Article ID: 197197 - View products that this article applies to.
This article was previously published under Q197197
Dynamic Host Configuration Protocol (DHCP) clients are unable to get IP addresses from DHCP server.
This behavior may be caused by one of the following scenarios:
Scenario 1Changed IP address on DHCP server and now clients cannot get IP addresses.
Scenario 2DHCP clients across router from DHCP server are unable to get an address from the server.
Scenario 3Multiple DHCP servers exist on the LAN.
To resolve each possible cause, use one of these solutions:
Solution for Scenario 1A DHCP server can only service requests for a scope whose network ID is the same as the network ID of its IP address.
Make sure that the server's IP address falls in the same IP network ID as the scope it is servicing. For example, a server with IP address in the 192.168.0.0 network cannot assign addresses from a scope like 10.0.0.0, unless superscoping is used.
For additional information, please see the following articles in the Microsoft Knowledge Base:
(http://support.microsoft.com/kb/139904/EN-US/ )How to Configure Your DHCP Server Scope
(http://support.microsoft.com/kb/169140/EN-US/ )Using DHCP to Assign IP Addresses to Secondary Networks
(http://support.microsoft.com/kb/161571/EN-US/ )Using DHCP "Superscopes" to Serve Multiple Logical Subnets
Solution for Scenario 2A DHCP server can provide IP addresses to client computers spanning multiple subnets if the router that separates them can act as an RFC 1542 (BOOTP) relay agent.
(http://support.microsoft.com/kb/174765/EN-US/ )How to Configure Microsoft DHCP Server for BOOTP Clients
Solution for Scenario 3Make sure that you do not configure multiple DHCP servers on the same LAN with overlapping scopes.
In case of Small Business Server, the DHCP service will automatically stop when it detects another DHCP server on the LAN.
Article ID: 197197 - Last Review: February 27, 2007 - Revision: 2.2
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