\input texinfo @c -*-texinfo-*-
@c %**start of header
@setfilename install.info
@settitle Kerberos V5
@c For double-sided printing, uncomment:
@setchapternewpage odd
@c %**end of header
@set EDITION BETA 6
@set VERSION BETA 6
@set UPDATED Mar 20, 1996
@ignore
@iftex
@finalout
@end iftex
@end ignore
@ifinfo
This file documents how to build and install the Kerberos V5
distribution.
Copyright (C) 1995, 1996 Massachusetts Institute of Technology.
All Rights Reserved.
Export of this software 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 any necessary licenses 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.
Athena(r), Hesiod(r), Moira(r), and Discuss(r) are registered trademarks of
the Massachusetts Institute of Technology (MIT). Project Athena, Athena
Dashboard, Athena MUSE, Kerberos, X Window System, and Zephyr are trademarks
of MIT. No commercial use of these trademarks may be made without prior
written permission of MIT.
All other product names are trademarks of their respective companies.
@end ifinfo
@titlepage
@title Kerberos V5
@subtitle Notes on Building and Installing Kerberos
@subtitle Edition @value{EDITION}, for Kerberos version @value{VERSION}
@subtitle @value{UPDATED}
@author by Theodore Ts'o
@page
@vskip 0pt plus 1filll
Copyright @copyright{} 1995, 1996 Massachusetts Institute of Technology
All Rights Reserved.
Export of this software 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 any necessary licenses 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.
Athena(r), Hesiod(r), Moira(r), and Discuss(r) are registered trademarks of
the Massachusetts Institute of Technology (MIT). Project Athena, Athena
Dashboard, Athena MUSE, Kerberos, X Window System, and Zephyr are trademarks
of MIT. No commercial use of these trademarks may be made without prior
written permission of MIT.
All other product names are trademarks of their respective companies.
@end titlepage
@node Top, Introduction, (dir), (dir)
@comment node-name, next, previous, up
@ifinfo
This file documents how to build and install the Kerberos V5
distribution.
This is edition @value{EDITION}, for Kerberos V5 version @value{VERSION}.
@end ifinfo
@c The master menu is updated using emacs19's M-x texinfo-all-menus-update
@c function. Don't forget to run M-x texinfo-every-node-update after
@c you add a new section or subsection, or after you've rearranged the
@c order of sections or subsections. Also, don't forget to add an @node
@c command before each @section or @subsection! All you need to enter
@c is:
@c
@c @node New Section Name
@c @section New Section Name
@c
@c M-x texinfo-every-node-update will take care of calculating the
@c node's forward and back pointers.
@c
@menu
* Introduction::
* How Kerberos Works::
* Building Kerberos::
* Installation::
* Troubleshooting::
--- The Detailed Node Listing ---
How Kerberos Works: A Schematic Description
* Network Services::
* Kerberos Tickets::
* The Kerberos Database::
* Kerberos Realms::
* The Ticket-Granting Ticket::
* Network Services and the Master Database::
* The User-Kerberos Interaction::
Network Services and the Master Database
* The Keytab File::
Building Kerberos
* Build Requirements:: How much disk space, etc. you need to
build Kerberos.
* Unpacking the Sources:: Preparing the source tree.
* Doing the Build:: Compiling Kerberos.
* Testing the Build:: Making sure Kerberos built correctly.
* Options to Configure::
* osconf.h::
* Shared Library Support::
* OS Incompatibilities:: Special cases to watch for.
* Using Autoconf:: Modifying Kerberos V5's
configuration scripts.
Doing the Build
* Building Within a Single Tree::
* Building with Separate Build Directories::
* Building using lndir::
Testing the Build
* The DejaGnu Tests::
Shared Library Support
* Shared Library Theory::
* NetBSD Shared Library Support::
* AIX Shared Library Support::
* Solaris 5.3 Shared Library Support::
* Alpha OSF/1 Shared Library Support::
Operating System Incompatibilities
* Ultrix 4.2/3::
* Alpha OSF/1 V1.3::
* Alpha OSF/1 V2.0++::
* BSDI::
* Solaris versions 2.0 through 2.3::
* Solaris 2.X::
* SGI Irix 5.X::
Installation
* Background::
* Installation on any Machine::
* Installing the KDC::
* Migrating from V4 to V5 Kerberos::
* A Sample Application::
* Installing Kerberos Applications::
* Common Kerberos Service Names::
Installation on any Machine
* Picking a Realm Name::
* Configuration files::
* Recommended Programs::
Configuration files
* krb5.conf::
* Converting V4 configuration files::
* /etc/services::
Installing the KDC
* kdc.conf::
* Initializing the KDB::
* Storing the Master Password::
* Adding Users to the Database::
* Starting the Kerberos Server::
* Setting up Slave Kerberos Servers::
* Inter-realm Kerberos Operation::
* The Administration Server::
* Testing the Kerberos Server::
Setting up Slave Kerberos Servers
* Kerberos Slave Database Propagation::
* Installing a Slave Server::
A Sample Application
* Installing the Sample Application::
* Testing the Sample Server::
Installing Kerberos Applications
* Levels of Security::
* Preparing a Workstation for Kerberos Application Servers::
* BSD Utilities::
* Telnet and FTP::
BSD Utilities
* Checksums:: Checksum facility for dealing with active attacks.
* BSD Utility Configuration Example:: Sample @file{inetd.conf} entries for BSD utilities.
@end menu
@node Introduction, How Kerberos Works, Top, Top
@chapter Introduction
This document describes the procedures necessary to compile Kerberos V5
from the source distribution, and then to install it at a particular
site. The reader is assumed to be familiar with C/UNIX development
tools.
In any complex software, there will be bugs. Please send bug reports
or other problems you may uncover to the e-mail address
@b{krb5-bugs@@mit.edu}. Please mention which version of the Kerberos
V5 distribution you are using, and whether you have made any private
changes. 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 @samp{diff -c} or @samp{diff
-u}, respectively).
Please note that there are still a number of aspects of Kerberos V5
which will likely change before the 1.0 release.
As these changes occur, we will update the documentation accordingly.
@c As of this release, all the databases, including the aname to localname
@c ones now use version 1.85 of the Berkeley DB code. This may imply
@c database conversions for those running earlier releases of Kerberos
@c V5. We recommend that you dump your database with the old kdb5_edit and
@c restore with the new one.
@node How Kerberos Works, Building Kerberos, Introduction, Top
@chapter How Kerberos Works: A Schematic Description
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 @i{Kerberos: An Authentication
Service for Open Network Systems}, a paper presented at Winter USENIX
1988, in Dallas, Texas.
@menu
* Network Services::
* Kerberos Tickets::
* The Kerberos Database::
* Kerberos Realms::
* The Ticket-Granting Ticket::
* Network Services and the Master Database::
* The User-Kerberos Interaction::
@end menu
@node Network Services, Kerberos Tickets, How Kerberos Works, How Kerberos Works
@section Network Services and Their Client Programs
In an environment that provides network services, you use @dfn{client}
programs to request service from @dfn{server} programs that are
somewhere on the network. Suppose you have logged in to a workstation
and you want to @samp{rlogin} to another machine. You use the local
@samp{rlogin} client program to contact the remote machine's
@samp{rlogind} daemon.
@node Kerberos Tickets, The Kerberos Database, Network Services, How Kerberos Works
@section Kerberos Tickets
Under Kerberos, the @samp{rlogind} daemon allows you to login to a
remote machine if you can provide @samp{rlogind} 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.
@node The Kerberos Database, Kerberos Realms, Kerberos Tickets, How Kerberos Works
@section The Kerberos Database
Kerberos will give you credentials only if you have an entry in the Kerberos
server's @dfn{Kerberos database}. Your database entry includes your
Kerberos @dfn{principal} (which is often just your username), and
your Kerberos password. Every Kerberos user must have an entry in this
database.
@node Kerberos Realms, The Ticket-Granting Ticket, The Kerberos Database, How Kerberos Works
@section Kerberos Realms
Each site (or administrative domain within a site) will have their own
Kerberos database, which contains information about the users and
services for that particular site or administrative domain.
A @dfn{Kerberos Realm} is used to distinguish the users and services in
one particular area of administrative control from another area of
administrative control.
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 @dfn{slave servers},
which have read-only copies of the Kerberos database which are
periodically propagated from the master server. For more details on how
this is done, see @ref{Setting up Slave Kerberos Servers}.
@node The Ticket-Granting Ticket, Network Services and the Master Database, Kerberos Realms, How Kerberos Works
@section The Ticket-Granting Ticket
The @samp{kinit} command prompts for your password, and if you enter
it successfully, you will obtain a @dfn{ticket-granting ticket} and a
@dfn{ticket session key} which gives you the right to use the ticket.
This combination of the ticket and its associated key is also known as
your @dfn{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 @dfn{credentials cache}, which is often
simply just a file in @file{/tmp}. The credentials cache is also
referred to as the @dfn{ticket file}, especially in Kerberos V4
documentation. It should be noted, however, that a credentials cache
does not have to be stored in a file.
@node Network Services and the Master Database, The User-Kerberos Interaction, The Ticket-Granting Ticket, How Kerberos Works
@section 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, @samp{laughter.mit.edu}, that requires Kerberos
authentication from anyone who wants to @samp{rlogin} to it. The host's
Kerberos realm is @samp{ATHENA.MIT.EDU}.
This service must be registered in the Kerberos database, using the
proper service name, which in this case is
@samp{host/laughter.mit.edu@@ATHENA.MIT.EDU}. The @kbd{/} character
separates the various @dfn{components} of the Kerberos principal; the
@kbd{@@} character separates the realm name from the rest of the
principal name. The first component, @samp{host}, denotes the name or
type of the service that is being offered: generic host-level access to
the machine. The second component, @samp{laughter.mit.edu}, names the
specific machine which is offering this service. There will generally
be many different machines, each offering one particular type of
service, and the second component serves to give each one of these
servers a different Kerberos name.
@menu
* The Keytab File::
@end menu
@node The Keytab File, , Network Services and the Master Database, Network Services and the Master Database
@subsection The Keytab File
For each service, there must also be a @dfn{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 the @dfn{Key
tables}, or @dfn{keytab files}. (Keytab files were previously
referred to as @dfn{srvtab files} in the V4 literature.) The service
keys that are used by services which run as root are often stored in
the file @file{/etc/v5srvtab}.
@b{WARNING:} 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.
@node The User-Kerberos Interaction, , Network Services and the Master Database, How Kerberos Works
@section The User--Kerberos Interaction
Suppose that you (in the guise of a general user) walk up to a workstation
intending to login to it, and then @samp{rlogin} to the machine @samp{laughter}.
Here's what happens:
@enumerate
@item
You login to the workstation and use the @samp{kinit} command
to get a ticket-granting ticket.
This command prompts you for your Kerberos password. (On some systems
which have a modified @samp{/bin/login} program, this may be done as
part of the login process, not requiring the user to run a separate
program.)
@enumerate A
@item
The @samp{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.
@item
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 @samp{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 @samp{KRB5_CCNAME} environment variable. If
this variable is not set, the name of the file will be
@file{/tmp/krb5cc_<uid>}, where <uid> is your UNIX user-id, represented
in decimal format.
@end enumerate
@item
Now you use the @samp{rlogin} client to access the machine
@samp{laughter}.
@example
host% @b{rlogin laughter}
@end example
@enumerate A
@item
The @samp{rlogin} client checks your ticket file to see if you
have a ticket for the @samp{host} service for @samp{laughter}.
You don't, so @samp{rlogin} uses the credential cache's ticket-granting
ticket to make a request to the master server's ticket-granting service.
@item
This ticket-granting service receives the
@samp{host/laughter.mit.edu} request and looks in the master database
for an @samp{host/laughter.mit.edu} entry. If the entry exists, the
ticket-granting service issues you a ticket for that service. That
ticket is also cached in your credentials cache.
@item
The @samp{rlogin} client now sends that ticket to
the @samp{laughter} @samp{rlogind} 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 the ticket is valid and you are allowed
to login to @samp{laughter} (because the your name matches one in
/etc/passwd, or you are in the @file{.k5login} file), you will find
yourself logged into the machine.
@end enumerate
@end enumerate
@node Building Kerberos, Installation, How Kerberos Works, Top
@chapter Building Kerberos
Starting with the Beta 4 distribution, we are using a new configuration
system, which was built using the Free Software Foundation's
@samp{autoconf} program. This system will hopefully make Kerberos V5
much simpler to build and reduce the amount of effort required in
porting Kerberos V5 to a new platform.
@menu
* Build Requirements:: How much disk space, etc. you need to
build Kerberos.
* Unpacking the Sources:: Preparing the source tree.
* Doing the Build:: Compiling Kerberos.
* Testing the Build:: Making sure Kerberos built correctly.
* Options to Configure::
* osconf.h::
* Shared Library Support::
* OS Incompatibilities:: Special cases to watch for.
* Using Autoconf:: Modifying Kerberos V5's
configuration scripts.
@end menu
@node Build Requirements, Unpacking the Sources, Building Kerberos, Building Kerberos
@section Build Requirements
In order to build Kerberos V5, you will need approximately 60-70
megabytes of disk space. The exact amount will vary depending on the
platform and whether the distribution is compiled with debugging symbol
tables or not.
If you wish to keep a separate @dfn{build tree}, which contains the compiled
@file{*.o} file and executables, separate from your source tree, you
will need a @samp{make} program which supports @samp{VPATH}, or
you will need to use a tool such as @samp{lndir} to produce a symbolic
link tree for your build tree.
@node Unpacking the Sources, Doing the Build, Build Requirements, Building Kerberos
@section Unpacking the Sources
The first step in each of these build procedures is to unpack the source
distribution. The Kerberos V5 distribution comes in two compressed tar
files. The first file, which is generally named @file{krb5.src.tar.gz},
contains the sources for all of Kerberos except for the crypto library,
which is found in the file @file{krb5.crypto.tar.gz}.
Both files should be unpacked in the same directory, such as
@file{/u1/krb5}. (In the rest of this document, we will assume that you
have chosen to unpack the Kerberos V5 source distribution in this
directory.)
@node Doing the Build, Testing the Build, Unpacking the Sources, Building Kerberos
@section Doing the Build
You have a number of different options in how to build Kerberos. If you
only need to build Kerberos for one platform, using a single directory
tree which contains both the source files and the object files is the
simplest. However, if you need to maintain Kerberos for a large number
of platforms, you will probably want to use separate build trees for
each platform. We recommend that you look at see @ref{OS
Incompatibilities} for notes that we have on particular operating
systems.
@menu
* Building Within a Single Tree::
* Building with Separate Build Directories::
* Building using lndir::
@end menu
@node Building Within a Single Tree, Building with Separate Build Directories, Doing the Build, Doing the Build
@subsection Building Within a Single Tree
If you don't want separate build trees for each architecture, then
use the following abbreviated procedure.
@enumerate
@item
@code{cd /u1/krb5/src}
@item
@code{./configure}
@item
@code{make}
@end enumerate
That's it!
@node Building with Separate Build Directories, Building using lndir, Building Within a Single Tree, Doing the Build
@subsection Building with Separate Build Directories
If you wish to keep separate build directories for each platform, you
can do so using the following procedure. (Note, this requires that your
@samp{make} program support @samp{VPATH}. GNU's make will provide this
functionality, for example.) If your @samp{make} program does not
support this, see the next section.
For example, if you wish to create a build directory for @code{pmax} binaries
you might use the following procedure:
@enumerate
@item
@code{mkdir /u1/krb5/pmax}
@item
@code{cd /u1/krb5/pmax}
@item
@code{../src/configure}
@item
@code{make}
@end enumerate
@node Building using lndir, , Building with Separate Build Directories, Doing the Build
@subsection Building Using @samp{lndir}
If you wish to keep separate build directories for each platform, and
you do not have access to a @samp{make} program which supports @samp{VPATH},
all is not lost. You can use the @samp{lndir} program to create
symbolic link trees in your build directory.
For example, if you wish to create a build directory for solaris binaries
you might use the following procedure:
@enumerate
@item
@code{mkdir /u1/krb5/solaris}
@item
@code{cd /u1/krb5/solaris}
@item
@code{/u1/krb5/src/util/lndir `pwd`/../src}
@item
@code{./configure}
@item
@code{make}
@end enumerate
You must give an absolute pathname to @samp{lndir} because it has a bug that
makes it fail for relative pathnames. Note that this version differs
from the latest version as distributed and installed by the XConsortium
with X11R6. Either version should be acceptable.
@node Testing the Build, Options to Configure, Doing the Build, Building Kerberos
@section Testing the Build
The Kerberos V5 distribution comes with built-in regression tests. To
run them, simply type the following command while in the top-level build
directory (i.e., the directory where you sent typed @samp{make} to start
building Kerberos; see @ref{Doing the Build}.):
@example
% make check
@end example
@menu
* The DejaGnu Tests::
@end menu
@node The DejaGnu Tests, , Testing the Build, Testing the Build
@subsection The DejaGnu Tests
Some of the built-in regression tests are setup to use the DejaGnu
framework for running tests. These tests tend to be more comprehensive
than the normal built-in tests as they setup test servers and test
client/server activities.
DejaGnu may be found wherever GNU software is archived.
Most of the tests are setup to run as a non-privledged user. There are
two series of tests (@samp{rlogind} and @samp{telnetd}) which require
the ability to @samp{rlogin} as root to the local machine. Admittedly,
this does require the use of a @file{.rhosts} file or some other
authenticated means. @footnote{If you are fortunate enough to have a
previous version of Kerberos V5 or V4 installed, and the Kerberos rlogin
is first in your path, you can setup @file{.k5login} or @file{.klogin}
respectively to allow you access.}
If you cannot obtain root access to your machine, all the other tests
will still run. Note however, with DejaGnu 1.2, the "untested testcases"
will cause the testsuite to exit with a non-zero exit status which
@samp{make} will consider a failure of the testing process. Do not worry
about this, as these tests are the last run when @samp{make check} is
executed from the top level of the build tree.
@node Options to Configure, osconf.h, Testing the Build, Building Kerberos
@section Options to Configure
There are a number of options to @samp{configure} which you can use to
control how the Kerberos distribution is built. The following table
lists the most commonly used options to Kerberos V5's @samp{configure}
program.
@table @code
@item --help
Provides help to configure. This will list the set of commonly used
options for building Kerberos.
@item --prefix=DIR
By default, Kerberos will install the package's files rooted at
`/usr/local' as in `/usr/local/bin', `/usr/local/sbin', etc. If you
desire a different location use this option.
@item --exec-prefix=DIR
This option allows one to separate the architecture independent programs
from the configuration files and manual pages.
@item --with-cc=COMPILER
Use @code{COMPILER} as the C compiler.
@item --with-ccopts=FLAGS
Use @code{FLAGS} as the default set of C compiler flags.
Note that if you use the native Ultrix compiler on a
DECstation you are likely to lose if you pass no flags to cc; md4.c
takes an estimated 3,469 billion years to compile if you provide neither
the @samp{-g} flag nor the @samp{-O} flag to @samp{cc}.
@item --with-cppopts=CPPOPTS
Use @code{CPPOPTS} as the default set of C preprocessor flags. The most
common use of this option is to select certain @code{#define}'s for use
with the operating system's include files.
@item --with-linker=LINKER
Use @code{LINKER} as the default loader if it should be different from C
compiler as specified above.
@item --with-ldopts=LDOPTS
This option allows one to specify optional arguments to be passed to the
linker. This might be used to specify optional library paths.
@item --with-krb4
This option enables Kerberos V4 backwards compatibility using the
builtin Kerberos V4 library.
@item --with-krb4=KRB4DIR
This option enables Kerberos V4 backwards compatibility. The directory
specified by @code{KRB4DIR} specifies where the V4 header files should
be found (@file{/KRB4DIR/include}) as well as where the V4 Kerberos
library should be found (@file{/KRB4DIR/lib}).
@item --without-krb4
Disables Kerberos V4 backwards compatibility. This prevents Kerberos V4
clients from using the V5 services including the KDC. This would be
useful if you know you will never install or need to interact with V4
clients.
@item --with-netlib[=libs]
Allows for suppression of or replacement of network libraries. By
default, Kerberos V5 configuration will look for @code{-lnsl} and
@code{-lsocket}. If your operating system has a broken resolver library
(see @ref{Solaris versions 2.0 through 2.3}) or fails to pass the tests in
@file{src/tests/resolv} you will need to use this option.
@item --enable-shared
This option will turn on the building and use of shared library objects
in the Kerberos build. This option is only supported on certain
platforms.
@item --with-vague-errors
If enabled, gives vague and unhelpful error messages to the client... er,
attacker. (Needed to meet silly government regulations; most other
sites will want to keep this undefined.)
@item --with-kdc-kdb-update
Set this option if you want to allow the KDC to modify the Kerberos
database; this allows the last request information to be updated, as
well as the failure count information. Note that this doesn't work if
you're using slave servers!!! It also causes the database to be
modified (and thus needing to be locked) frequently. Please note that
the implementors do not regularly test this feature.
@item --with-kdb-db=database
The configuration process will try to determine a working set of
libraries required to implement the Kerberos database. Configure will
look for interfaces that use or emulate a @samp{ndbm} or @samp{dbm}
library. Failing that, a build in copy of the Berkeley DB code will be
used. You may decide to compile a different interface than the default
by specifying one of "ndbm", "dbm", or "db".
An important note on platforms where the @samp{ndbm} implementation is
based on @sc{GDBM} (such as the Linux Slackware distribution). @sc{GDBM}
has its own built in file locking which prevents simultaneous access to
the database from two separate processes in which one wants to modify
the database while the otherone only wants to read. (i.e. the KDC and
administrative servers). In this case, you will need to specify the use
of the Berkeley DB.
@end table
For example, in order to configure Kerberos on a Solaris machine using
the @samp{suncc} with the optimizer turned on, run the configure
script with the following options:
@example
% ./configure --with-cc=suncc --with-ccopts=-O
@end example
@node osconf.h, Shared Library Support, Options to Configure, Building Kerberos
@section @file{osconf.h}
There is one configuration file which you may wish to edit to control
various compile-time parameters in the Kerberos distribution:
@file{include/stock/osconf.h}. The list that follows is by no means
complete, just some of the more interesting variables.
Please note: The former configuration file @file{config.h} no longer
exists as its functionality has been merged into the auto-configuration
process. @xref{Options to Configure}.
@table @code
@item DEFAULT_PROFILE_PATH
The pathname to the file which contains the profiles for the known
realms, their KDCs, etc.
The profile file format is no longer the same format as Kerberos V4's
@file{krb.conf} file.
@item DEFAULT_LNAME_FILENAME
The pathname to the database that maps authentication names to local
account names. See kdb5_anadd(8).
@item DEFAULT_KEYTAB_NAME
The type and pathname to the default server keytab file (the equivalent
of Kerberos V4's @file{/etc/srvtab}).
@item DEFAULT_KDC_ENCTYPE
The default encryption type for the KDC.
@item KDCRCACHE
The name of the replay cache used by the KDC.
@item RCTMPDIR
The directory which stores replay caches.
@item DEFAULT_KDB_FILE
The location of the default database
@end table
@node Shared Library Support, OS Incompatibilities, osconf.h, Building Kerberos
@section Shared Library Support
Shared library support is provided for a few operating systems. There
are restrictions as to which compiler to use when using shared
libraries. In all cases, executables linked with the shared libraries in
this build process will have built in the location of the libraries,
therefore obliterating the need for special LD_LIBRARY_PATH, et al environment
variables when using the programs. Except where noted, multiple versions
of the libraries may be installed on the same system and continue to
work.
Currently the supported platforms are: NetBSD 1.0A, AIX 3.2.5, AIX 4.1,
Solaris 5.3, Alpha OSF/1 >= 2.1, HP-UX >= 9.X.
To enable shared libraries on the above platforms, run the configure
script with the option @samp{--enable-shared}.
One special note is that if the Kerberos V4 compatibility is compiled
in, you @b{must not} specify an alternate Kerberos V4 library from the
one in the tree or you will be missing references.
@menu
* Shared Library Theory::
* NetBSD Shared Library Support::
* AIX Shared Library Support::
* Solaris 5.3 Shared Library Support::
* Alpha OSF/1 Shared Library Support::
@end menu
@node Shared Library Theory, NetBSD Shared Library Support, Shared Library Support, Shared Library Support
@subsection Theory of How Shared Libraries are Used
An explanation of how shared libraries are implemented on a given
platform is too broad a topic for this manual. Instead this will touch
on some of the issues that the Kerberos V5 tree uses to support version
numbering and alternate install locations.
Normally when one builds a shared library and then links with it, the
name of the shared library is stored in the object
(i.e. libfoo.so). Most operating systems allows one to change name that
is referenced and we have done so, placing the version number into the
shared library (i.e. libfoo.so.0.1). At link time, one would reference
libfoo.so, but when one executes the program, the shared library loader
would then look for the shared library with the alternate name. Hence
multiple versions of shared libraries may be supported relatively
easily. @footnote{Under AIX for the RISC/6000, multiple versions of
shared libraries are supported by combining two or more versions of the
shared library into one file. The Kerberos build procedure produces
shared libraries with version numbers in the internal module names, so
that the shared libraries are compatible with this scheme.
Unfortunately, combining two shared libraries requires internal
knowledge of the AIX shared library system beyond the scope of this
document. Practicallyspeaking, only one version of AIX shared libraries
can be supported on a system, unless the multi-version library is
constructed by a programmer familiar with the AIX internals.}
All operating systems (that we have seen) provide a means for programs
to specify the location of shared libraries. On different operating
systems, this is either specified when creating the shared library, and
link time, or both.@footnote{Both are necessary sometimes as the shared
libraries are dependent on other shared libraries} The build process
will hardwire a path to the installed destination.
@node NetBSD Shared Library Support, AIX Shared Library Support, Shared Library Theory, Shared Library Support
@subsection NetBSD Shared Library Support
Shared library support has been tested under NetBSD 1.0A using
GCC 2.4.5. Due to the vagaries of the loader in the operating system,
the library load path needs to be specified in building libraries and in
linking with them. Unless the library is placed in a standard location
to search for libraries, this may make it difficult for developers to
work with the shared libraries.
@node AIX Shared Library Support, Solaris 5.3 Shared Library Support, NetBSD Shared Library Support, Shared Library Support
@subsection AIX Shared Library Support
AIX specifies shared library versions by combining multiple
versions into a single file. Because of the complexity of this process,
no automatic procedure for building multi-versioned shared libraries is
provided. Therefore, supporting multiple versions of the Kerberos shared
libraries under AIX will require significant work on the part of a
programmer famiiliar with AIX internals.
AIX allows a single library to be used both as a static library
and as a shared library. For this reason, the @samp{--enable-shared}
switch to configure builds only shared libraries. On other operating
systems, both shared and static libraries are built when this switch is
specified. As with all other operating systems, only non-shared static
libraries are built when @samp{--enable-shared} is not specified.
The AIX 3.2.5 linker dumps core trying to build a shared
@samp{libkrb5.a} produced with the GNU C compiler. The native AIX
compiler works fine. In addition, the AIX 4.1 linker is able to build a
shared @samp{libkrb5.a} when GNU C is used.
@node Solaris 5.3 Shared Library Support, Alpha OSF/1 Shared Library Support, AIX Shared Library Support, Shared Library Support
@subsection Solaris 5.3 Shared Library Support
Shared library support only works when using the Sunsoft C compiler. We
are currently using version 3.0.1.
The path to the shared library must be specified at link time as well as
when creating libraries.
@node Alpha OSF/1 Shared Library Support, , Solaris 5.3 Shared Library Support, Shared Library Support
@subsection Alpha OSF/1 Shared Library Support
Shared library support has been tested with V2.1 and higher of the
operating system. Shared libraries may be compiled both with GCC and the
native compiler.
One of the nice features on this platform is that the paths to the
shared libraries is specified in the library itself without requiring
that one specify the same at link time.
We are using the @samp{-rpath} option to @samp{ld} to place the library
load path into the executables. The one disadvantage of this is during
testing where we want to make sure that we are using the build tree
instead of a possibly installed library. The loader uses the contents of
@samp{-rpath} before LD_LIBRARY_PATH so we must specify a dummy _RLD_ROOT
and complete LD_LIBRARY_PATH in our tests.
The one disadvantage with the
method we are using
@node OS Incompatibilities, Using Autoconf, Shared Library Support, Building Kerberos
@section Operating System Incompatibilities
This section details operating system incompatibilities with Kerberos V5
which have been reported to the developers at MIT. If you find additional
incompatibilities, and/or discover work arounds to such problems, please
send a report to @b{krb5-bugs@@mit.edu}. Thanks!
@menu
* Ultrix 4.2/3::
* Alpha OSF/1 V1.3::
* Alpha OSF/1 V2.0++::
* BSDI::
* Solaris versions 2.0 through 2.3::
* Solaris 2.X::
* SGI Irix 5.X::
@end menu
@node Ultrix 4.2/3, Alpha OSF/1 V1.3, OS Incompatibilities, OS Incompatibilities
@subsection Ultrix 4.2/3
On the DEC MIPS platform, using the native compiler, @file{md4.c} and
@file{md5.c} can not be compiled with the optimizer set at level 1.
That is, you must specify either @samp{--with-ccopts=-O} and
@samp{--with-ccopts=-g} to configure. If you don't specify either, the
compile will never complete.
The optimizer isn't hung; it just takes an exponentially long time.
Compiling 6 out of the 48 algorithmic steps takes 3 seconds; compiling 7
steps takes 9 seconds; compiling 8 steps takes 27 seconds, and so on.
Calculations estimate it will finish in approximately 3,469 billion
years....
Using GCC instead of the native compiler will also work fine, both with
or without optimization.
@node Alpha OSF/1 V1.3, Alpha OSF/1 V2.0++, Ultrix 4.2/3, OS Incompatibilities
@subsection Alpha OSF/1 V1.3
Using the native compiler, compiling with the @samp{-O} compiler flag
causes the @code{asn.1} library to be compiled incorrectly.
Using GCC version 2.6.3 or later instead of the native compiler will also work
fine, both with or without optimization.
@node Alpha OSF/1 V2.0++, BSDI, Alpha OSF/1 V1.3, OS Incompatibilities
@subsection Alpha OSF/1 V2.0++
There used to be a bug when using the native compiler in compiling
@file{md4.c} when compiled without either the @samp{-O} or @samp{-g}
compiler options. We have changed the code and there is no problem
under V2.1, but we do not have access to V2.0 to test and see if the
problem would exist there. (We welcome feedback on this issue). There
was never a problem in using GCC version 2.6.3.
In version 3.2 and beyond of the operating system, we have not seen any
problems with the native compiler.
@node BSDI, Solaris versions 2.0 through 2.3, Alpha OSF/1 V2.0++, OS Incompatibilities
@subsection BSDI
BSDI versions 1.0 and 1.1 reportedly has a bad @samp{sed} which causes
it to go into an infinite loop during the build. The work around is
to use a @samp{sed} from somewhere else, such as GNU. (This may be
true for some versions of other systems derived from BSD 4.4, such as
NetBSD and FreeBSD.)
@node Solaris versions 2.0 through 2.3, Solaris 2.X, BSDI, OS Incompatibilities
@subsection Solaris versions 2.0 through 2.3
The @code{gethostbyname()} routine is broken; it does not return a fully
qualified domain name, even if you are using the Domain Name Service
routines. Since Kerberos V5 uses the fully qualified domain name as the
second component of a service principal (i.e,
@samp{host/tsx-11.mit.edu@@ATHENA.MIT.EDU}), this causes problems for servers
who try to figure out their own fully qualified domain name.
Workarounds:
@enumerate
@item
Supply your own resolver library. (such as bind-4.9.3pl1 availavle
from ftp.vix.com)
@item
Upgrade to Solaris 2.4
@item
Make sure your /etc/nsswitch.conf has `files' before `dns' like:
@example
hosts: files dns
@end example
and then in /etc/hosts, make sure there is a line with your
workstation's IP address and hostname, with the fully qualified domain
name first. Example:
@example
18.172.1.4 dcl.mit.edu dcl
@end example
Note that making this change may cause other programs in your
environment to break or behave differently.
@end enumerate
@node Solaris 2.X, SGI Irix 5.X, Solaris versions 2.0 through 2.3, OS Incompatibilities
@subsection Solaris 2.X
You @b{must} compile Kerberos V5 without the UCB compatibility
libraries. This means that @file{/usr/ucblib} must not be in the
LD_LIBRARY_PATH environment variable when you compile it. Alternatively
you can use the @code{-i} option to @samp{cc}, by using the specifying
@code{--with-ccopts=-i} option to @samp{configure}.
@node SGI Irix 5.X, , Solaris 2.X, OS Incompatibilities
@subsection SGI Irix 5.X
If you are building in a tree separate from the source tree, the vendors
version of make does not work properly with regards to
@samp{VPATH}. It also has problems with standard inference rules in 5.2
(not tested yet in 5.3) so one needs to use GNU's make.
Under 5.2, there is a bug in the optional System V @code{-lsocket}
library in which the routine @code{gethostbyname()} is broken. The
system supplied version in @code{-lc} appears to work though so one may
simply specify @code{--with-netlib} option to @samp{configure}.
In 5.3, @code{gethostbyname()} is no longer present in @code{-lsocket} and
is no longer an issue.
@node Using Autoconf, , OS Incompatibilities, Building Kerberos
@section Using @samp{Autoconf}
(If you are not a developer, you can skip this section.)
In most of the Kerberos V5 source directories, there is a
@file{configure} script which automatically determines the compilation
environment and creates the proper Makefiles for a particular platform.
These @file{configure} files are generated using @samp{autoconf} version
2.4, which can be found in the @file{src/util/autoconf} directory in the
distribution.
Normal users will not need to worry about running @samp{autoconf}; the
distribution comes with the @file{configure} files already prebuilt.
Developers who wish to modify the @file{configure.in} files should see
@ref{Top, , Overview, autoconf, The Autoconf Manual}.
Note that in order to run @samp{autoconf}, you must have GNU @samp{m4}
in your path. Before you use the @samp{autoconf} in the Kerberos V5
source tree, you may also need to run @samp{configure}, and then run
@samp{make} in the @file{src/util/autoconf} directory in order to
properly set up @samp{autoconf}.
One tool which is provided for the convenience of developers can be
found in @file{src/util/reconf}. This program should be run while the
current directory is the top source directory. It will automatically
rebuild any @file{configure} files which need rebuilding. If you know
that you have made a change that will require that all the
@file{configure} files need to be rebuilt from scratch, specify the
@code{--force} option:
@example
% cd /u1/krb5/src
% ./util/reconf --force
@end example
The developmental sources are a raw source tree (before it's been packaged
for public release), without the pre-built @file{configure} files.
In order to build from such a source tree, you must do:
@example
% cd krb5/util/autoconf
% ./configure
% make
% cd ../..
% util/reconf
@end example
Then follow the instructions for building packaged source trees (above).
To install the binaries into a binary tree, do:
@example
% cd /u1/krb5/src
% make all
% make install DESTDIR=somewhere-else
@end example
@node Installation, Troubleshooting, Building Kerberos, Top
@chapter Installation
When you are installing Kerberos for the first time at a site, you must
first decide on the realm name you will use for your site, and select a
machine to host the @dfn{Kerberos server}, which is also known as the
@dfn{KDC} (@dfn{Key Distribution Center}). The KDC must be located on a
secure machine, since its database contains the keys for the entire
realm. It is extremely important that the database be kept secure, if
the realm's Kerberos service is to remain secure.
Once a KDC is installed and configured, you may then set up one or more
client machines, and one or more application machines.
@menu
* Background::
* Installation on any Machine::
* Installing the KDC::
* Migrating from V4 to V5 Kerberos::
* A Sample Application::
* Installing Kerberos Applications::
* Common Kerberos Service Names::
@end menu
@node Background, Installation on any Machine, Installation, Installation
@section Background Information
Your system's security is only as good as the security of your
@samp{root} password. You should take other precautions to protect your
system security in addition to installing Kerberos. Kerberos cannot
protect you from someone who is able to steal @samp{root} privileges.
Kerberos also does not protect you from break-ins caused by bugs in your
daemons (e.g., @samp{fingerd} or @samp{sendmail}). On almost all UNIX
systems, if intruders can break in as an ordinary users, they can obtain
superuser privileges by exploiting bugs or imperfect configuration files.
@node Installation on any Machine, Installing the KDC, Background, Installation
@section Installation on any Machine
The following steps must be performed no matter what type of
machine (KDC, Client, or Application server) you are installing. All
machines functioning within the same administrative domain must use the
same Kerberos realm name; and all machines which are using Kerberos must
have the Kerberos configuration files properly installed.
If you are installing Kerberos on a machine that will act only as a
Kerberos client, this section describes all that you need to do. If you
are installing a KDC, or an Kerberos Application server, you will also
need to complete the procedures detailed in @ref{Installing the KDC}, or
@ref{A Sample Application}, after you finish with the procedures found
in this section.
@menu
* Picking a Realm Name::
* Configuration files::
* Recommended Programs::
@end menu
@node Picking a Realm Name, Configuration files, Installation on any Machine, Installation on any Machine
@subsection Picking a Realm Name
Before you install Kerberos V5 at your site, you have to choose a
@dfn{realm name}, the name that specifies the system's administrative
domain. By convention, we suggest that you use your internet domain
name, in capital letters. (Kerberos realm names are case-sensitive, so
it's important that your realm name be in all upper case.) For example,
if your internet domain is @code{cygnus.com} (so that you have hostnames
such as @code{ftp.cygnus.com} and @code{tweedledum.cygnus.com}), then
your Kerberos realm should be @code{CYGNUS.COM}. Please note that
changing realm names is hard. Get it right the first time.
@node Configuration files, Recommended Programs, Picking a Realm Name, Installation on any Machine
@comment node-name, next, previous, up@section
@subsection Configuration files
@menu
* krb5.conf::
* Converting V4 configuration files::
* /etc/services::
@end menu
@node krb5.conf, Converting V4 configuration files, Configuration files, Configuration files
@subsubsection The @file{krb5.conf} File
The @file{krb5.conf} file contains information needed by the Kerberos V5
library including a system's default Kerberos
realm, and the locations of the Kerberos servers.
The @file{krb5.conf} uses an INI-style format. Sections are delimited by
square braces; within each section, there are relations where tags can
be assigned to have specific values. Tags can also contain a
subsection, which contains further relations or subsections. A tag can
be assigned to multiple values.
Create a @file{/etc/krb5.conf} file using the following format:
@example
[libdefaults]
default_realm = <realm_name>
[realms]
<realm_name> = @{
kdc = <master_server_name>
admin_server = <master_server_name>
default_domain = <domain_name>
@}
[domain_realm]
<.domain.name> = <realm_name>
@end example
Where @samp{realm_name} specifies the default realm to be used by that
particular system, and @samp{master_server_name} specifies the machine
name on which you will run the master server. The keywords @samp{kdc}
and @samp{admin_server} lists the location of the realms KDC and
administration servers.
For example, if your realm name is @samp{ATHENA.MIT.EDU} and your master
server's name is @samp{kerberos.mit.edu}, the file should have these
contents:
@example
[libdefaults]
default_realm = ATHENA.MIT.EDU
[realms]
ATHENA.MIT.EDU = @{
kdc = KERBEROS.MIT.EDU
admin_server = KERBEROS.MIT.EDU
default_domain = MIT.EDU
@}
[domain_realm]
.mit.edu = ATHENA.MIT.EDU
mit.edu = ATHENA.MIT.EDU
@end example
In many situations, the default realm in which a host operates will be
identical to its Internet domain name, with the first component removed
and all letters capitalized. For example, @code{ftp.cygnus.com} is
traditionally in the realm @code{CYGNUS.COM}.
If this is not the case, you will need to establish a translation from
host name or domain name to realm name. This is accomplished with the
@samp{[domain_realm]} stanza.
Each line of the translation file specifies either a host name or domain
name, and its associated realm:
@example
[domain_realm]
<.domain.name> = KERBEROS.REALM1
<host.name> = KERBEROS.REALM2
@end example
For example, to map all hosts in the domain LSC.MIT.EDU to LSC.MIT.EDU
but the host FILMS.LSC.MIT.EDU to MIT.EDU your file would read:
@example
[domain_realm]
.LSC.MIT.EDU = LSC.MIT.EDU
FILMS.LSC.MIT.EDU = MIT.EDU
@end example
If a particular host name matches both a domain name and a host name in
@samp{[domain_realm]}, the entry containing the host name takes precedence.
See the @file{[SOURCE_DIR]/config-files/krb5.conf} file for an example
@file{krb5.conf} file. That file has examples of how to provide backup
servers for a given realm (additional lines with the same leading realm
name) and how to designate servers for remote realms.
@node Converting V4 configuration files, /etc/services, krb5.conf, Configuration files
@subsubsection Conversion of V4 configuration files
Kerberos V4's @file{krb.conf} and @file{krb.realms} files formats are no
longer used by the V5 library. A @sc{PERL} script has been provided to allow
for "easy" generation of an initial @file{krb5.conf}. It is located in
@file{[SOURCE_DIR]/config-files/convert-config-files}. The produced file
should be checked for errors.
Note that if you are planning on using certain applications with
Kerberos V4 compatibility compiled in, the V4 library still needs the
files @file{krb.conf} and @file{krb.realms}.
@node /etc/services, , Converting V4 configuration files, Configuration files
@subsubsection /etc/services
All hosts which will use Kerberos will need to have certain ports
defined in the system's @file{/etc/services} file. The file
@file{[SOURCEDIR]/config-files/services.append} contains the entries
which should be appended to the @file{/etc/services} file. Please note
that not all of the entries are required as several of the programs have
defaults built into the programs. This will be documented sometime in
the future.
If you are using the Network Information Services (NIS) or Yellow
Pages (YP), you will need to add the services in the
@file{services.append} file to the services exported in the NIS or YP
server.
@node Recommended Programs, , Configuration files, Installation on any Machine
@subsection Recommended Programs
The following files should be installed on all machines which are
running Kerberos, either as a client, a KDC, or an application server:
If you used the default @samp{make install} without using the
@samp{--prefix} argument to @file{configure}, then [K_USER] refers to
@file{/usr/local/bin}.
@itemize @bullet
@item @file{/etc/krb5.conf} --- This files contains information required
by Kerberos V5 giving system defaults as well as locations of Kerberos
servers.
@item @file{[K_USER]/kinit} --- This program allows you to obtain
Kerberos credentials.
@item @file{[K_USER]/kdestroy} --- This program allows you to destroy
Kerberos credentials which are no longer needed.
@item @file{[K_USER]/klist} ---- This program allows you to list the
credentials found in your credentials cache.
@end itemize
@node Installing the KDC, Migrating from V4 to V5 Kerberos, Installation on any Machine, Installation
@section Installing the KDC
@menu
* kdc.conf::
* Initializing the KDB::
* Storing the Master Password::
* Adding Users to the Database::
* Starting the Kerberos Server::
* Setting up Slave Kerberos Servers::
* Inter-realm Kerberos Operation::
* The Administration Server::
* Testing the Kerberos Server::
@end menu
@node kdc.conf, Initializing the KDB, Installing the KDC, Installing the KDC
@subsection The optional @file{kdc.conf} profile
There is an optional configuration file @file{kdc.conf} that allows one
to specify per-realm configuration data to be used by the Kerberos V5
Authentication Service and Key Distribution Center. This information
includes database locations, key and per-realm defaults, port numbers,
ticket life times, etc. The location of the configuration file is
@file{/usr/local/lib/krb5kdc/kdc.conf}.
See the man page or @file{[SOURCEDIR]/config-files/kdc.conf.M} for more
details.
This document assumes that you do not have the @file{kdc.conf}
configuration file installed.
Note also that @code{[logging]} subsection to @file{/etc/krb5.conf} can
be used to specify where to syslog messages regarding server activity.
@node Initializing the KDB, Storing the Master Password, kdc.conf, Installing the KDC
@subsection Initializing the Kerberos Database
Login to the Kerberos KDC, and use the @samp{su} command to become root.
If you installed the Kerberos administration tools
with the @samp{make install} command and the default pathnames,
they should be in the @file{/usr/local/admin} directory.
If you installed the tools in a different directory,
hopefully you know what it is.
From now on, we will refer to this directory as [ADMIN_DIR].
The default database will be located in the directory
@file{/usr/local/lib/krb5kdc} unless changed in the configuration
process. From now on, we will call this [DB_DIR].
The @samp{kdb5_create} command creates and initializes the master database.
It asks you to the database's master password.
Do not forget this password.
If you do, the database becomes useless.
(Your realm name should be substituted for [REALMNAME] below.)
@xref{Storing the Master Password} for an alternative way of dealing
with this master password.
Because the install process does not create [DB_DIR] you need to do so
yourself.
Use @samp{kdb5_create} as follows:
@example
# @b{mkdir [DB_DIR]}
# @b{[ADMIN_DIR]/kdb5_create}
Initializing database '[DB_DIR]/principal' for realm '[REALMNAME]',
master key name 'K/M@@[REALMNAME]'
You will be prompted for the database Master Password.
It is important that you NOT FORGET this password.
Enter KDC database master key: @b{<-- [Enter the master password.]}
Re-enter KDC database master key to verify: @b{<-- [Re-enter it.]}
@end example
@node Storing the Master Password, Adding Users to the Database, Initializing the KDB, Installing the KDC
@subsection Storing the Master Password
The @samp{kdb5_stash} command "stashes" the master password in the file
@file{[DB_DIR]/.k5.[REALM.NAME]} so that the Kerberos server can be started
automatically during an unattended reboot of the master server. Other
administrative programs use this hidden password so that they can access
the master database without someone having to manually provide the
master password. This command is an optional one; if you'd rather enter
the master password each time you start the Kerberos server, don't use
@samp{kdb5_stash}.
On the one hand, if you use @samp{kdb5_stash}, a copy of the master key
will reside on a disk, which may not be acceptable; on the other hand,
if you don't use @samp{kdb5_stash}, the server cannot be started unless
someone is around to type the password manually.
The command merely prompts for the master password:
@example
# @b{[ADMIN_DIR]/kdb5_stash}
Enter KDC database master key: @b{<-- [Enter the master password.]}
@end example
WARNING: If your Kerberos database master key is compromised and the
database is obtained, the security of your entire authentication system
is compromised. (If this happens to you, all of your user's passwords must
be set to new values manually --- i.e., not using Kerberos.) The master
key must be a carefully kept secret. If you keep backups, you must
guard all the master keys you use, in case someone has stolen an old
backup and wants to attack users' whose passwords haven't changed since
the backup was stolen. This is why we provide the option not to store
it on disk.
@node Adding Users to the Database, Starting the Kerberos Server, Storing the Master Password, Installing the KDC
@subsection Adding Users to the Database
The @samp{kdb5_edit} program may be used to add new users and services to
the master database, and to modify existing database
information. @xref{The Administration Server} for an alternative method
once the Kerberos environment is up and running.
For example, to add yourself to the newly created database: (replace
@samp{[USERNAME]} with your username with.
@example
# @b{[ADMIN_DIR]/kdb5_edit}
kdb5_edit: @b{ank [USERNAME]}
Enter password: @b{<-- [Enter your password.]}
Re-enter password for verification: @b{<-- [Re-enter it.]}
kdb5_edit: @b{quit}
@end example
The @samp{ank} command is short for "add_new_key"; this command adds a
new user to the database. To see what other commands which @samp{kdb5_edit}
supports, type @kbd{? @key{RET}} at the @samp{kdb5_edit} prompt.
@node Starting the Kerberos Server, Setting up Slave Kerberos Servers, Adding Users to the Database, Installing the KDC
@subsection Starting the Kerberos Server
Assuming that you didn't use the @samp{--prefix} argument to
@file{configure}, then [K_SERVER] refers to @file{/usr/local/sbin}.
In order to start the Kerberos server, simply run it. It will fork and
disassociate from the terminal unless the @samp{-n} argument is used.
@example
# @b{[K_SERVER]/krb5kdc}
@end example
If you have used the @samp{kdb5_stash} command to store the master database password,
the server will start automatically.
If you did not use @samp{kdb5_stash},
use the following command:
@example
# @b{[K_SERVER]/krb5kdc -m}
@end example
The server will prompt you to enter the master password before actually
starting itself.
@node Setting up Slave Kerberos Servers, Inter-realm Kerberos Operation, Starting the Kerberos Server, Installing the KDC
@subsection Setting up Slave Kerberos Servers
Slave Kerberos servers allow clients to be able to get Kerberos tickets
even when the Master server is not available. Users will not be able to
change their passwords --- changes can only be made to database on the
Master server; however, users will be able to authenticate to
application servers, which is critically important in a distributed
client-server environment. The current implementation of the client code
does not provide load sharing in that the order of servers contacted is
the same as those listed in the @file{krb5.conf} file.
@menu
* Kerberos Slave Database Propagation::
* Installing a Slave Server::
@end menu
@node Kerberos Slave Database Propagation, Installing a Slave Server, Setting up Slave Kerberos Servers, Setting up Slave Kerberos Servers
@subsubsection Kerberos Slave Database Propagation
In order to propagate the Kerberos database from the Master server to
the slaves, the @samp{kprop} and @samp{kpropd} client/server programs
are used. Periodically, the Master server will dump the Kerberos
database out into an ASCII format, using the @samp{kdb5_edit} program.
The master server will then run @samp{kprop} to propagate the dumped
database file to each slave server.
On the slave server, the @samp{kpropd} program is invoked out of
@samp{inetd} server. After @samp{kprop} and @samp{kpropd} have
mutually authenticated with one another, and @samp{kpropd} is satisfied
with the identity of the Master server, then the dumped ASCII database
is transferred to the slave server in an encrypted fashion. After the
database is transfered, @samp{kpropd} will then run @samp{kdb5_edit}
with the appropriate arguments in order to undump the database into a
usable form by the KDC on the slave server.
@node Installing a Slave Server, , Kerberos Slave Database Propagation, Setting up Slave Kerberos Servers
@subsubsection Installing a Slave Server
@b{To be written.}
@node Inter-realm Kerberos Operation, The Administration Server, Setting up Slave Kerberos Servers, Installing the KDC
@subsection Inter-realm Kerberos Operation
@b{To be written.}
@node The Administration Server, Testing the Kerberos Server, Inter-realm Kerberos Operation, Installing the KDC
@subsection The Administration Server
There is currently an administration server in the Kerberos source tree.
It is, however, very rough, and it will likely be significantly changed
or replaced before the 1.0 release. Hence, this manual does not
document the current administration server. Changes to the database can
be made by logging in to the KDC directly, and using the
@samp{kdb5_edit} program; see @ref{Adding Users to the Database}.
@node Testing the Kerberos Server, , The Administration Server, Installing the KDC
@subsection Testing the Kerberos Server
Use the @samp{kinit} command to obtain Kerberos credentials. This command
creates your credentials cache and stores your credentials in it.
If you used the default @samp{make install} command and directories to
install the Kerberos user utilities, @samp{kinit} will be in the
@file{/usr/local/bin} directory. From now on, we'll refer to the Kerberos user
commands directory as [K_USER].
Use @samp{kinit} as follows:
@example
% @b{[K_USER]/kinit [USERNAME]}
Password for [USERNAME]@@[REALMNAME]: @b{<-- enter your password}
@end example
Use the @samp{klist} program to list the contents of your ticket file.
@example
% @b{[K_USER]/klist}
Ticket cache: /tmp/krb5cc_15806
Default principal: [USERNAME]@@[REALMNAME]
Valid starting Expires Service principal
31-Jan-95 21:58:32 1-Feb-95 05:57:39 krbtgt/[REALMMNAME]@@[REALMNAME]
@end example
@ignore
@c not yet...
If you have any problems, you can examine the log file
@file{/krb5/kerberos.log} on the Kerberos server machine to see if
there was some sort of error.
@end ignore
@node Migrating from V4 to V5 Kerberos, A Sample Application, Installing the KDC, Installation
@section Migrating from V4 to V5 Kerberos
@b{To be written.} A rough idea of the procedure that one may follow is
in @file{[SOURCE_DIR]/kdc/migration.doc}.
@node A Sample Application, Installing Kerberos Applications, Migrating from V4 to V5 Kerberos, Installation
@section A Sample Application
This release of Kerberos comes with a sample application server and a
corresponding client program. You will find this software
@file{[K_SERVER]/sserver} and @file{[K_USER]/sclient}, which is the
server's executable, and the client program's executable, respectively.
The programs are rudimentary.
When they have been installed (the installation procedure is described
in detail later), they work as follows:
@enumerate
@item
The user starts @samp{sclient} and provides as arguments
to the command the name of the server machine and an optional port on
which to contact the server.
@item
@samp{sclient} contacts the server machine and
authenticates the user to @samp{sserver}.
@item
@samp{sserver} authenticates itself to @samp{sclient} (thus
performing mutual authentication), and
then returns a message to the client program.
This message contains the name of the Kerberos principal that was used
to authenticate to @samp{sserver}.
@item
@samp{sclient} displays the server's message on the user's
terminal screen.
@end enumerate
@menu
* Installing the Sample Application::
* Testing the Sample Server::
@end menu
@node Installing the Sample Application, Testing the Sample Server, A Sample Application, A Sample Application
@subsection Installing the Sample Application
In general,
you use the following procedure to install a Kerberos-authenticated
server-client system.
@enumerate
@item
Add the appropriate entry to the Kerberos database using @samp{kdb_edit}
@item
Create a @file{/etc/v5srvtab} file for the server machine.
@item
Install the service program and the @file{/etc/v5srvtab}
file on the server machine.
@item
Install the client program on the client machine.
@item
Update the @file{/etc/services} file on the client and server machines.
@end enumerate
We will use the sample application as an example, although programs
which do not take requests via the @samp{inetd} program may have
slightly different installation procedures. @samp{Inetd} starts
@samp{sserver} each time a client process contacts the server machine.
@samp{sserver} processes the request, terminates, then is restarted
when @samp{inetd} receives another @samp{sserver} request. When you
install the program on the server, you must add a @samp{sample} entry to
the server machine's @file{/etc/inetd.conf} file.
The following description assumes that you are installing
@samp{sserver} on the machine @samp{jimi.mit.edu}.
Here's the process, step by step:
@enumerate
@item
Login as root or @samp{su} to root on the Kerberos server machine.
