboot.  You could run
your KDCs without stash files, but you would then need to type in the
Kerberos database master key by hand every time you start a KDC daemon.


File: krb5-install.info,  Node: Start the krb5kdc Daemon on Each KDC,  Prev: Create Stash Files on the Slave KDCs,  Up: Finish Installing the Slave KDCs

Start the krb5kdc Daemon on Each KDC
....................................

The final step in configuing your slave KDCs is to run the KDC daemon:

     shell% /usr/local/sbin/krb5kdc

As with the master KDC, you will probably want to add this command to
the KDCs' `/etc/rc' or `/etc/inittab' files, so they will start the
krb5kdc daemon automatically at boot time.


File: krb5-install.info,  Node: Add Kerberos Principals to the Database,  Next: Limit Access to the KDCs,  Prev: Finish Installing the Slave KDCs,  Up: Installing KDCs

Add Kerberos Principals to the Database
---------------------------------------

Once your KDCs are set up and running, you are ready to use `kadmin' to
load principals for your users, hosts, and other services into the
Kerberos database.  This procedure is described fully in the "Adding or
Modifying Principals" section of the Kerberos V5 System Administrator's
Guide.  (*Note Create Host Keys for the Slave KDCs::, for a brief
description.)  The keytab is generated by running `kadmin' and issuing
the `ktadd' command.


File: krb5-install.info,  Node: Limit Access to the KDCs,  Next: Switching Master and Slave KDCs,  Prev: Add Kerberos Principals to the Database,  Up: Installing KDCs

Limit Access to the KDCs
------------------------

To limit the possibility that your Kerberos database could be
compromised, MIT recommends that each KDC be a dedicated host, with
limited access.  If your KDC is also a file server, FTP server, Web
server, or even just a client machine, someone who obtained root access
through a security hole in any of those areas could gain access to the
Kerberos database.


File: krb5-install.info,  Node: Switching Master and Slave KDCs,  Next: Incremental Database Propagation,  Prev: Limit Access to the KDCs,  Up: Installing KDCs

Switching Master and Slave KDCs
-------------------------------

You may occasionally want to use one of your slave KDCs as the master.
This might happen if you are upgrading the master KDC, or if your master
KDC has a disk crash.

Assuming you have configured all of your KDCs to be able to function as
either the master KDC or a slave KDC (as this document recommends), all
you need to do to make the changeover is:

If the master KDC is still running, do the following on the _old_
master KDC:

  1. Kill the `kadmind' process.

  2. Disable the cron job that propagates the database.

  3. Run your database propagation script manually, to ensure that the
     slaves all have the latest copy of the database.  (*Note Propagate
     the Database to Each Slave KDC::.)  If there is a need to preserve
     per-principal policy information from the database, you should do
     a "kdb5_util dump -ov" in order to preserve that information and
     propogate that dump file securely by some means to the slave so
     that its database has the correct state of the per-principal
     policy information.

On the _new_ master KDC:

  1. Create a database keytab.  (*Note Create a kadmind Keytab
     (optional)::.)

  2. Start the `kadmind' daemon.  (*Note Start the Kerberos Daemons::.)

  3. Set up the cron job to propagate the database.  (*Note Propagate
     the Database to Each Slave KDC::.)

  4. Switch the CNAMEs of the old and new master KDCs.  (If you don't do
     this, you'll need to change the `krb5.conf' file on every client
     machine in your Kerberos realm.)



File: krb5-install.info,  Node: Incremental Database Propagation,  Prev: Switching Master and Slave KDCs,  Up: Installing KDCs

Incremental Database Propagation
--------------------------------

At some very large sites, dumping and transmitting the database can
take more time than is desirable for changes to propagate from the
master KDC to the slave KDCs.  The incremental propagation support
added in the 1.7 release is intended to address this.

With incremental propagation enabled, all programs on the master KDC
that change the database also write information about the changes to an
"update log" file, maintained as a circular buffer of a certain size.
A process on each slave KDC connects to a service on the master KDC
(currently implmented in the `kadmind' server) and periodically
requests the changes that have been made since the last check.  By
default, this check is done every two minutes.  If the database has
just been modified in the previous several seconds (currently the
threshold is hard-coded at 10 seconds), the slave will not retrieve
updates, but instead will pause and try again soon after.  This reduces
the likelihood that incremental update queries will cause delays for an
administrator trying to make a bunch of changes to the database at the
same time.

Incremental propagation uses the following entries in the per-realm
data in the KDC config file:

`iprop_enable' (boolean)
     If this is set to `true', then incremental propagation is enabled,
     and (as noted below) normal `kprop' propagation is disabled.  The
     default is `false'.

`iprop_master_ulogsize' (integer)
     This indicates the number of entries that should be retained in the
     update log.  The default is 1000; the maximum number is 2500.

`iprop_slave_poll' (time interval)
     This indicates how often the slave should poll the master KDC for
     changes to the database.  The default is two minutes.

`iprop_port' (integer)
     This specifies the port number to be used for incremental
     propagation.  This is required in both master and slave
     configuration files.

`iprop_logfile' (file name)
     This specifies where the update log file for the realm database is
     to be stored.  The default is to use the `database_name' entry from
     the `realms' section of the config file, with `.ulog' appended.
     (NOTE: If `database_name' isn't specified in the `realms' section,
     perhaps because the LDAP database back end is being used, or the
     file name is specified in the `dbmodules' section, then the
     hard-coded default for `database_name' is used.  Determination of
     the `iprop_logfile' default value will not use values from the
     `dbmodules' section.)

Both master and slave sides must have principals named
`kiprop/HOSTNAME' (where HOSTNAME is, as usual, the lower-case,
fully-qualified, canonical name for the host) registered and keys
stored in the default keytab file (`/etc/krb5.keytab').

On the master KDC side, the `kiprop/HOSTNAME' principal must be listed
in the `kadmind' ACL file `kadm5.acl', and given the `p' privilege.

On the slave KDC side, `kpropd' should be run.  When incremental
propagation is enabled, it will connect to the `kadmind' on the master
KDC and start requesting updates.

The normal `kprop' mechanism is disabled by the incremental propagation
support.  However, if the slave has been unable to fetch changes from
the master KDC for too long (network problems, perhaps), the log on the
master may wrap around and overwrite some of the updates that the slave
has not yet retrieved.  In this case, the slave will instruct the
master KDC to dump the current database out to a file and invoke a
one-time `kprop' propagation, with special options to also convey the
point in the update log at which the slave should resume fetching
incremental updates.  Thus, all the keytab and ACL setup previously
described for `kprop' propagation is still needed.

There are several known bugs and restrictions in the current
implementation:
   * The "call out to `kprop'" mechanism is a bit fragile; if the
     `kprop' propagation fails to connect for some reason, the process
     on the slave may hang waiting for it, and will need to be
     restarted.

   * The master and slave must be able to initiate TCP connections in
     both directions, without an intervening NAT.  They must also be
     able to communicate over IPv4, since MIT's kprop and RPC code does
     not currently support IPv6.

* Menu:

* Sun/MIT Incremental Propagation Differences::


File: krb5-install.info,  Node: Sun/MIT Incremental Propagation Differences,  Prev: Incremental Database Propagation,  Up: Incremental Database Propagation

Sun/MIT Incremental Propagation Differences
...........................................

Sun donated the original code for supporting incremental database
propagation to MIT.  Some changes have been made in the MIT source tree
that will be visible to administrators.  (These notes are based on
Sun's patches.  Changes to Sun's implementation since then may not be
reflected here.)

The Sun config file support looks for `sunw_dbprop_enable',
`sunw_dbprop_master_ulogsize', and `sunw_dbprop_slave_poll'.

The incremental propagation service is implemented as an ONC RPC
service.  In the Sun implementation, the service is registered with
`rpcbind' (also known as `portmapper') and the client looks up the port
number to contact.  In the MIT implementation, where interaction with
some modern versions of `rpcbind' doesn't always work well, the port
number must be specified in the config file on both the master and
slave sides.

The Sun implementation hard-codes pathnames in `/var/krb5' for the
update log and the per-slave `kprop' dump files.  In the MIT
implementation, the pathname for the update log is specified in the
config file, and the per-slave dump files are stored in
`/usr/local/var/krb5kdc/slave_datatrans_HOSTNAME'.


File: krb5-install.info,  Node: Installing and Configuring UNIX Client Machines,  Next: UNIX Application Servers,  Prev: Installing KDCs,  Up: Installing Kerberos V5

Installing and Configuring UNIX Client Machines
===============================================

Client machine installation is much more straightforward than
installation of the KDCs.

