Microsoft KB Archive/837361

= Kerberos protocol registry entries and KDC configuration keys in Windows Server 2003 =

Article ID: 837361

Article Last Modified on 2/2/2007

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APPLIES TO


 * Microsoft Windows Server 2003, Datacenter Edition (32-bit x86)
 * Microsoft Windows Server 2003, Enterprise Edition (32-bit x86)
 * Microsoft Windows Server 2003, Standard Edition (32-bit x86)

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Important This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 Description of the Microsoft Windows Registry



SUMMARY
This article contains information about registry entries that relate to the Kerberos version 5 authentication protocol in Microsoft Windows Server 2003.



INTRODUCTION
Kerberos is an authentication mechanism that is used to verify user or host identity. Kerberos is the preferred authentication method for services in Windows Server 2003.

If you are running Windows Server 2003, you can modify Kerberos parameters to help troubleshoot Kerberos authentication issues or to test the Kerberos protocol. To do this, add or modify the registry entries that are listed in the &quot;More Information&quot; section.



MORE INFORMATION
Warning If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

Note After you finish troubleshooting or testing the Kerberos protocol, remove any registry entries that you add. Otherwise, performance of your computer may be affected.

Registry entries and values under the Parameters key
The registry entries that are listed in this section must be added to the following registry subkey:

Note If the Parameters key is not listed under Kerberos, you must create the key.
 * Entry: SkewTime

Type: REG_DWORD

Default Value: 5 (minutes)

This value is the maximum time difference that is permitted between the client computer and the server that accepts Kerberos authentication. In Windows 2000 checked build version, the default SkewTime value is 2 hours.

Note A checked build version of the Windows operating system is used in production and testing environments. (A checked build is also known as a debug version.) A checked build has many compiler optimizations turned off. This kind of build helps trace the cause of problems in system software. A checked build turns on many debugging checks in the operating system code and in the system drivers. These debugging checks help the checked build identify internal inconsistencies as soon as they occur. A checked build is larger and is slower to run than an end-user version of Windows.

An end-user version of Windows is also known as a free build version or a retail-build version. In a free build version, debugging information is removed, and Windows is built with full compiler optimizations. A free build version is faster and uses less memory than a checked build version.
 * Entry: LogLevel

Type: REG_DWORD

Default Value: 0

This value indicates whether events are logged in the system event log. If this value is set to any non-zero value, all Kerberos-related events are logged in the system event log.
 * Entry: MaxPacketSize

Type: REG_DWORD

Default Value: 1465 (bytes)

This value is the maximum User Datagram Protocol (UDP) packet size. If the packet size exceeds this value, TCP is used.
 * Entry: StartupTime

Type: REG_DWORD

Default Value: 120 (seconds)

This value is the time that Windows waits for the Key Distribution Center (KDC) to start before Windows gives up.
 * Entry: KdcWaitTime

Type: REG_DWORD

Default Value: 10 (seconds)

This value is the time Windows waits for a response from a KDC.
 * Entry: KdcBackoffTime

Type: REG_DWORD

Default Value: 10 (seconds)

This value is the time between successive calls to the KDC if the previous call failed.
 * Entry: KdcSendRetries

Type: REG_DWORD

Default Value: 3

This value is the number of times that a client will try to contact a KDC.
 * Entry: DefaultEncryptionType

Type: REG_DWORD

Default Value: 23 (decimal) or 0x17 (hexadecimal)

This value indicates the default encryption type for pre-authentication.
 * Entry: FarKdcTimeout

Type: REG_DWORD

Default Value: 10 (minutes)

This is the time-out value that is used to invalidate a domain controller from a different site in the domain controller cache.
 * Entry: NearKdcTimeout

Type: REG_DWORD

Default Value: 30 (minutes)

This is the time-out value that is used to invalidate a domain controller in the same site in the domain controller cache.
 * Entry: StronglyEncryptDatagram

Type: REG_BOOL

Default Value: FALSE

This value contains a flag that indicates whether to use 128-bit encryption for datagram packets.
 * Entry: MaxReferralCount

Type: REG_DWORD

Default Value: 6

This value is the number of KDC referrals that a client pursues before the client gives up.
 * Entry: KerbDebugLevel

Type: REG_DWORD

Default Value: 1 for Windows Server 2003 checked build version, 0 for Windows Server free build version

This value indicates whether debug logging is on (1) or off (0).
 * Entry: MaxTokenSize

