Windows Server DFS <unknown site>

TL;DR DFS Namespace does not recognise the AD Site (appear as site <unknown> in mmc) that the servers reside in, so clients can get connected to the wrong site file server via drive mapping to namespace occasionally which is not ideal as it's the remote site is over VPN link and slow



Having some issues with Windows AD DFS, hope someone can help, otherwise I'm going to have to call in one of those Microsoft Incident Support and eat the cost as my customer is starting to get a little annoyed.



Have a small network with 2AD sites linked by VPN (OpenVPN via the gateway device)

2 DC in main site, 1 fileserver (2016) all Hyper V

1 DC in branch office, 1 fileserver (2012 R2) all Hyper V



The AD Sites have been created, DC's put in correct ones and subnets set up for each site

I have verified where AD thinks the servers are by nltest successfully



I have successfully set up the DSR Namespace and Replication between the two servers which is working away merrily, but I have a strange issue. The clients have mapped drives to \\mydomain.local\files\relevant share but if I check the DFS on the properties of the drive sometimes they are using the remote fileserver and not the local one, which they should get connected to because of the site they are local to via the subnet as far as I am aware.



I noticed that in the DFS mmc the two file servers are in site <unknown> I think this is where the problem lies. I tried creating a new namespace but the same issue occurred.



Anyone know of a way to edit via ADSI to get them into the correct site, which should then stop my client OCs from connecting to the incorrect fileserver? Or any other fix?

Some of the clients travel between the the two sites regularly with laptops hence my need for the namespace, my idea was to use it so that the mappings target would remain transparent to them when they connect in either office

Thanks