* Menu:

* Client Programs::
* Client Machine Configuration Files::


File: krb5-install.info,  Node: Client Programs,  Next: Client Machine Configuration Files,  Prev: Installing and Configuring UNIX Client Machines,  Up: Installing and Configuring UNIX Client Machines

Client Programs
---------------

The Kerberized client programs are `kinit', `klist', `kdestroy',
`kpasswd', and `ksu'.  All of these programs are in the directory
`/usr/local/bin'.

MIT recommends that you use `login.krb5' in place of `/bin/login' to
give your users a single-sign-on system.  You will need to make sure
your users know to use their Kerberos passwords when they log in.

You will also need to educate your users to use the ticket management
programs `kinit', `klist', `kdestroy', and to use the Kerberos programs
`ksu' and `kpasswd' in place of their non-Kerberos counterparts `su'
and `passwd'.


File: krb5-install.info,  Node: Client Machine Configuration Files,  Prev: Client Programs,  Up: Installing and Configuring UNIX Client Machines

Client Machine Configuration Files
----------------------------------

Each machine running Kerberos must have a `/etc/krb5.conf' file.
(*Note krb5.conf::.)

Also, for most UNIX systems, you must add the appropriate Kerberos
services to each client machine's `/etc/services' file.  If you are
using the default configuration for Kerberos V5, you should be able to
just insert the following code:

     kerberos      88/udp    kdc    # Kerberos V5 KDC
     kerberos      88/tcp    kdc    # Kerberos V5 KDC
     kerberos-adm  749/tcp          # Kerberos 5 admin/changepw
     kerberos-adm  749/udp          # Kerberos 5 admin/changepw
     krb5_prop     754/tcp          # Kerberos slave propagation
     krb524        4444/tcp         # Kerberos 5 to 4 ticket translator

* Menu:

* Mac OS X Configuration::


File: krb5-install.info,  Node: Mac OS X Configuration,  Prev: Client Machine Configuration Files,  Up: Client Machine Configuration Files

Mac OS X Configuration
......................

To install Kerberos V5 on Mac OS X and Mac OS X Server, follow the
directions for generic Unix-based OS's, except for the `/etc/services'
updates described above.

Mac OS X and Mac OS X Server use a database called NetInfo to store the
contents of files normally found in `/etc'.  Instead of modifying
`/etc/services', you should run the following commands to add the
Kerberos service entries to NetInfo:

     $ niutil -create . /services/kerberos
     $ niutil -createprop . /services/kerberos name kerberos kdc
     $ niutil -createprop . /services/kerberos port 750
     $ niutil -createprop . /services/kerberos protocol tcp udp
     $ niutil -create . /services/krbupdate
     $ niutil -createprop . /services/krbupdate name krbupdate kreg
     $ niutil -createprop . /services/krbupdate port 760
     $ niutil -createprop . /services/krbupdate protocol tcp
     $ niutil -create . /services/kpasswd
     $ niutil -createprop . /services/kpasswd name kpasswd kpwd
     $ niutil -createprop . /services/kpasswd port 761
     $ niutil -createprop . /services/kpasswd protocol tcp
     $ niutil -create . /services/klogin
     $ niutil -createprop . /services/klogin port 543
     $ niutil -createprop . /services/klogin protocol tcp
     $ niutil -create . /services/eklogin
     $ niutil -createprop . /services/eklogin port 2105
     $ niutil -createprop . /services/eklogin protocol tcp
     $ niutil -create . /services/kshell
     $ niutil -createprop . /services/kshell name kshell krcmd
     $ niutil -createprop . /services/kshell port 544
     $ niutil -createprop . /services/kshell protocol tcp

In addition to adding services to NetInfo, you must also modify the
resolver configuration in NetInfo so that the machine resolves its own
hostname as a FQDN (fully qualified domain name).  By default, Mac OS X
and Mac OS X Server machines query NetInfo to resolve hostnames before
falling back to DNS.  Because NetInfo has an unqualified name for all
the machines in the NetInfo database, the machine's own hostname will
resolve to an unqualified name.  Kerberos needs a FQDN to look up keys
in the machine's keytab file.

