I have a domain controller running Windows 2012 R2 in a VM. I installed SEP with full protection on the DC. Then I lost DNS in my network. I can run nslookup on the server and it finds stuff no problem. When I run nslookup on any computer on my network I get DNS request timed out. timeout was 2 seconds. Default Server: UnKnown Address: 192.168.1.90 (which is the correct address) and when I try to lookup any URL I get Server: UnKnown Address: 192.168.1.90 and four DNS request timed out message and finally Request to UnKnown timed-out. I assumed it was because SEP with full protection includes a firewall that was blocking the DNS requests. I uninstall SEP (which ended with a reboot of the VM). I checked the firewall in the control panel and it was turned off. I tried a ping -a 192.168.1.90 and it correctly reported the name of the server and it had ping responses and times of a couple of ms.