Use the @samp{kdb5_edit} program to create an entry for
@code{sample} in the Kerberos database:
@example
# @b{[ADMIN_DIR]/kdb5_edit}
kdb5_edit: @b{add_random_key sample/jimi.mit.edu}
kdb5_edit: @b{quit}
@end example
(Note: @samp{add_random_key} may be abbreviated as @samp{ark}.)
@item
Use @samp{kdb5_edit} to create a @file{srvtab} file
for @samp{sserver}'s host machine:
@example
# @b{[ADMIN_DIR]/kdb5_edit}
kdb5_edit: @b{extract_srvtab jimi.mit.edu sample}
'sample/jimi.mit.edu@@ATHENA.MIT.EDU' added to keytab 'WRFILE:jimi.mit.edu-new-srvtab'
kdb5_edit: @b{quit}
@end example
(Note: @samp{extract_srvtab} may be abbreviated as @samp{xst}.)
Transfer the @file{jimi.mit.edu-new-srvtab} file to @samp{jimi.mit.edu}
and install it as @file{/etc/v5srvtab}.
@b{WARNING}: Note that this file is equivalent to the service's password and
should be treated with care. For example, it could be transferred by
removable media, but should not be sent over an open network in the
clear. This file should installed such that only the root user can read
it.
@item
Add the following line to the @file{/etc/services} file on
@samp{jimi.mit.edu}, and on all machines that will run the
@samp{sample_client} program:
@example
sample 906/tcp # Kerberos sample app server
@end example
@item
Add a line similar to the following line to the @file{/etc/inetd.conf}
file on @samp{sample_server}'s machine:
@example
sample stream tcp nowait switched root
[K_SERVER]/sserver sample_server
@end example
where [K_SERVER] should be substituted with
the path to the @samp{sserver} program.
(This @file{inetd.conf} information should be placed on one line.)
You should examine existing lines in @file{/etc/inetd.conf} and use the
same format used by other entries (e.g. for telnet). Most systems do
not have a column for the `switched' keyword, and some do not have a
column for the username (usually `root', as above).
@item
Restart @samp{inetd} by sending the current @samp{inetd} process
a hangup signal:
@example
# @b{kill -HUP} @i{process_id_number}
@end example
@item
The @samp{sserver} is now ready to take @samp{sclient} requests.
@end enumerate
@node Testing the Sample Server, , Installing the Sample Application, A Sample Application
@subsection Testing the Sample Server
Assume that you have installed @samp{sserver} on @samp{jimi.mit.edu}.
Login to your workstation and use the @samp{kinit} command to
obtain a Kerberos ticket-granting ticket:
@example
% @b{[K_USER]/kinit [USERNAME]}
Password for [USERNAME]@@[REALMNAME]: @b{<--- Enter your password}
@end example
Now use the @samp{sclient} program as follows:
@example
% @b{[K_USER]/sclient jimi}
@end example
The command should display something like the following:
@example
sendauth succeeded, reply is:
reply len 29, contents:
You are [USERNAME]@@[REALMNAME]
@end example
@node Installing Kerberos Applications, Common Kerberos Service Names, A Sample Application, Installation
@section Installing Kerberos Applications
In addition to the sample application, Kerberos comes with
several servers that can be installed on workstations to provide secure
network services such as FTP, Telnet, and Rlogin. This section
describes these services and how to install them. First, a general
procedure is outlined for configuring a workstation to run Kerberos
application servers. Then, details of the particular configuration
options required by each server are presented.
@menu
* Levels of Security::
* Preparing a Workstation for Kerberos Application Servers::
* BSD Utilities::
* Telnet and FTP::
@end menu
@node Levels of Security, Preparing a Workstation for Kerberos Application Servers, Installing Kerberos Applications, Installing Kerberos Applications
@subsection Levels of Security
Before installing Kerberized servers, it is a good idea to
decide on a security policy for your environment. While developing a
comprehensive security policy is beyond the scope of these instructions,
there are several interactions between Kerberos servers and non-Kerberos
servers, as well as different modes in which Kerberos servers can run
that should be considered. In general, there are three levels of
connections:
@enumerate
@item
Encrypted Kerberos connections are the most secure services provided by
the Kerberos environment. Only encrypted services provide
confidentiality---encryption is required to make sure a passive
eavesdropper does not collect sensitive data, such as passwords, sent
over connections. Besides providing confidentiality, encryption
provides protection against active attacks. Without encryption or some
other form of integrity, an attacker may be able to insert commands or
change data in an authenticated session.
@item
The next level of security is Kerberos-authenticated services without
encryption. Without encryption, there is no confidentiality, and some
active attacks are possible. However, unencrypted services are faster
and are available commercially outside the United States. In addition,
the window of exposure to attack is generally limited to the lifetime of
a session---it is difficult for an attacker who does not have tickets to
start a new session if a Kerberos authentication exchange must take
place at the beginning of every session.
@item
Passworded services provide the next lower level of security.
Unfortunately, it is all-to-easy for a passive attacker to use software
such as a packet sniffer to find passwords traveling over a network.
Additionally, once an attacker knows a password, they can start
additional sessions at future times until the password is changed from a
secure location. Despite the disadvantages of password-based network
services, there are some common reasons for enabling them. First, most
clients only support password-based services; not everyone has Kerberos
or other cryptographically-secure network services. Second, in some
environments, where the network is secure, passwords may be a reasonable
solution. Also, particularly on public-access systems, it is common to
enable password-based services for normal users, while using more-secure
services such as Kerberos for root logins by administrators.
@item
The least secure common category of services are trust or host-based
services. These services use an IP address or client-supplied assertion
to provide authentication. Examples of host-based services include
@samp{rlogin}, @samp{rsh}, and the @samp{on} or @samp{rexd} service. It
is generally sufficient to know that a user exists on a target system,
and to know that a host-based or trust-based service is enabled in order
to exploit the service. Whenever possible, these services should be
disabled; there are few situations in which an a security policy is both
compatible with Kerberos and host-based services.
@end enumerate
Next, decide whether Kerberos V4 compatibility is necessary.
Unencrypted Kerberos V4 services suffer from all the problems of
unencrypted Kerberos V5 services: lack of confidentiality and
susceptibility to active attack. In addition, the lack of a replay cache
in Kerberos V4 makes these active attacks much easier. Also, design bugs
in the Kerberos V4 BSD utilities such as @samp{rlogin}, @samp{rsh} and
@samp{rcp} cause the availability of an unencrypted service to
significantly decrease the security of a system, even if only the
encrypted service is ever used. For example, a system that runs both
encrypted and unencrypted Kerberos V4 @samp{rlogin} servers is less secure
than a system only running the encrypted service, even if users only
ever connect to the encrypted service.
Therefore, if Kerberos V4 interoperability is desired or required,
try to avoid running unencrypted Kerberos V4 services wherever possible.
In particular, only enable encrypted @samp{rlogin} if at all possible.
Naturally, some environments will require additional Kerberos V4
functionality, like @samp{rsh}. The Kerberos V5 versions of these services,
with Kerberos V4 interoperability enabled, are not any weaker than their
Kerberos V4 counterparts. So, if the existing Kerberos V4 security policy
allows these services, then enabling them under the Kerberos V5 security
policy should not be a problem.
In addition, the issue of compatibility with older Kerberos V5
clients must be considered. For the most part, this compatibility is
automatic, and has few security implications. The major exception to
this is the BSD utilities. Until Kerberos V5 Beta6, these utilities
inherited a few design defects from the Kerberos V4 BSD utilities. In
particular, the presence of an unencrypted service that was never used
adversely effected the security of an encrypted service. The solution
that was adopted preserves compatibility with Kerberos V5 Beta5 clients.
Unfortunately, older clients are incompatible with this scheme. If
interoperability with older clients is necessary, then the new scheme
for checksums can be disabled on the server. If these checksums are
disabled, there is a short window between when a connection is opened
and when the replay cache is updated where an active attack is possible.
Alternatively, sites wishing to enable all security features may wish to
disable compatibility with Kerberos V5 Beta5 BSD utilities.
@xref{Checksums}, for full details.
In conclusion, as you prepare to install Kerberos application
servers, you should have answers to the following questions:
@enumerate
@item
What levels of services are appropriate for your security policy:
encrypted services, authenticated but not encrypted services,
password-based services, or host-based services?
@item
Do you wish to enable Kerberos V4 compatibility? If so, do you need to
enable unencrypted services?
@item
Do you need compatibility with Kerberos V5 clients before Beta5
(released in May, 1995)? Do you wish to disable compatibility with
Beta5 clients for slightly enhanced security?
@end enumerate
@node Preparing a Workstation for Kerberos Application Servers, BSD Utilities, Levels of Security, Installing Kerberos Applications
@subsection Preparing a Workstation for Kerberos Application Servers
The following procedure is very similar to the installation
procedure for the sample Kerberos server. @xref{Installing
the Sample Application}. However, instead of using the sample service,
this configuration is designed to set up host-based services.
The following description assumes that you are installing @samp{sserver}
on the machine @samp{jimi.mit.edu}. Repeat these steps for each
workstation that will be running host-based servers. Note that it is
not necessary to run these procedures on client machines--machines used
only to connect to secure network services, but that do not run any
servers of their own. Here's the process, step by step:
@enumerate
@item
Login as root or @samp{su} to root on the Kerberos server machine.
Use the @samp{kdb5_edit} program to create a service entry for
@code{host} in the Kerberos database:
@example
# @b{[ADMIN_DIR]/kdb5_edit}
kdb5_edit: @b{add_random_key host/jimi.mit.edu}
kdb5_edit: @b{quit}
@end example
(Note: @samp{add_random_key} may be abbreviated as @samp{ark}.)
@item
Use @samp{kdb5_edit} to create a @file{srvtab} file
for @samp{sserver}'s host machine:
@example
# @b{[ADMIN_DIR]/kdb5_edit}
kdb5_edit: @b{extract_srvtab jimi.mit.edu host}
'host/jimi.mit.edu@@ATHENA.MIT.EDU' added to keytab 'WRFILE:jimi.mit.edu-new-srvtab'
kdb5_edit: @b{quit}
@end example
(Note: @samp{extract_srvtab} may be abbreviated as @samp{xst}. Also,
additional services can be listed after @samp{host} on the
@samp{extract_srvtab} line; for example if the host jimi also runs the
sample server, the @samp{sample} service might have been listed after
host.)
Transfer the @file{jimi.mit.edu-new-srvtab} file to @samp{jimi.mit.edu}
and install it as @file{/etc/v5srvtab}.
@b{WARNING}: Note that this file is equivalent to the service's password and
should be treated with care. For example, it could be transferred by
removable media, but should not be sent over an open network in the
clear. This file should be installed such that only the root user can read
it.
@item
Make sure that the @samp{/etc/services} file has been updated to include
Kerberos services. In particular, look for @samp{klogin},
@samp{eklogin}, and @samp{kshell}.
@item
For each server you plan to run, add a line to @file{/etc/inetd.conf}.
The following sections will give details on what this line should look
like for each Kerberos application service.
@item
Consider removing non-Kerberized services like @samp{rlogin},
@samp{rsh}, @samp{rexd}, and others, in accordance with the security policy you decided on in the last section.
@item
Restart @samp{inetd}. On most systems, this is done by sending the current @samp{inetd} process
a hangup signal:
@example
# @b{kill -HUP} @i{process_id_number}
@end example
@item
Try using the Kerberos applications to connect to the host.
@end enumerate
@node BSD Utilities, Telnet and FTP, Preparing a Workstation for Kerberos Application Servers, Installing Kerberos Applications
@subsection BSD Utilities
This section describes installing servers for the BSD utilities:
@samp{kshd} and @samp{klogind}. The @samp{klogind} server implements the
protocol used by the Kerberized @samp{rlogin} client. The @samp{kshd}
server implements the protocol used by the @samp{rsh} and @samp{rcp}
clients.
These daemons take a common set of options to enable support for
different versions of Kerberos. The @samp{-5} option enables Kerberos
V5 support, and the @samp{-4} option enables Kerberos V4 support. At
least one of these options must be supplied or the server will refuse
all connections. Both options can be supplied if compatibility with
both versions of Kerberos is desired.
Both the @samp{klogind} and @samp{kshd} take an @samp{-e} option
to control encryption; because of the design of the servers, it works
slightly differently. The Kerberos login service listens on two
different ports, one for encrypted connections, and one for unencrypted
connections. Because @samp{klogind} is started by @samp{inetd}, it
needs to know whether it is servicing an encrypted or unencrypted
connection. Thus, the @samp{-e} option tells @samp{klogind} that it is
listening to the encrypted port. Typically, systems that allow both
encrypted and unencrypted logins have two lines in @file{inetd.conf},
one for the @samp{klogin} service and one for the @samp{eklogin}
service. The line for the @samp{eklogin} service uses the @samp{-e}
option, while the line for the @samp{klogin} service does not. Systems
only supporting encrypted logins simply have the @samp{eklogin} line.
On the other hand, @samp{kshd} listens to encrypted and
unencrypted requests on the same port; information from the client
identifies the connection's encryption status. So, @samp{kshd}
interprets the @samp{-e} option to mean that encryption is required. If
this option is specified, unencrypted connections are dropped. Thus,
specifying @samp{-e} to @samp{kshd} is like only having a line for
@samp{eklogin}.
@menu
* Checksums:: Checksum facility for dealing with active attacks.
* BSD Utility Configuration Example:: Sample @file{inetd.conf} entries for BSD utilities.
@end menu
@node Checksums, BSD Utility Configuration Example, BSD Utilities, BSD Utilities
@subsubsection Checksums
Under previous versions of Kerberos, it was possible for an active
attacker to change certain information in the initial authentication
exchange without this change being detected. Starting with Kerberos V5,
Beta6, this information is protected by a checksum passed in the
Kerberos authenticator. Ideally, the server could detect the presence
of this checksum and use it if it were present. This way,
administrators could be sure to use new clients that produced the
checksum, while users who were not as concerned about security could use
a wider range of clients.
This is how the checksum feature works by default.
Unfortunately, clients previous to Kerberos V5, Beta5 used the checksum
field to incorporate semi-random data into the Kerberos authentication
exchange. It is impossible to distinguish these bogus checksums from
checksums that have been produced by modern clients, but modified by an
active attacker. Thus, the checksum feature is incompatible with
previous releases of Kerberos V5. Three modes of operation are provided
to meet the configuration needs of different sites:
@enumerate
@item
The @samp{-c} option to both @samp{kshd} and @samp{klogind} requires
that checksums be present and valid. This only works with clients more
recent than Kerberos V5, Beta6. An error will be given when an older
client tries to connect. This option is incompatible with Kerberos V4;
Kerberos V4 clients do not include a checksum. If this option is used
in conjunction with the @samp{-4} option for Kerberos V4 compatibility,
a warning about the configuration error will be logged on each
connection.
@item
If no checksum-related option is specified, then checksums will be
validated if they are present, but not required. This is compatible with
Kerberos V4 and Kerberos V5 clients as early as Kerberos V5, Beta5.
@item
If the @samp{-i} option is provided, then checksums are ignored, even if
present. This option is required to maintain compatibility with clients
older than Kerberos V5 Beta5. Site should upgrade to newer clients so
this option is not required.
@end enumerate
@node BSD Utility Configuration Example, , Checksums, BSD Utilities
@subsubsection BSD Utility Configuration Example
This section includes sample entries for @file{/etc/inetd.conf}.
Sample configuration are presented for three systems. Note that while
the examples stretch over multiple lines, an entry for a single service
should be placed on only one line in @file{inetd.conf}. Also, not all
systems have all of the columns shown in the example. @xref{Installing
the Sample Application}, for details on adding services to
@file{inetd.conf}.
The first system enables all security features. Only Kerberos
V5 encrypted connections are enabled, and checksums are required.
@example
eklogin stream tcp nowait root
[K_SERVER]/klogind klogind -5 -e -c
kshell stream tcp nowait root
[K_SERVER]/kshd kshd -5 -e -c
@end example
The second system enables encrypted services for both Kerberos
V5 and Kerberos V4. Checksums are not required, but since no V5 clients
earlier than Beta5 are used, they are not ignored.
@example
eklogin stream tcp nowait root
[K_SERVER]/klogind klogind -5 -4 -e
kshell stream tcp nowait root
[K_SERVER]/kshd kshd -5 -4 -e
@end example
The final example has both encrypted and unencrypted services
enabled for both Kerberos V5 and Kerberos V4. Checksums are disabled to
preserve compatability with older V5 clients.
@example
eklogin stream tcp nowait root
[K_SERVER]/klogind klogind -5 -4 -i -e
klogin stream tcp nowait root
[K_SERVER]/klogind klogind -5 -4 -i
kshell stream tcp nowait root
[K_SERVER]/kshd kshd -5 -4 -i
@end example
@node Telnet and FTP, , BSD Utilities, Installing Kerberos Applications
@subsection Telnet and FTP
The following are example entries for @file{inetd.conf} for the
@samp{telnetd} and @samp{ftpd} servers. @xref{Installing the Sample
Application}, for details on adding services to @file{inetd.conf}. Note
that unlike other @file{inetd.conf} examples in this document, these
line should replace existing lines for password-based services of the
same name.
The first example only allows encrypted or authenticated connections.
@example
telnet stream tcp nowait root
[K_SERVER]/telnetd telnetd -a user
ftp stream tcp nowait root
[K_server]/ftpd ftpd -a
@end example
The second example also allows password-based connections to be
made.
@example
telnet stream tcp nowait root
[K_SERVER]/telnetd telnetd
ftp stream tcp nowait root
[K_server]/ftpd ftpd
@end example
@node Common Kerberos Service Names, , Installing Kerberos Applications, Installation
@section Common Kerberos Service Names
The following service names are used by Kerberos client/server
applications.
@table @code
@item host
Used by @samp{telnet}, @samp{rlogin}, @samp{rsh}, @samp{rcp}, @samp{ftp}
and other services which generally give login access to the host.
@item pop
Used by the Post Office Protocol.
@item sample
Used by the Kerberos sample applications.
@end table
These service names are used as the first component of the server's
principal name, with the second component being the server's fully
qualified domain name, in lower case.
@node Troubleshooting, , Installation, Top
@chapter Troubleshooting
@b{To be written.}
@contents
@bye