Windows – Does changing the Primary DNS Suffix of a Windows Server 2012 machine require a reboot

ping -a w.x.y.z

Should resolve the name from the IP address if the reverse lookup zone has been set up properly. If the reverse lookup zone does not have an entry for the record, the -a will just ping without a name.

I found the problem, it was a rogue DHCP server. An intern was trying out the "Open Stack" cloud system which default configures a DHCP server. I guess he tried to isolate it from the network, but didn't do a good enough job because a few random DHCP messages between his server and clients were getting on the main network and setting only the domain name (not an ip) on my clients. Strange thing is that it was not responding to normal DHCP requests from clients on my subnet, he must've partially isolated his "Open Stack" traffic.

We found it with a packet trace in wireshark and searching for the string "novalocal" in packet details. It showed up in a few DHCP, SSDP, LLMNR, and NBNS packets to give us a few IP's and mac addresses to hunt down. I then viewed the mac table in my switches to find his port and go have a chat about the network problems his test was causing. We're isolating his test network with a separate router to prevent further leaks of his local broadcast traffic onto my LAN.