: This article is for informational use only. It does not contain
any troubleshooting information. If you are searching for troubleshooting
information that is not mentioned in this article, search the Microsoft
Knowledge Base again by using keywords that are listed in the following
Microsoft Knowledge Base article:
How to Query the Microsoft Knowledge Base Using Keywords
information about obtaining the Dial-Up Networking 1.4 Upgrade, click the
article number below to view the article in the Microsoft Knowledge Base:
Dial-Up Networking 1.4 Upgrade Is Available
For additional information about the
update, click the article number below to view the article in the Microsoft
Article List of Problems That Are Fixed By the DUN 1.4 Upgrade
This Dial-Up Networking 1.4 upgrade for Windows 98 supports 128
bit encryption for both dial-up and PPTP connections and resolves situations in
which PPTP connections would no longer transmit data. It includes all of the
features from the earlier Windows 98 Security Upgrade which strengthened
password management and data encryption in PPTP connections. 1.1 New Features in DUN 1.4
1.2 Installation Notes
- 128-bit encryption is supported with the Dial-Up Networking
- The Dial-Up Networking 1.4 Upgrade improves the stability
of PPTP connections.
Execute the Install file and follow the instructions it
displays. At the end of the installation process you will be required to reboot
your PC. 1.3 MSCHAP V2
A new MSCHAP secure mode (MSCHAP V2) has been
implemented, providing mutual authentication, stronger initial data encryption
keys, and different encryption keys for the transmit and receive
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 LM password response.
For VPN connections, a PPTP
server will negotiate MSCHAP V2 before negotiating the original MSCHAP. An
updated Windows 98 client will accept this offer and use MSCHAPV2 as the
authentication method. To ensure that no VPN clients authenticate using MSCHAP,
the server can be set to require MSCHAP V2. This will prevent legacy clients
from presenting their credentials in an MSCHAP or PAP or CHAP exchange, and is
a likely configuration for networks that require the most secure authentication
method.1.4 Secure VPN Mode
If there are special circumstances in which you wish to
ensure that your PC uses only the new MSCHAP V2 for all VPN connection
attempts, a new client-side registry flag, SecureVPN, can be used to force this
behavior. When this flag is set, your PC will only accept MSCHAP V2
authentication for any VPN connections. In addition, this flag will require
data encryption for all VPN connections. Dial-up connections are not
: Most users will not need to use the Secure VPN flag. This flag
should be used with care because it will affect the behavior of all VPN
connections from your machine. In general, the required use of MSCHAP V2 and
data encryption can be enforced more easily on the server.
registry setting which forces a Windows 98 client to use only the new MSCHAP V2
secure mode and require data encryption for PPTP connections is defined below.
By default, this registry variable is absent, meaning "do not force secure mode
on PPTP connections". The value of this variable is checked just before a
connection is attempted.
1.5 LM Response Suppression
Value: 0x00000001 == Force secure mode (MSCHAP V2 plus data encryption) on all PPTP connections
Value: 0x00000000 == Do not force secure mode on PPTP connections
This release also provides a new registry variable
which prevents the client from sending the LM response to a legacy MSCHAP
challenge, as defined below. By default, this variable is absent, meaning that
the client should send the LM response (in order to maintain compatibility with
legacy servers). This variable affects both dial-up and VPN connections; its
value is checked just before a connection is attempted.NOTE
: Most users will 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. Setting this variable on a Windows 98 client will prevent the client
from connecting to a Windows 95 or Windows 98 server.
1.6 Forcing Strong Encryption
0x00000000 = Do not send LM challenge response (send only NT challenge response)
0x00000001 = Send LM challenge response
Windows 98 Dial-up Networking already supports a
checkbox to require encryption for a specific connection. Clients which support
128-bit encryption will accept any level of encryption (128-bit or 40-bit)
offered by the server. This upgrade provides a new registry flag,
ForceStrongEncryption. When set, this flag will require 128-bit encryption for
any connection which has already been set to require encryption. (In other
words, setting the new registry flag essentially changes the meaning of the
existing checkbox from "require encryption" to "require strong
The registry flag which forces strong encryption is
defined below. By default, the flag is absent. The value of this flag is
checked just before a connection is attempted.
1.7 Other Changes
0x00000000 = No effect; does not force strong encryption
0x00000001 = Requires 128-bit encryption for any connection which already requires encryption
The details section of the connection status display
has been modified to identify the specific form of CHAP that was used in the
connection. Standard CHAP is displayed as "Challenge Authentication Protocol";
legacy MSCHAP is displayed as "Microsoft Challenge Authentication Protocol";
and MSCHAP V2 is displayed as "Microsoft Mutual Challenge Authentication
Protocol". 1.8 Removing this Update
To uninstall the Dial-Up Networking 1.4 upgrade for
Windows 98, use the "Add/Remove Programs" application in the control panel.
This will remove 128 bit encryption (leaving the capability for 40 bit
encryption) and will restore Dial-up Networking files to the versions that
originally shipped with Windows 98.start -> control panel -> Add/Remove Programs -> Install/Uninstall Tab -> Select "Dial-up Networking 1.4 Update for Windows 98" -> Click "Add/Remove" button
Information in this document is subject to change without notice and is
Provided for informational purposes only. The entire risk of the use or
results of the use of this document remains with the user, and Microsoft
Corporation makes no warranties, either express or implied. The names
of companies, products, people, characters, and/or data mentioned herein
are fictitious and are in no way intended to represent any real
individual, company, product, or event, unless otherwise noted.
Complying with all applicable copyright laws is the responsibility of
the user. No part of this document may be reproduced or transmitted in
any form or by any means, electronic or mechanical, for any purpose,
without the express written permission of Microsoft Corporation.
Microsoft may have patents, patent applications, trademarks,
copyrights, or other intellectual property rights covering subject
matter in this document. Except as expressly provided in any written
license agreement from Microsoft, the furnishing of this document does
not give you any license to these patents, trademarks, copyrights,
or other intellectual property.
Copyright 2001 Microsoft Corporation. All rights reserved.
Microsoft, MS-DOS, MS, Windows, Windows NT, Windows 2000 are either
Registered trademarks or trademarks of Microsoft Corporation in the
U.S.A. and/or other countries.
The Windows 98 PPTP client is based on code developed by 3Com Corp.
Other product and company names mentioned herein may be the trademarks
of their respective owners.