Fortunately, you can change the `lookupd' caching order to query DNS
first.  Run the following NetInfo commands and reboot the machine:

     $ niutil -create . /locations/lookupd/hosts
     $ niutil -createprop . /locations/lookupd/hosts LookupOrder CacheAgent DNSAgent
      NIAgent NILAgent

Once you have rebooted, you can verify that the resolver now behaves
correctly.  Compile the Kerberos 5 distribution and run:

     $ cd .../src/tests/resolve
     $ ./resolve

This will tell you whether or not your machine returns FQDNs on name
lookups.  If the test still fails, you can also try turning off DNS
caching.  Run the following commands and reboot:

     $ niutil -create . /locations/lookupd/hosts
     $ niutil -createprop . /locations/lookupd/hosts LookupOrder DNSAgent
      CacheAgent NIAgent NILAgent

The remainder of the setup of a Mac OS X client machine or application
server should be the same as for other UNIX-based systems.


File: krb5-install.info,  Node: UNIX Application Servers,  Prev: Installing and Configuring UNIX Client Machines,  Up: Installing Kerberos V5

UNIX Application Servers
========================

An application server is a host that provides one or more services over
the network.  Application servers can be "secure" or "insecure."  A
"secure" host is set up to require authentication from every client
connecting to it.  An "insecure" host will still provide Kerberos
authentication, but will also allow unauthenticated clients to connect.

If you have Kerberos V5 installed on all of your client machines,
MIT recommends that you make your hosts secure, to take advantage of
the security that Kerberos authentication affords.  However, if you
have some clients that do not have Kerberos V5 installed, you can run
an insecure server, and still take advantage of Kerberos V5's single
sign-on capability.

* Menu:

* The Keytab File::
* Some Advice about Secure Hosts::


File: krb5-install.info,  Node: The Keytab File,  Next: Some Advice about Secure Hosts,  Prev: UNIX Application Servers,  Up: UNIX Application Servers

The Keytab File
---------------

All Kerberos server machines need a "keytab" file, called
`/etc/krb5.keytab', to authenticate to the KDC.  The keytab file is an
encrypted, local, on-disk copy of the host's key.  The keytab file,
like the stash file (*Note Create the Database::) is a potential
point-of-entry for a break-in, and if compromised, would allow
unrestricted access to its host.  The keytab file should be readable
only by root, and should exist only on the machine's local disk.  The
file should not be part of any backup of the machine, unless access to
the backup data is secured as tightly as access to the machine's root
password itself.

In order to generate a keytab for a host, the host must have a principal
in the Kerberos database.  The procedure for adding hosts to the
database is described fully in the "Adding or Modifying Principals"
section of the `Kerberos V5 System Administrator's Guide'.  *Note
Create Host Keys for the Slave KDCs::. for a brief description.)  The
keytab is generated by running `kadmin' and issuing the `ktadd' command.

For example, to generate a keytab file to allow the host
trillium.mit.edu to authenticate for the services `host', `ftp', and
`pop', the administrator `joeadmin' would issue the command (on
trillium.mit.edu):

     trillium% /usr/local/sbin/kadmin
     kadmin5: ktadd host/trillium.mit.edu ftp/trillium.mit.edu
     => pop/trillium.mit.edu
     kadmin: Entry for principal host/trillium.mit.edu@ATHENA.MIT.EDU with
     kvno 3, encryption type DES-CBC-CRC added to keytab
     WRFILE:/etc/krb5.keytab.
     kadmin: Entry for principal ftp/trillium.mit.edu@ATHENA.MIT.EDU with
     kvno 3, encryption type DES-CBC-CRC added to keytab
     WRFILE:/etc/krb5.keytab.
     kadmin: Entry for principal pop/trillium.mit.edu@ATHENA.MIT.EDU with
     kvno 3, encryption type DES-CBC-CRC added to keytab
     WRFILE:/etc/krb5.keytab.
     kadmin5: quit
     trillium%

If you generate the keytab file on another host, you need to get a copy
of the keytab file onto the destination host (`trillium', in the above
example) without sending it unencrypted over the network.


File: krb5-install.info,  Node: Some Advice about Secure Hosts,  Prev: The Keytab File,  Up: UNIX Application Servers

Some Advice about Secure Hosts
------------------------------

Kerberos V5 can protect your host from certain types of break-ins, but
it is possible to install Kerberos V5 and still leave your host
vulnerable to attack.  Obviously an installation guide is not the place
to try to include an exhaustive list of countermeasures for every
possible attack, but it is worth noting some of the larger holes and how
to close them.

