Question : Installing new domain controller question

I am installing a new DC at a a remote site. I will be using AD integrated DNS at the site. It is also what we use at the main site.

Do i need to change the server DNS info at the remote site's now to itself before i do dcpromo or do i do it during the dcpromo process?

Answer : Installing new domain controller question

You need to install windows on the new machine, set the DNS on the new machine to point at the existing server and then do DCPROMO. From the command line promote the new machine to a domain controller with the DCPROMO command from the command line Select Additional Domain Controller in an existing Domain

Once Active Directory is installed then to make the new machine a global catalog server, go to Administrative Tools, Active Directory Sites and Services, Expand ,Sites, Default first site and Servers. Right click on the new server and select properties and tick the Global Catalog checkbox. (Global catalog is essential for logon as it needs to be queried to establish Universal Group Membership)

Install DNS on the new server. As you are using Active Directory Integrated DNS on the first Domain Controller, DNS will automatically replicate to the new domain controller along with Active Directory.

Once DNS is installed then you can change the preferred DNS server setting on the new server to point to itself.

Indeed all the clients (and the domain controllers themselves) need to have their Preferred DNS server set to one domain controller (the one in their own site), and the Alternate DNS to the other, that way if one of the DNS Servers fails, the clients will automatically use the other.

Both Domain Controllers by this point will have Active Directory, Global Catalog, DNS and DHCP. and the domain could function for a while at least should any one of them fail.

To prevent unnecessary cross-site athentication you should define your subnets ans sites in Active Directory Sites ans Services, with this done the clients will prefer to authenticate with the domain controller in  their own site.