Event ID 20036 with Small Business Server DHCP Server (177610)

SYMPTOMS

Your Microsoft Small Business Server (SBS) does not start the Dynamic Host Configuration Protocol (DHCP) server service and Event Viewer logs the following error:

Event ID : 20036
Source : DHCP Server
Description: The DHCP Server is shutting down because another DHCP Server with IP Address <IP Address> is active on the network.

CAUSE

Your SBS computer has detected another DHCP server on the network and shut down its DHCP Server. This can also be caused by a router on the network that has DHCP or DHCP spoofing capabilities enabled. This causes the Small Business Server's DHCP server to think that there is another DHCP server on the network.

RESOLUTION

This is a design feature of Microsoft Small Business Server. The DHCP server service is automatically installed and configured when Small Business Server is installed. To prevent the accidental installation of a DHCP server on a network with an existing IP addressing scheme, the DHCP server service is designed to shut down when another DHCP server is detected on the network.

You cannot have multiple DHCP servers on the same network when one of the DHCP servers is a Small Business Server DHCP server. To install multiple DHCP servers on your network, you must use the standard retail version of Microsoft Windows NT Server for your DHCP servers and not the DHCP server from Small Business Server.

MORE INFORMATION

The DHCP server service detects other DHCP servers by issuing a DHCP Discover broadcast when the service is started, and again every five minutes after the service has been started. If a response is received, the service is stopped. This behavior is by design and cannot be modified in the Small Business Server.