We recommend that backups of secure machines exclude the keytab file
(`/etc/krb5.keytab').  If this is not possible, the backups should at
least be done locally, rather than over a network, and the backup tapes
should be physically secured.

The keytab file and any programs run by root, including the Kerberos V5
binaries, should be kept on local disk.  The keytab file should be
readable only by root.


File: krb5-install.info,  Node: Upgrading Existing Kerberos V5 Installations,  Next: Bug Reports for Kerberos V5,  Prev: Installing Kerberos V5,  Up: Top

Upgrading Existing Kerberos V5 Installations
********************************************

If you already have an existing Kerberos database that you created with
a prior release of Kerberos 5, you can upgrade it to work with the
current release with the `kdb5_util' command.  It is only necessary to
perform this dump/undump procedure if you were running a krb5-1.0.x KDC
and are migrating to a krb5-1.1.x or newer KDC or if you were running a
krb5-1.1.x KDC and are migrating to a krb5-1.2.x or newer KDC.  The
process for upgrading a Master KDC involves the following steps:

  1. Stop your current KDC and administration server processes, if any.

  2. Dump your existing Kerberos database to an ASCII file with
     `kdb5_util''s "dump" command:

          shell% cd /usr/local/var/krb5kdc
          shell% kdb5_util dump old-kdb-dump
          shell% kdb5_util dump -ov old-kdb-dump.ov
          shell%

  3. Create a new Master KDC installation (*Note Install the Master
     KDC::.).  If you have a stash file for your current database,
     choose any new master password but then copy your existing stash
     file to the location specified by your kdc.conf; if you do not
     have a stash file for your current database, you must choose the
     same master password.

  4. Load your old Kerberos database into the new system with
     `kdb5_util''s "load" command:

          shell% cd /usr/local/var/krb5kdc
          shell% kdb5_util load old-kdb-dump
          shell% kdb5_util load -update old-kdb-dump.ov
          shell%


The "dump -ov" and "load -update" commands are necessary in order to
preserve per-principal policy information, since the default dump format
filters out that information.  If you omit those steps, the loaded
database database will lose the policy information for each principal
that has a policy.

To update a Slave KDC, you must stop the old server processes on the
Slave KDC, install the new server binaries, reload the most recent slave
dump file, and re-start the server processes.

* Menu:

* Upgrading to Triple-DES and RC4 Encryption Keys::


File: krb5-install.info,  Node: Upgrading to Triple-DES and RC4 Encryption Keys,  Prev: Upgrading Existing Kerberos V5 Installations,  Up: Upgrading Existing Kerberos V5 Installations

Upgrading to Triple-DES Encryption Keys
=======================================

Beginning with the 1.2 release from MIT, Kerberos includes a stronger
encryption algorithm called "triple DES" - essentially, three
applications of the basic DES encryption algorithm, greatly increasing
the resistance to a brute-force search for the key by an attacker.
This algorithm is more secure, but encryption is much slower.

Release 1.1 had some support for triple-DES service keys, but with
release 1.2 we have added support for user keys and session keys as
well.  Release 1.0 had very little support for multiple cryptosystems,
and some of that software may not function properly in an environment
using triple-DES as well as plain DES.

In the 1.3 release from MIT, Kerberos also includes the RC4 encryption
alogorithm, a stream cipher symmetric key algorithm developed in 1987
by Ronald Rivest at RSA Data Security.  Please note that RC4 is not
part of the IETF standard.

Because of the way the MIT Kerberos database is structured, the KDC
will assume that a service supports only those encryption types for
which keys are found in the database.  Thus, if a service has only a
single-DES key in the database, the KDC will not issue tickets for that
service that use triple-DES or RC4 session keys; it will instead issue
only single-DES session keys, even if other services are already
capable of using triple-DES or RC4.  So if you make sure your
application server software is updated before adding a triple-DES or
RC4 key for the service, clients should be able to talk to services at
all times during the updating process.

Normally, the listed `supported_enctypes' in `kdc.conf' are all used
when a new key is generated.  You can control this with command-line
flags to `kadmin' and `kadmin.local'.  You may want to exclude
triple-DES and RC4 by default until you have updated a lot of your
application servers, and then change the default to include triple-DES
and RC4.  We recommend that you always include `des-cbc-crc' in the
default list.


