Hi,
our company was merged with another firm and the joint entity has a need for a domain name change.
I am planning to create a new forest (new parent domain), create forest trusts between the new and current, and slowly migrate over to the new.
This new forest will be created on the same existing physical network infrastructure and topology. my question relates to the subnet configuration on the Active Directory Sites and Services for the existing domain.
for network 'simplicity' (we have multiple physical sites all connected via a layer 2 VPLS WAN, delivered over a layer 3 architecture), i dont wish to change the class B subnet. ie all our firewall, routing setup for all sites falls under the 10.61.0.0 network. with each site having a /19 subnet. i.e: SiteA 10.61.0.0 /19; siteB 10.61.32.0 /19; siteC 10.61.64.0 /19, siteD 10.61.96.0 /19, siteE 10.61.128.0 /19, site F 10.61.160.0 /19
these subnets are also configured at the Active Directory Sites and Services snap-in
So - if i were to create a new forest/domain, can i use an ip range within these existing subnets. so long as they are not currently in use? e.g.:
current Domain Controller has IP: 10.61.45.5 mask 255.255.255.0. Can the new Domain Controller for new forest/domain be assigned on the currently unused range 10.61.45.0 mask 255.255.255.0? (both will be on separate vlans at the switch level)
OR (as i fear) because 10.61.46.x is a range within the current siteB subnet for the current domain scope, then issues will arise because of this overlap. And hence my ONLY alternative is to replicate these site IPs using another class B network e.g. 10.62.0.0