Microsoft KB Archive/189594

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Article ID: 189594

Article Last Modified on 11/1/2006


  • Microsoft Windows NT Server 4.0, Terminal Server Edition
  • Microsoft Routing and Remote Access Service Update for Windows NT Server 4.0
  • Microsoft Windows NT Server 4.0 Standard Edition

This article was previously published under Q189594


This article contains a copy of the Routing and Remote Access Upgrade for Microsoft Windows NT 4.0 Server Hotfix Pack 3.0 Release Notes. For your convenience, the English version of this post-Service Pack 3 (SP3) hotfix has been posted to the following Internet location. However, Microsoft recommends that you install Windows NT 4.0 Service Pack 4 (SP4) to correct this problem.


Routing and Remote Access Upgrade 3.0 for Microsoft Windows NT(r) 4.0 Server Release Notes

Please use this document to address questions which may arise during the installation of this Routing and Remote Access Upgrade 3.0 for Microsoft Windows NT 4.0 Server.


  • Information on Installation
  • Security Features in this Upgrade
  • Fixes and Features included from Hotfix Update 2.0
  • Known Problems in the 2.0 Hotfix Update
  • Fixes and Features included from Hotfix Update 1.0

Information on Installation

This upgrade requires that you already have Routing and Remote Access Service (RRAS) for Windows NT 4.0 Server installed on your system. Note that you must first apply the Windows NT 4.0 PPTP Upgrade before you apply the RRAS upgrade 3.0.

IMPORTANT:Do not to restart your computer between installations of the Windows NT PPTP upgrade and the RRAS upgrade.

For more information, please refer to the following article in the Microsoft Knowledge Base:

ARTICLE-ID: 189595
TITLE : PPTP Performance & Security Upgrade for WinNT 4.0 Release Notes

This release includes the features and fixes from both the Routing and Remote Access Hotfix Update 1.0 and 2.0 releases and is packaged in an auto-install format. Copy the Upgrade to a temporary directory, and double-click the executable name or type the executable name rrasfixi.exe for x86, or rrasfixa.exe for alpha at a command prompt to install.

The files can also be extracted from the Upgrade pack without installing them. To do this, copy the Upgrade to a temporary directory, and type rrasfixi /x or rrasfixa /x at a command prompt. After extracting the files, the Upgrade can be installed by typing hotfix at a command prompt.

To uninstall this upgrade, extract the files to a directory using the /x command as mentioned above and then type HOTFIX -Y from the same directory you copied the files to.

Output of HOTFIX -?:

HOTFIX [-y] [-f] [-n] [-z] [-q] [-m] [-l]

      -y Perform uninstall (only with -m or -q)
      -f Force apps closed at shutdown
      -n Do not create uninstall directory
      -z Do not reboot when update completes
      -q Quiet Mode -- no user interface
      -m Unattended mode
      -l List installed hotfixes

Security Features in this Upgrade

This upgrade provides several RAS/PPTP security enhancements for the Routing and Remote Access Upgrade for Microsoft Windows NT 4.0 Server. This upgrade also includes the performance improvements and other fixes that were included in previously released hotfixes.

  • A new version of MSCHAP (MSCHAP V2) has been implemented for VPN connections. This new protocol provides mutual authentication, stronger initial data encryption keys, and different encryption keys for the transmit and receive paths. To minimize the risk of password compromise during MSCHAP exchanges, MSCHAP V2 drops support for the MSCHAP password change V1, and will not transmit the LMHash encoding of the password.

For VPN connection requests, a Windows NT server offers MSCHAP V2 before offering the legacy MSCHAP. Updated Windows clients (all platforms) accepts MSCHAP V2 when it is offered. This behavior affects only VPN connections; dial-up connections are not affected.

  • A new registry key, SecureVPN, has been defined to force use of MSCHAP V2. When this variable is absent it has a default value of zero. When set to one on a Windows NT server, this registry key causes the server to drop any VPN connections that do not authenticate using MSCHAP V2. This prevents legacy VPN clients from presenting their credentials in an MSCHAP (or CHAP or PAP) exchange, and is a likely configuration for networks that require a more secure authentication method for VPN connections.

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\RasMan\PPP DWORD: SecureVPN Value: 0x00000001 == force MSCHAP V2 for VPN connections Value: 0x00000000 == do not force secure MSCHAP V2 (defaul

When set to one on a Windows NT 4.0 client, the SecureVPN registry key forces the client to use MSCHAP V2 for all VPN (PPTP) connections. Dial-up connections are not affected by this registry setting.

NOTE: Most users do not need to use the Secure VPN flag. This flag should be used with care because it affects the behavior of all VPN connections from a client. In general, the required use of MSCHAP V2 can be enforced more easily on the server.

  • This release also provides a registry variable, UseLmPassword, which can be set to prevent clients from sending the LM response to a legacy MSCHAP challenge or in an MSCHAP change password exchange. When this variable is absent it has a default value of one, allowing use of the LM response (in order to maintain compatibility with legacy systems).

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\RasMan\PPP\Chap DWORD: UseLmPassword Value: 0x00000001 == send LMHash of the password (default) Value: 0x00000000 == do not send LMHash of the passwo

Setting this variable to zero on a server causes the server to drop any connection request which uses the LM response in an MSCHAP exchange. Setting this variable to zero on a client prevents the client from using LM responses in MSCHAP exchanges. This variable affects both dial-up and VPN connections.

NOTE: Most users do not need to use this registry variable. The new secure mode MSCHAP V2 will not send the LMHash response, so this registry value is most useful when connecting to older access servers which use the original MSCHAP.

  • Other fixes in this upgrade:

Two-way authentication with Demand-Dial Interfaces has been corrected in this upgrade.

Fixes and Features included from Hotfix Update 2.0

NT Issues Performance Issues

  • This release includes an enhancement to TCP/IP that improves the performance of TCP-based applications over high latency and networks that experience high packet loss, such as the Internet.

Routing Issues

  • Added new Demand dial filters. You can now keep demand dial interfaces from dialing by setting filters using the Routemon.exe command with a new "Filtertype= Dial" option. The new syntax for this is the same for setting Input and Output filters using Routemon.exe, and can be seen by typing routemon ip set filter /? at a command prompt.

The following is an example of the syntax used to prevent a demand dial interface from dialing:

C:\>routemon ip add filter myremoterouter dial any

C:\>routemon ip set filter myremoterouter dial forward

NOTE: The first example above is one line; it has been wrapped for readability.

For more information on using the Routemon.exe command to set filters, please see the Routing and Remote Access Administrator's Guide.

  • Added the capability to filter fragmented IP packets. Two registry keys control this functionality.

DWORD: EnableFragmentChecking Value: 0x00000001 == enables fragment checks Value: 0x00000000 == disables fragment checks (defaul
DWORD: DefaultForwardFragments Value: 0x00000001 == filterdriver forwards fragments (default) Value: 0x00000000 == filterdriver drops fragments if they don't match a previous head

  • Changes were made to the Router's Remote Authentication Dial-In User Service (RADIUS) client to resolve a duplicate Acct-Session-Id accounting problem, as well as an issue that caused the reversal of the Framed-IP-Address returned from a RADIUS server. In addition, the RADIUS client has been enhanced to now support the transmission of the NAS-Port-Type and Acct-Session-Time attributes.
  • Resolved issue that used to cause an Access Violation notice when adding a Virtual Interface right after configuring an Area under OSPF routing.
  • Adjusted the RIP Authentication type to 2 instead of 1, per RFC 1388.

NOTE: This upgrade must be applied to all Routing and Remote Access routers if you are using RIP2 authentication.

  • Resolved issue which could cause Mprouter to stop responding when doing an ipconfig /release
  • Made an improvement that ensures that periodic RIP route updates resumes each time a demand-dial interface is reactivated.

Known Problems in the 2.0 Hotfix Update

  • Although there is a checkbox in the Global IP Config dialog to enable/disable filtering, at this time the only functionality it has is to visually show you if any filters have been configured on your interface(s). Regardless, the filter driver is always enabled. In order to disable filtering on an interface, you must use the per interface option in the Interface IP Config dialog.
  • Even though the "Filtertype= Dial" option has been properly configured for a demand dial interface using Routemon.exe, it may still be possible for that interface to dial. This only occurs if you are pinging from the command line of the Routing and RAS server in which the demand dial interface is configured.

Fixes and Features included from Hotfix Update 1.0

New Features Added in Hotfix 1.0

  • Allowing PPP clients to connect without authentication

This can be accomplished by altering the default registry key as shown:
DWORD: ForceEncryptedPassword Value: 0x00000003 == allows the server to accept incoming PPP clients without authenticatio

  • Using MS-CHAP with RADIUS authentication

In order to enable MS-CHAP with RADIUS authentication, you must add a registry value:
DWORD: OfferMSCHAP Value: 0x00000001 == Once this is enabled every incoming PPP connection will be offered MS-CHAP, and MS-CHAP will be used to authenticate each PPP user against the RADIUS server that your RAS server is usin

List of Issues Fixed in Hotfix Update 1.0

All bug fixes contained in hotfix 1.0 are listed below. You can query the Microsoft Knowledge Base (KB) to find an article about a specific bug by using the KB Qxxxxxx number that is assigned to the bug. The Microsoft Knowledge Base can be located at the following Microsoft Web site at:

KB# Brief Description
172290 Routing and Remote Access "Out of Buffers" Event Logs
176689 RRAS Requires hotfix when Using Proxy 2.0
173533 WinNT Radius Client Sends Incomplete Accounting Information
176506 Radius Accounting Only Logs One Entry for Multilink Client
173532 Radius Authentication Causes Access Violation in Mprouter.exe
172512 Routing and Remote Access Event ID 20100
176502 RAS Authentication Rechallenge Resets Compression Flag
176209 RAS or RRAS Server Fails to Answer Incoming Calls
167038 RAS Clients Run Winsock and RPC Applications Slowly
171061 RIP Does Not Advertise Zero Subnets
160517 RRAS May Decrement Local Static Route Metric
176082 RRAS Server Updates Link State Database but not Route Table
162834 RRAS Stops Routing After Encountering Zero Checksum
104296 RRAS Uses Larger MTU Than Other OSPF Routers

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