I have five domain controllers running Windows Server 2008 R2. I have also enabled DNS scavenging on one of the DCs.
A few days ago I have noticed that lots of machines are missing in our DNS. But when you ping them, most of them are pingable with hostname, even I can NSLOOKUP as well.
What could be the issue? Is my DHCP not registering new entries. Interestingly, all old machines are missing. Old means, they are still active but they are on network for some time.