Microsoft KB Archive/241888

= Cable Modem Dynamic Host Configuration Protocol Clients Are Unable to Obtain Lease =

Article ID: 241888

Article Last Modified on 3/1/2007

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APPLIES TO


 * Microsoft Windows NT Server 4.0 Standard Edition
 * Microsoft Windows NT Workstation 4.0 Developer Edition
 * Microsoft Windows NT Server 4.0 Enterprise Edition
 * Microsoft Windows 98 Standard Edition
 * Microsoft Windows 95

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This article was previously published under Q241888



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, click the following article number to view the article in the Microsoft Knowledge Base:

152734 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

Keywords: kberrmsg kbfix kbhardware kbnetwork kbprb KB241888

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