On ma, 14 kesä 2021, Ronald Wimmer wrote:
On 14.06.21 13:37, Alexander Bokovoy wrote:
>On ma, 14 kesä 2021, Ronald Wimmer via FreeIPA-users wrote:
>>On 12.06.21 13:08, Florence Renaud via FreeIPA-users wrote:
>>>please refer to External Trusts to Active Directory  from
>>>WIndows Integration guide, it nicely explains the difference
>>>between external trust and forest trust.
>>Sorry for my unspecific initial question. I did read the
>>documentation. As I understood it the external trust somehow
>>isolates the view on that particular domain.
>>If DomA_Trust is a normal one and DomB_Trust an external one I
>>cannot use DomB users in a DomA group for example, right? If DomB
>>trust was not external I could do that?
>I think you need to start with Active Directory design and
>documentation. In particular, group types in AD define who can be
>included into them and how they can be consumed:
>Type of trust between domains influences the use of groups but group
>scopes are ultimate ones here.
>When applying that to a trust between IPA and AD, remember that we only
>have two trust types:
> - forest trust: IPA domain is in a separate forest than any AD domain
> - external trust: only immediately trusted AD domain users and groups
> can be seen and used for authentication across the trust, there is no
> transitivity into any other trust that this AD domain may have
> anywhere else
>In addition to that, while forest trust in itself is transitive to
>domains in the trusting forest, there is no transitivity across all
>trusting forests. If forest A trusts forest B and forest B trusts forest
>C, there is no trust from forest A to any domain in forest C.
>The same applies to groups from those forests as well, complicated by
>the group scopes.
In our case IPA hast a trust to the forest root of domain A which
itself has a trust to domain B. IPA has an external trust to domain B.
With the AD management tool we are using I can put users of domain B
into a group of domain A.
What matters is where domain B is located. Is it part of the same forest
as domain A? Is it outside of forest A?
When I try to use that particular group (POSIX group that has the AD
group as its member) in a HBAC scenario I do get a permission denied
It can be anything. This information does not give any chance to
understand why there is a problem.
External trust to domain B was setup years ago when we were still
experimenting with IPA. So my first question is if the separate trust
to domain B is needed at all? (because there is a trust from domain A
to domain B on the AD side.) If yes I probably would not want domain B
trust to be an external one in my scenario, would I?
You need to decide what you want. ;) If A and B are in the same forest,
then you don't need an external trust to B from IPA side.
/ Alexander Bokovoy
Sr. Principal Software Engineer
Security / Identity Management Engineering
Red Hat Limited, Finland