[Freeipa-users] FreeIPA and AD trusts on the same DNS domain

[Alston, David]

Greetings!

     Thanks for clarifying.  That makes more sense now.

     I'm still not sure what sorts of headaches I would be running into if I do have FreeIPA and AD both managing servers in the company.com domain.  Somehow I need to find out if these are just mild headaches, or if they are incapacitating migraines that will drive us all insane.

--David Alston

-----Original Message-----
From: Simo Sorce [mailto:simo at redhat.com] 
Sent: Thursday, August 04, 2016 4:31 AM
To: Alston, David
Cc: freeipa-users at redhat.com
Subject: Re: [Freeipa-users] FreeIPA and AD trusts on the same DNS domain

On Wed, 2016-08-03 at 15:22 -0500, Alston, David wrote:
> Greetings!
> 
> >> 2. Active Directory must never know anything about a DNS domain
> 
> >> freeipa.company.com (I'm not sure why)
> 
> > Correct because if that happened then AD considers the whole
> subdomain as part of its realm and trust routing will not work.
> 
> 
> Doesn't that mean that we have to have the FreeIPA servers on their 
> own DNS domain again?

No, you can use the Windows DNS, DNS management != AD Domain, what matters is that AD never had that DNS name as a child domain, with computer objects in it.

>   So we can't have linux-server.company.com and 
> windows-server.company.com (managed by FreeIPA and AD respectively) 
> because there has to be a SOA for .company.com somewhere and that is 
> already managed by AD (in our environment).

No you can't have this (if you want SSO and avoid headaches in general) no matter what you do. You have to keep server names on separate (sub)domains.
In some cases you can use CNAMEs though.

>      Also, thanks for your other answers.  They were very helpful :^)

You are welcome,
Simo.

> --David Alston
> 
> 
> -----Original Message-----
> From: Simo Sorce [mailto:simo at redhat.com]
> Sent: Wednesday, August 03, 2016 2:13 PM
> To: Alston, David
> Cc: freeipa-users at redhat.com
> Subject: Re: [Freeipa-users] FreeIPA and AD trusts on the same DNS 
> domain
> 
> On Wed, 2016-08-03 at 13:52 -0500, Alston, David wrote:
> > Greetings!
> 
> > 
> 
> >      That sounds like great news!   Just to make sure I understand correctly..
> 
> > 
> 
> > 1. Any server managed by FreeIPA must NEVER have had a computer 
> > object
> 
> > associated with them in AD?  (even if it has now been deleted)
> 
> No, what a random server does or has done is irrelevant in this sense, but see later, for caveats.
> 
> > 2. Active Directory must never know anything about a DNS domain
> 
> > freeipa.company.com (I'm not sure why)
> 
> Correct because if that happened then AD considers the whole subdomain as part of its realm and trust routing will not work.
> 
> > 3. My linux servers being managed by FreeIPA can still have the DNS
> 
> > domain company.com (instead of servername.freeipa.company.com)
> 
> Although the strict answer is yes, if you put a linux server joined to freeIPA in the AD DNS Domain then Single Sign On from Windows users will not work, as AD will consider all request for tickets to those servers as requests for itself and will never return referrals to the freeIPA KDCs for those TGS requests, so clients will not be able to get tickets for those servers. 
> 
> > 4. Single Signon to the Linux servers using AD credentials will 
> > still
> 
> > work
> 
> 
> No, see above.
> 
> > 5. (BONUS) I could even let AD trust user accounts created in FreeIPA?
> 
> 
> Not clear what you mean here. If you mean that IPA user accounts can operate in the Windows domain, the answer is technicaly yes, although because we do not expose (yet) a Global Catalog to the Windows AD servers, it will be hard to set ACLs on the Windows side to actually authorize freeIPA users to login to AD managed computers (it can probably be done via CLI, but not through AD administrative UIs).
> We plan to fix this in the near future by providing a GC service.
> 
> 
> HTH,
> Simo.
> 
> --
> Simo Sorce * Red Hat, Inc * New York
> 


--
Simo Sorce * Red Hat, Inc * New York