publish DFS resource in an external trusted domain


I'm implementing DFS in a local domain (test laboratory) and I'm working with it without any problem inside this domain, but according to my company setup, I would like that my DFS was reacheable from the corporate domain. My domain has a trust relationship with the corporate one (separate forests). The trust type is External and No transitive (the users from the corporate domain an access to the resources from the local domain).

The question is if there is a way to publish in the corporate domain my DFS service... When I try to get it from any resource in the corporate domain, I get a network error "Windows cannot access \\mydomain\dfsroot"...

Thanks in advanced.
Who is Participating?
Lester_ClaytonConnect With a Mentor Commented:
I'm afraid you cannot do this - DFS shares are only accessible from the same domain that they're published.

What you CAN however do is create a DFS Namespace in the domain, and then add the folder of the trusted domain's server.

For example:

Domain A:

DFS Namespace: \\\Root
DFS Folder \\\Root\Folder = \\\Data$

Domain B:

DFS Namespace: \\\Root
DFS Folder: \\\Root\Folder = \\\Data$

Now you can access the same location on either domain using the path \\%USERDNSDOMAIN%\Root\Folder
ecemibmAuthor Commented:
That's what I suspect... thanks for the confirmation and the way to do it.
It seems that my other self was incorrect.

It *is* possible to access DFS shares cross domain or cross forest, as long as you have either prepared the DFS Root properly, or if you use one of the workarounds.

The reason why it doesn't work by default is because when creating DFS roots, the referalls are not being created using Fully Qualified Domain Names - they're created using just servernames, which naturally, anybody outside of the domain won't be able to resolve.

Here is the correct way of doing it:

How to configure DFS to use fully qualified domain names in referrals

This will require a recreation of the DFS root.

As far as workarounds are concerned, you have 2 options:

Option 1: DNS Search Scopes.

What you can do is add the target DFS's domain name to the DNS Suffix Search List of all clients in the requesting domain.  Modifying DHCP to add the DNS domain as a DNS Suffix is the easiest way to do this.  

For example, if you have a DNS root which is \\\blah (which server is serving), then the referral will be \\a01\blah, and the clients in will try to resolve and then - thus getting the referral to work.

Option 2 : CNames

Another option is to create a CName in the requesting domain to point to the A record in the target domain.

For example, if you have a DNS root which is \\\blah (which server is serving), then the referral will be \\a01\blah.  The clients in will try to resolve, and this will normally fail.  What you do here is create a CNAME for a01 in's zone, and make it resolve to  Resolution will now work as will the referrals.

I apologise for my erroneous answer from last year.
Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

All Courses

From novice to tech pro — start learning today.