I have inherited a AD environment and our existing sites and services has servers DC within Default first sites and NTDS is setup. However I do not see subnets setup. Don't I need subnets setup to fully take advantage of AD replication to DC? We have a total of 7 DC and 5 are distributed throughout a VLAN network at different buildings. Two are at a different locations and on a separate VLAN. We are running Windows server 2008 and 2003 on two DC.