Windows 95/98 DHCP Client Modified for RFC2131 Retransmission Compliance

ID: Q194790

The information in this article applies to:

Microsoft Windows 98
Microsoft Windows 95

SYMPTOMS

Windows 95 or Windows 98-based computers using Dynamic Host Configuration Protocol (DHCP) may occasionally fail to lease an Internet Protocol (IP) address when the network or DHCP server is very busy.

CAUSE

This issue can occur because the DHCP client-retry mechanism in Windows 95 and Windows 98 is not in compliance with RFC 2131.

The current behavior is as follows:

Windows 95 running the standard Winsock 1.1 stack:

- DHCP Request: 1 retry after 2 seconds
- DHCP Discover: 3 retries, at 2-second intervals

Windows 98, and Windows 95 with the Winsock 2.0 update:

- DHCP Request: 1 retry after 6 seconds
- DHCP Discover: 3 retries, at 6-second intervals

RESOLUTION

A supported fix that corrects this problem for Windows 98 and for Windows 95 with the Windows Sockets 2.0 Update is now available from Microsoft, but has not been fully regression tested and should be applied only to computers experiencing this specific problem. To resolve this problem immediately, contact Microsoft Technical Support to obtain the fix. If you are not severely impacted by this specific problem, Microsoft recommends that you wait for the next service pack that contains this fix.

For a complete list of Microsoft Technical Support phone numbers and information on support costs, please go to the following address on the World Wide Web:

http://support.microsoft.com/support/supportnet/default.asp

This fix, for Windows 98 only, should have the following file attributes (or later):


   File name     Version    Date      Time     Size
   ---------------------------------------------------------
   Vdhcp.386     4.10.2012  06/22/98  01:12pm  56,175 bytes

This fix, for Windows 95 with the Windows Sockets 2.0 update only, should have the following file attributes (or later):


   File name     Version    Date      Time     Size
   ---------------------------------------------------------
   Vdhcp.386     4.10.1658  10/20/98  10:25am  55,155 bytes

NOTE: This version of the Vdhcp.386 file is only compatible with Windows 95-based computers that have been updated to the Windows Sockets 2.0 version of the TCP/IP stack. For more information about this update, please see the following article in the Microsoft Knowledge Base:

ARTICLE-ID: Q182108
TITLE : Availability of Windows Sockets 2.0 for Windows 95

NOTE: If you contact Microsoft to obtain this fix, a fee may be charged. This fee is refundable if it is determined that you only require the fix you requested. However, this fee is non-refundable if you request additional technical support, if your no-charge technical support period has expired, or if you are not eligible for standard no-charge technical support.

For more information about eligibility for no-charge technical support, see the following article in the Microsoft Knowledge Base:

ARTICLE-ID: Q154871
TITLE: Determining If Your Product Is Eligible for No-Charge Technical Support

STATUS

Microsoft has confirmed this to be a problem in Windows 98 and Windows 95.

This problem was corrected in Windows 98 Second Edition.

MORE INFORMATION

After you apply the fix listed earlier in this article, the DHCP client retry mechanism is modified to be comply with RFC 2131.

The current Windows NT DHCP client (Dhcpcsvc.dll) behaves as described in RFC 2131. It sends the first DHCP request plus up to 3 retries if needed.

For additional information about issues resolved by updates to this component, please see the following articles in the Microsoft Knowledge Base:

ARTICLE-ID: Q158713
TITLE : Fatal Exception Error Using DHCP

ARTICLE-ID: Q147872
TITLE : Unable to Lease IP Address from DHCP Server

ARTICLE-ID: Q140460
TITLE : Dial-Up Networking Does Not Obtain an IP Address

For additional information about Windows 95 updates, please see the following article in the Microsoft Knowledge Base:

ARTICLE-ID: Q161020
TITLE : Implementing Windows 95 Updates

Additional query words: 98

Keywords : kbnetwork win95 win98
Version : WINDOWS:95
Platform : WINDOWS
Issue type : kbprb