Active directory not accessible on remote site Domain Controller.
We have 2 x DC's in different locations, connected by an IPSEC VPN - which is not functioning correctly. (Keeps disconnecting but that is a separate issue)
My problem is that on the remote site (site 2), when the VPN is down users cannot authenticate as AD is not accessible. I thought that once AD is sync'd between sites then it would cache AD information on the local server. Have we configured something wrong?
DNS is OK - when the VPN tunnel is operational everything works great and AD is in sync.
Site 1 - Server 2012 R2 - has all the FSMO roles
Site 2 - Server 2016 - is as additional Domain Controller
Any help appreciated.