285 lines
11 KiB
Plaintext
285 lines
11 KiB
Plaintext
@c $Id: win2k.texi,v 1.12 2001/01/28 22:10:35 assar Exp $
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@node Windows 2000 compatability, Acknowledgments, Migration, Top
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@comment node-name, next, previous, up
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@chapter Windows 2000 compatability
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Windows 2000 (formerly known as Windows NT 5) from Microsoft implements
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Kerberos 5. Their implementation, however, has some quirks,
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peculiarities, and bugs. This chapter is a short summary of the things
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that we have found out while trying to test Heimdal against Windows
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2000. Another big problem with the Kerberos implementation in Windows
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2000 is that the available documentation is more focused on getting
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things to work rather than how they work and not that useful in figuring
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out how things really work.
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This information should apply to Heimdal @value{VERSION} and Windows
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2000 Professional. It's of course subject all the time and mostly consists of
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our not so inspired guesses. Hopefully it's still somewhat useful.
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@menu
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* Configuring Windows 2000 to use a Heimdal KDC::
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* Inter-Realm keys (trust) between Windows 2000 and a Heimdal KDC::
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* Create account mappings::
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* Encryption types::
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* Authorization data::
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* Quirks of Windows 2000 KDC::
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* Useful links when reading about the Windows 2000::
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@end menu
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@node Configuring Windows 2000 to use a Heimdal KDC, Inter-Realm keys (trust) between Windows 2000 and a Heimdal KDC, Windows 2000 compatability, Windows 2000 compatability
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@comment node-name, next, precious, up
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@section Configuring Windows 2000 to use a Heimdal KDC
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You need the command line program called @code{ksetup.exe} which is available
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in the file @code{SUPPORT/TOOLS/SUPPORT.CAB} on the Windows 2000 Professional
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CD-ROM. This program is used to configure the Kerberos settings on a
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Workstation.
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@code{Ksetup} store the domain information under the registry key:
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@code{HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\LSA\Kerberos\Domains}.
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Use the kadmin program in Heimdal to create a host principal in the
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Kerberos realm.
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@example
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unix% kadmin
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kadmin> ank -pw password host/datan.my.domain
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@end example
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You must configure the Workstation as a member of a workgroup, as opposed
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to a member in an NT domain, and specify the KDC server of the realm
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as follows:
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@example
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C:> ksetup /setdomain MY.REALM
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C:> ksetup /addkdc MY.REALM kdc.my.domain
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@end example
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Set the machine password, i.e. create the local keytab:
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@example
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C:> ksetup /setmachpassword password
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@end example
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The workstation must now be rebooted.
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A mapping between local NT users and Kerberos principals must be specified,
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you have two choices:
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@example
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C:> ksetup /mapuser user@@MY.REALM nt_user
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@end example
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This will map a user to a specific principal, this allows you to have
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other usernames in the realm than in your NT user database. (Don't ask
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me why on earth you would want that...)
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You can also say:
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@example
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C:> ksetup /mapuser * *
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@end example
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The Windows machine will now map any user to the corresponding principal,
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for example @samp{nisse} to the principal @samp{nisse@@MY.REALM}.
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(This is most likely what you want.)
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@node Inter-Realm keys (trust) between Windows 2000 and a Heimdal KDC, Create account mappings, Configuring Windows 2000 to use a Heimdal KDC, Windows 2000 compatability
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@comment node-name, next, precious, up
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@section Inter-Realm keys (trust) between Windows 2000 and a Heimdal KDC
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See also the Step-by-Step guide from Microsoft, referenced below.
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Install Windows 2000, and create a new controller (Active Directory
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Server) for the domain.
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By default the trust will be non-transitive. This means that only users
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directly from the trusted domain may authenticate. This can be changed
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to transitive by using the @code{netdom.exe} tool.
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You need to tell Windows 2000 on what hosts to find the KDCs for the
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non-Windows realm with @code{ksetup}, see @xref{Configuring Windows 2000
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to use a Heimdal KDC}.
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This need to be done on all computers that want enable cross-realm
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login with @code{Mapped Names}.
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Then you need to add the inter-realm keys on the Windows kdc. Start the
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Domain Tree Management tool. (Found in Programs, Administrative tools,
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Active Directory Domains and Trusts).
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Right click on Properties of your domain, select the Trust tab. Press
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Add on the appropriate trust windows and enter domain name and
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password. When prompted if this is a non-Windows Kerberos realm, press
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OK.
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Do not forget to add trusts in both directions.
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You also need to add the inter-realm keys to the Heimdal KDC. There are
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some tweaks that you need to do to @file{krb5.conf} beforehand.
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@example
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[libdefaults]
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default_etypes = des-cbc-crc
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default_etypes_des = des-cbc-crc
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@end example
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since otherwise checksum types that are not understood by Windows 2000
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will be generated (@xref{Quirks of Windows 2000 KDC}.).
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Another issue is salting. Since Windows 2000 does not seem to
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understand Kerberos 4 salted hashes you might need to turn off anything
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similar to the following if you have it, at least while adding the
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principals that are going to share keys with Windows 2000.
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@example
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[kadmin]default_keys = des3:pw-salt des:pw-salt des:pw-salt:
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@end example
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You must also set:
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Once that is also done, you can add the required inter-realm keys:
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@example
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kadmin add krbtgt/NT.REALM.EXAMPLE.COM@@EXAMPLE.COM
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kadmin add krbtgt/REALM.EXAMPLE.COM@@NT.EXAMPLE.COM
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@end example
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Use the same passwords for both keys.
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Do not forget to reboot before trying the new realm-trust (after running
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@code{ksetup}). It looks like it might work, but packets are never sent to the
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non-Windows KDC.
