DOCUMENT:Q241888  08-MAY-2002  [winnt]
TITLE   :Unable to Obtain DHCP Lease When Using a Cable Modem
PRODUCT :Microsoft Windows NT
PROD/VER:WINDOWS:95; winnt:4.0
OPER/SYS:
KEYWORDS:kberrmsg kbhw kbnetwork kbHardwarekbfixlist

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The information in this article applies to:

 - Microsoft Windows NT Server version 4.0 
 - Microsoft Windows NT Workstation version 4.0 
 - Microsoft Windows NT Server, Enterprise Edition version 4.0 
 - Microsoft Windows 98 
 - Microsoft Windows 95 
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SYMPTOMS
========

When you connect to a network using a cable modem, you may be unable to obtain a
Dynamic Host Configuration Protocol (DHCP) address from a Windows NT-based DHCP
server. The Windows NT-based DHCP client may generate the following error
message:

   The DHCP client was unable to obtain an IP network address from a DHCP
   server.

Also, the Windows NT-based DHCP server may generate the following error message:

   WSAEMSGSIZE - Error 10040

CAUSE
=====

This issue occurs because the cable modem DHCP client is sending a DHCPDISCOVER
packet that is larger than 576 bytes, and the Windows NT-based DHCP server is
not able to correctly process the large packet. The WSAEMSGSIZE error message
may appear when the buffer size is not large enough to accommodate the receiving
datagram.

RESOLUTION
==========

To resolve this problem, obtain the latest service pack for Windows NT 4.0. For
additional information, please see the following article in the Microsoft
Knowledge Base:

   Q152734 How to Obtain the Latest Windows NT 4.0 Service Pack


STATUS
======

This problem was first corrected in Windows NT 4.0 Service Pack 6.

MORE INFORMATION
================

Microsoft Windows NT DHCP server is in compliance with RFC 2131, which specifies
the maximum length of a DHCP packet to be 576 bytes. This fix is being
implemented as a proactive step to prevent this issue. This is a server fix, and
it should only be applied to Windows NT-based DHCP servers.

Additional query words: winsock 2.0 4.00

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Keywords          : kberrmsg kbhw kbnetwork kbHardware kbfixlist
Technology        : kbWinNTsearch kbWinNTWsearch kbWinNTW400 kbWinNTW400search kbWinNT400search kbWinNTSsearch kbWinNTSEntSearch kbWinNTSEnt400 kbWinNTS400search kbWinNTS400 kbWin95search kbWin98search kbZNotKeyword3 kbWin98
Version           : WINDOWS:95; winnt:4.0
Hardware          : ALPHA x86
Issue type        : kbprb
Solution Type     : kbfix

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