We recently migrated from SBS 2003 to Server 2012 Essentials.
In the days of SBS 2003, it was handling DHCP and DNS. The router/firewall is now handling DHCP.
We are seeing some strange and unexplainable DNS issues.
The server is showing incorrect DNS records for a lot of the computers. I will delete them and they show back up at some point. To make it more confusing (or maybe less), I THINK it is showing the SAME ip address each time and I recognize them from before.
For example, I know at one point we gave Computer 1 a static ip address of 192.168.1.15 (but have since changed it back to DHCP). The server will show 192.168.5.15 - but the REAL ip address of the computer is 192.168.5.133
DHCP is NOT enabled on the server.
DHCP is enabled on the router.
NO Static IP addresses are assigned on the router.
The old server is NOT connected.
I know there is more info you are going to need but I'm not sure what it is.