If you have installed DHCP failover server on a machine running on windows 10, version 1603, this post is for you:

The latest cumulative update  KB4338814 released on last Patch Tuesday (July 10, 2018) came out with a bunch of quality improvements and security enhancements but also had a bad bug that could potentially disrupt your network connection. 

Microsoft mentioned this bug in their support page as a known issue, quoting "After installing this update on a DHCP Failover Server, Enterprise clients may receive an invalid configuration when requesting a new IP address. This may result in loss of connectivity as systems fail to renew their leases." Since Microsoft has officially terminated its support for Windows 10, version 1603 for home and pro users, only  Windows 10 Enterprise and Education and Windows Server 2016 (and LTSC versions) still receive this update.

Currently, there is no workaround available for this update. The only possible resolution is to block this update from getting installed. If you are using Desktop Central to patch your network, decline this update to your DHCP failover server by following these steps: