I'm working on a project to use DFS file replication between our site and our sister site. Each site has its own domain as forest root, all DC's run Win2012R2:

corp.company.co.uk is one domain and corp.company.de is the other. These domains were set up independantly but now corporate structure has changed, we need to share files and we think DFS is the best way to do it.

The sites are currently joined with a forest trust, over a VPN, authentication and resource sharing work fine through it, but after reading up on DFS I have found out that it does not work between forests.

If I joined both of these domains to a new forest (maybe they could live in the forest of corp.companyGroup.co.uk), would I be able to keep the existing discontiguous domain trees, schemas and SID's etc. without a huge migration project?

It was only supposed to be a small project to get file replication working between the two sites, but my current research suggests that to get DFS working I will have to use ADMT to migrate both domains to the new forest, which will be a big project (~50 users at each site). It will make sense eventually to use contiguous child domains, but I just wanted to verify my thought process before I committed any significant hours to the project.

Many thanks!


You can't join two different Forests together.

You can't create a cross Forest DFS namespace.

There's nothing that says you can't host the DFS namespace in one Forest and access it from the other Forest. If you already have a cross Forest trust as you stated then this is certainly possible.

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  • Thanks for your suggestion, I'll look into hosting the DFS namespace in corp.company.co.uk and accessing it from corp.company.de. – Stevo85 Sep 27 '16 at 7:02
  • Although the main reason we chose DFS file replication was because it uses RDC which means that it's really efficient and doesn't use a lot of bandwidth to synchronise. If I host the DFS namespace in one forest and access it from the other then isn't that like using normal network shares in that we would have to use something like robocopy to sync the files? Thanks – Stevo85 Sep 27 '16 at 7:33
  • No, the data would live in one Domain only, not both, so no syncing of data across Domains is needed. Additionally, you could host one of the file servers from Domain A on the Domain B network so that the shared data is "closer" to the users in Domain B. – joeqwerty Sep 27 '16 at 11:35

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