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@node Create account mappings, Encryption types, Inter-Realm keys (trust) between Windows 2000 and a Heimdal KDC, Windows 2000 compatability
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@comment node-name, next, precious, up
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@section Create account mappings
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Start the @code{Active Directory Users and Computers} tool. Select the
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View menu, that is in the left corner just below the real menu (or press
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Alt-V), and select Advanced Features. Right click on the user that you
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are going to do a name mapping for and choose Name mapping.
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Click on the Kerberos Names tab and add a new principal from the
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non-Windows domain.
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@node Encryption types, Authorization data, Create account mappings, Windows 2000 compatability
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@comment node-name, next, previous, up
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@section Encryption types
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Windows 2000 supports both the standard DES encryptions (des-cbc-crc and
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des-cbc-md5) and its own proprietary encryption that is based on MD4 and
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rc4 that is documented in and is supposed to be described in
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@file{draft-brezak-win2k-krb-rc4-hmac-03.txt}. New users will get both
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MD4 and DES keys. Users that are converted from a NT4 database, will
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only have MD4 passwords and will need a password change to get a DES
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key.
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Heimdal implements both of these encryption types, but since DES is the
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standard and the hmac-code is somewhat newer, it is likely to work better.
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@node Authorization data, Quirks of Windows 2000 KDC, Encryption types, Windows 2000 compatability
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@comment node-name, next, previous, up
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@section Authorization data
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The Windows 2000 KDC also adds extra authorization data in tickets.
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It is at this point unclear what triggers it to do this. The format of
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this data is only available under a ``secret'' license from Microsoft,
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which prohibits you implementing it.
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A simple way of getting hold of the data to be able to understand it
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better is described here.
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@enumerate
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@item Find the client example on using the SSPI in the SDK documentation.
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@item Change ``AuthSamp'' in the source code to lowercase.
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@item Build the program.
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@item Add the ``authsamp'' principal with a known password to the
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database. Make sure it has a DES key.
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@item Run @kbd{ktutil add} to add the key for that principal to a
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keytab.
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@item Run @kbd{appl/test/nt_gss_server -p 2000 -s authsamp
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--dump-auth=file} where file is an appropriate file.
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@item It should authenticate and dump for you the authorization data in
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the file.
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@item The tool @kbd{lib/asn1/asn1_print} is somewhat useful for
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analyzing the data.
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@end enumerate
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@node Quirks of Windows 2000 KDC, Useful links when reading about the Windows 2000, Authorization data, Windows 2000 compatability
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@comment node-name, next, previous, up
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@section Quirks of Windows 2000 KDC
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There are some issues with salts and Windows 2000. Using an empty salt,
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which is the only one that Kerberos 4 supported and is therefore known
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as a Kerberos 4 compatible salt does not work, as far as we can tell
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from out experiments and users reports. Therefore, you have to make
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sure you keep around keys with all the different types of salts that are
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required.
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Microsoft seems also to have forgotten to implement the checksum
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algorithms @samp{rsa-md4-des} and @samp{rsa-md5-des}. This can make Name
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mapping (@pxref{Create account mappings}) fail if a @code{des-cbc-md5} key
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is used. To make the KDC return only @code{des-cbc-crc} you must delete
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the @code{des-cbc-md5} key from the kdc using the @code{kadmin
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del_enctype} command.
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@example
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kadmin del_enctype lha des-cbc-md5
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@end example
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You should also add the following entries to the @file{krb5.conf} file:
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@example
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[libdefaults]
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default_etypes = des-cbc-crc
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default_etypes_des = des-cbc-crc
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@end example
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These configuration options will make sure that no checksums of the
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unsupported types are generated.
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@node Useful links when reading about the Windows 2000, , Quirks of Windows 2000 KDC, Windows 2000 compatability
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@comment node-name, next, previous, up
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@section Useful links when reading about the Windows 2000
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There are lots of text about Kerberos on Microsoft's web site, here is a
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short list of the interesting documents that we have managed to find.
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@itemize @bullet
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@item Step-by-Step Guide to Kerberos 5 (krb5 1.0) Interoperability -
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@url{http://www.microsoft.com/windows2000/library/planning/security/kerbsteps.asp}
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Kerberos GSS-API (in Windows-ize SSPI), Windows as a client in a
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non-Windows KDC realm, adding unix clients to a Windows 2000 KDC, and
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adding cross-realm trust (@xref{Inter-Realm keys (trust) between Windows 2000
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and a Heimdal KDC}.).
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@item Windows 2000 Kerberos Authentication -
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@url{http://www.microsoft.com/TechNet/win2000/win2ksrv/technote/kerberos.asp}
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White paper that describes how Kerberos is used in Windows 2000.
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@item Overview of kerberos -
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@url{http://support.microsoft.com/support/kb/articles/Q248/7/58.ASP}
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Links to useful other links.
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@item Klist for windows -
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@url{http://msdn.microsoft.com/library/periodic/period00/security0500.htm}
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Describes where to get a klist for Windows 2000.
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@item Event logging for kerberos -
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@url{http://support.microsoft.com/support/kb/articles/Q262/1/77.ASP}.
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Basicly it say that you can add a registry key
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@code{HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa\Kerberos\Parameters\LogLevel}
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with value DWORD equal to 1, and then you'll get logging in the Event
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Logger.
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@item Access to the active directory through LDAP
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@url{http://msdn.microsoft.com/library/techart/kerberossamp.htm}
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@end itemize
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Other useful programs include these:
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@itemize @bullet
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@item pwdump2
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@url{http://www.webspan.net/~tas/pwdump2/}
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@end itemize
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