File: krb5-install.info,  Node: Bug Reports for Kerberos V5,  Prev: Upgrading Existing Kerberos V5 Installations,  Up: Top

Bug Reports for Kerberos V5
***************************

In any complex software, there will be bugs.  If you have successfully
built and installed Kerberos V5, please use the `krb5-send-pr' program
to fill out a Problem Report should you encounter any errors in our
software.

Bug reports that include proposed fixes are especially welcome.  If you
do include fixes, please send them using either context diffs or unified
diffs (using `diff -c' or `diff -u', respectively).  Please be careful
when using "cut and paste" or other such means to copy a patch into a
bug report; depending on the system being used, that can result in
converting TAB characters into spaces, which makes applying the patches
more difficult.

The `krb5-send-pr' program is installed in the directory
`/usr/local/sbin'.

The `krb5-send-pr' program enters the problem report into our Problem
Report Management System (PRMS), which automatically assigns it to the
engineer best able to help you with problems in the assigned category.

The `krb5-send-pr' program will try to intelligently fill in as many
fields as it can.  You need to choose the "category", "class",
"severity", and "priority" of the problem, as well as giving us as much
information as you can about its exact nature.

The PR category will be one of:

     krb5-admin   krb5-appl    krb5-build   krb5-clients
     krb5-doc     krb5-kdc     krb5-libs    krb5-misc
     pty          telnet       test

Choose the category that best describes the area under which your
problem falls.

The class can be "sw-bug", "doc-bug", "change-request", or "support".
The first two are exactly as their names imply.  Use change-request
when the software is behaving according to specifications, but you want
to request changes in some feature or behavior.  The support class is
intended for more general questions about building or using Kerberos V5.

The severity of the problem indicates the problem's impact on the
usability of Kerberos V5.  If a problem is "critical", that means the
product, component or concept is completely non-operational, or some
essential functionality is missing, and no workaround is known.  A
"serious" problem is one in which the product, component or concept is
not working properly or significant functionality is missing.  Problems
that would otherwise be considered critical are rated serious when a
workaround is known.  A "non-critical" problem is one that is indeed a
problem, but one that is having a minimal effect on your ability to use
Kerberos V5.  E.g., The product, component or concept is working in
general, but lacks features, has irritating behavior, does something
wrong, or doesn't match its documentation.  The default severity is
serious.

The priority indicates how urgent this particular problem is in
relation to your work.  Note that low priority does not imply low
importance.  A priority of "high" means a solution is needed as soon as
possible.  A priority of "medium" means the problem should be solved no
later than the next release.  A priority of "low" means the problem
should be solved in a future release, but it is not important to your
work how soon this happens.  The default priority is medium.

Note that a given severity does not necessarily imply a given priority.
For example, a non-critical problem might still have a high priority if
you are faced with a hard deadline.  Conversely, a serious problem might
have a low priority if the feature it is disabling is one that you do
not need.

It is important that you fill in the release field and tell us what
changes you have made, if any.

A sample filled-out form from a company named "Toasters, Inc." might
look like this:

     To: krb5-bugs@mit.edu
     Subject: misspelled "Kerberos" in title of installation guide
     From: jcb
     Reply-To: jcb
     Cc:
     X-send-pr-version: 3.99
     
     
     >Submitter-Id:	mit
     >Originator:	Jeffrey C. Gilman Bigler
     >Organization:
     mit
     >Confidential:	no
     >Synopsis:	Misspelled "Kerberos" in title of installation guide
     >Severity:	non-critical
     >Priority:	low
     >Category:	krb5-doc
     >Class:		doc-bug
     >Release:	1.0-development
     >Environment:
     	<machine, os, target, libraries (multiple lines)>
     System: ULTRIX imbrium 4.2 0 RISC
     Machine: mips
     >Description:
             Misspelled "Kerberos" in title of "Kerboros V5 Installation Guide"
     >How-To-Repeat:
             N/A
     >Fix:
             Correct the spelling.

If the `krb5-send-pr' program does not work for you, or if you did not
get far enough in the process to have an installed and working
`krb5-send-pr', you can generate your own form, using the above as an
example.