Type: REG_DWORD

Default Value: 12000 (Decimal)

This value is the maximum value of the Kerberos token. Microsoft recommends that you set this value to less than 65535.
 * Entry: SpnCacheTimeout

Type: REG_DWORD

Default Value: 15 minutes

This value is the lifetime of the Service Principal Names (SPN) cache entries. On domain controllers, the SPN cache is disabled.
 * Entry: S4UCacheTimeout

Type: REG_DWORD

Default Value: 15 minutes

This value is the lifetime of the S4U negative cache entries that are used to restrict the number of S4U proxy requests from a particular computer.
 * Entry: S4UTicketLifetime

Type: REG_DWORD

Default Value: 15 minutes

This value is the lifetime of tickets that are obtained by S4U proxy requests.
 * Entry: RetryPdc

Type: REG_DWORD

Default Value: 0 (false)

Possible values: 0 (false) or any non-zero value (true)

This value indicates whether the client will contact the primary domain controller for Authentication Service Requests (AS_REQ) if the client receives a password expiration error.
 * Entry: RequestOptions

Type: REG_DWORD

Default Value: Any RFC 1510 value

This value indicates whether there are additional options that must be sent as KDC options in Ticket Granting Service requests (TGS_REQ).
 * Entry: ClientIpAddress

Type: REG_DWORD

Default Value: 0 (This setting is 0 because of Dynamic Host Configuration Protocol and network address translation issues.)

Possible values: 0 (false) or any non-zero value (true)

This value indicates whether a client IP address will be added in AS_REQ to force the Caddr field to contain IP addresses in all tickets.
 * Entry: TgtRenewalTime

Type: REG_DWORD

Default Value: 600 seconds

This value is the time that Kerberos waits before it tries to renew a Ticket Granting Ticket (TGT) before the ticket expires.
 * Entry: AllowTgtSessionKey

Type: REG_DWORD

Default Value: 0

Possible values: 0 (false) or any non-zero value (true)

This value indicates whether session keys are exported with initial or with cross realm TGT authentication. The default value is false for security reasons.

Registry entries and values under the Kdc key
The registry entries that are listed in this section must be added to the following registry subkey:

Note If the Kdc key is not listed under Services, you must create the key.  Entry: KdcUseClientAddresses

Type: REG_DWORD

Default Value: 0

Possible values: 0 (false) or any non-zero value (true)

This value indicates whether IP addresses will be added in the Ticket-Granting Service Reply (TGS_REP). Entry: KdcDontCheckAddresses

Type: REG_DWORD

Default Value: 1

Possible values: 0 (false) or any non-zero value (true)

This value indicates whether IP addresses for the TGS_REQ and the TGT Caddr field will be checked. Entry: NewConnectionTimeout

Type: REG_DWORD

Default Value: 50 (seconds)

This value is the time that an initial TCP endpoint connection will be kept open to receive data before it disconnects. Entry: MaxDatagramReplySize

Type: REG_DWORD

Default Value: 1465 (decimal, bytes)

This value is the maximum UDP packet size in TGS_REP and Authentication Service Replies (AS_REP) messages. If the packet size exceeds this value, the KDC returns a KRB_ERR_RESPONSE_TOO_BIG message that requests that the client switch to TCP. Entry: KdcExtraLogLevel

Type: REG_DWORD

Default Value: 2

Possible values:  1 (decimal) or 0x1 (hexadecimal): Audit SPN unknown errors.</li> 2 (decimal) or 0x2 (hexadecimal): Log PKINIT errors. (PKINIT is an Internet Engineering Task Force (IETF) Internet draft for &quot;Public Key Cryptography for Initial Authentication in Kerberos.&quot;)</li> 4 (decimal) or 0x4 (hexadecimal): Log all KDC errors.</li></ul>

This value indicates what information the KDC will write to event logs and to audits.</li> Entry: KdcDebugLevel

Type: REG_DWORD

Default Value: 1 for checked build, 0 for free build

This value indicates whether debug logging is on (1) or off (0).

If the value is set to 0x10000000 (hexadecimal) or 268435456 (decimal), specific file or line information will be returned in the edata field of KERB_ERRORS as PKERB_EXT_ERROR errors during a KDC processing failure.</li></ul>

Keywords: kbwinservnetwork kbsecurityservices kbregistry kbinfo KB837361

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