The DHCP Server automatically recognizes changes in the IP configuration in Windows. This is done based on the Windows API NotifyAddrChange. This API tells the DHCP Server when an IP configuration is changing. The DHCP Server acts on this by internally shutting down and restarting itself. Upon restart, the new configuration is used. In order to not shutdown and restart unneccessarily the DHCP Server uses a timeout mechanism to delay the shutdown after NotifyAddrChange events.

[Settings]
NotifyTimeout=5000  ; Default: 1000 (milliseconds)

The default of this timeout is 1 second (1000 millisends). Some network cards are very slow and require a longer delay before they are actually ready to run. Set the NotifyTimeout value to a larger timeout period to compensate for this.