If you want to deploy domain controllers in an area of your network that is remote from the hub site, you can create a site object in Active Directory Domain Services (AD DS) to represent the local area network (LAN) in the remote area. You must configure the site to include the subnet addresses that are assigned on the remote LAN. When you create a new site object, you must place the site into an existing site link. If you already have multiple sites, you may have to create an additional site link to connect the new site to an existing site.
After you create a new site, when you add the Active Directory Domain Services server role to a server that has an IP address that maps to that site, you can specify that the server object for the new domain controller is created in the site according to its IP address. As an alternative, you can select the site for the new domain controller and then configure its IP address to an address that maps to a subnet in that site.
The procedures in this section have the following requirements:
The network address or addresses (in the form network address/prefix). These addresses form the subnet object names when you create subnets.
A site link. To create a site, you must add the new site to an existing site link. You can use the default site link (DEFAULTIPSITELINK) if no other site link exists. If you have more than two existing sites and you are adding a site, you might add the site to an existing site link and then create a new site link and associate the new site with that site link. In most cases, you then remove the new site from the old site link.
The transport protocol that is available for replication over the site link. When a wide area network (WAN) link is available between the sites, use the IP transport. When connectivity is intermittent or when end-to-end IP connectivity is not available, you can use Simple Mail Transfer Protocol (SMTP) for replication to the site. However, SMTP replication has restrictions. For more information about using SMTP replication, see Understanding Replication Between Sites.
To add a site to a forest, perform the following procedures: