Cable Modem Dynamic Host Configuration Protocol Clients Are Unable to Obtain Lease (241888)

The information in this article applies to:

Microsoft Windows NT Server 4.0
Microsoft Windows NT Workstation 4.0
Microsoft Windows NT Server, Enterprise Edition 4.0
Microsoft Windows 98
Microsoft Windows 95

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.

Modification Type:	Minor	Last Reviewed:	12/20/2004
Keywords:	kberrmsg kbfix kbHardware kbnetwork kbprb KB241888