Microsoft KB Archive/125514

= TCP/IP-32 Client Cannot Obtain DHCP Lease =

Article ID: 125514

Article Last Modified on 11/17/2003

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APPLIES TO


 * Microsoft Windows NT Server 3.5
 * Microsoft TCP/IP for Windows for Workgroups 3.11a
 * Microsoft Windows for Workgroups 3.11

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This article was previously published under Q125514



SUMMARY
A Microsoft Windows for Workgroups client using Microsoft TCP/IP-32 Dynamic Host Configuration Protocol (DHCP) on the same network segment as a Microsoft Windows NT 3.5 DHCP Server may not be able to obtain an IP address lease if the DHCP server is incorrectly configured.



MORE INFORMATION
If the DHCP server is assigned a Class B IP address, it must also have its DHCP scope configured for Class B addresses or it will not respond with an offer message when it receives a discover message from a DHCP client.

Example
A DHCP server is assigned a Class B IP address. However, it is configured to lease DHCP clients Class C IP addresses, that is, its DHCP scope is configured as Class C. Because the DHCP client is on the same segment, its discover message is not routed and thus the giaddr field is not modified by an RFC 1542 compliant router. Noticing that the giaddr field has not been modified, the server assumes the client is on the same subnet and uses its own IP information (IP address and subnet mask) for its DHCP offer message.

Additional query words: prodtcp32 prodtcp 3.11 wfw wfwg TCP/IP fail

Keywords: KB125514

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