On 07/12/2016 08:58, freeIPA users list wrote:
On ke, 07 joulu 2016, List dedicated to discussions about use, configuration and deployment of the IPA server. wrote:
I know the Quick Start Guide and Deployment Recommendations cover this in
depth, but there are still some ambiguities.

I'm trying to figure out if a company like us, lautus.net should use a DNS
subdomain like ipa.lautus.net for the IPA domain, or not.
It is really depending on your deployment details.

If you already have some other Kerberized environment in place and you
are not going to replace it by FreeIPA, then you need to make sure that
new FreeIPA deployment would not conflict with the existing one.
Or if you think there's a chance you might want to add another Kerberized environment later (e.g. "ad.lautus.net")


should continue to be hosted by DNS servers elsewhere that delegate say,
ipa.lautus.net to FreeIPA.
The question of whether you host ipa.lautus.net DNS (or indeed lautus.net DNS) in FreeIPA is a different issue.

If you're happy with your existing DNS infrastructure, then you can either delegate ipa.lautus.net to your FreeIPA servers (with NS records); or run FreeIPA without DNS, and simply import the ipa.lautus.net SRV records directly into the lautus.net domain.

Having FreeIPA host the ipa.lautus.net domain means these SRV records are populated automatically, but it's not really that hard to add them to an existing DNS service.

OTOH, if you *don't* already have a good authoritative internal DNS service with a UI that you like, then you might want to use FreeIPA for this anyway. You can easily create extra zones in FreeIPA.

I would be a bit wary about putting FreeIPA servers out on the public Internet though. For one thing, the default config is an open resolver (which you can tighten easily enough). I also have a deep distrust of Java, but maybe that's just me.



But on the other hand the same doc is full of examples where a Kerberos
realm like EXAMPLE.COM (instead of IPA.EXAMPLE.COM) is used, i.e example
2.2. of secion 2.3.4. But the same guide also says that the Kerberos realm should be the same as the ipa DNS domain, just uppercased. So example 2.2.
implies that example.com is running their DNS domain on FreeIPA, for
everything, not just for IPA SRV and TXT entries.
The Kerberos realm always has a corresponding DNS domain, so realm IPA.LAUTUS.NET has a corresponding DNS domain "ipa.lautus.net".

But with FreeIPA you can still manage hosts called foo.lautus.net or bar.int.lautus.net. At worst you'd have some extra [domain_realm] mappings in krb5.conf

(Aside: Active Directory is much more fussy, and basically doesn't work if the hosts don't have hostnames within the same DNS domain as their kerberos realm - and indeed have reverse DNS as well as forward)


And when ipa-client-install is run on somehost.lautus.net, it also defaults
to LAUTUS.NET for Kerberos domain, as if the default expectation is that
your toplevel company DNS name would be your kerberos domain.
But you can override that.



And when I install a trial IPA server on host ipa-server-1.lautus.net using
"ipa-server-install --setup-dns --realm IPA.LAUTUS.NET --domain
ipa.lautus.net --forwarder=8.8.8.8", and then look at the DNS Zones in the Web UI, I see not only ipa.lautus.net, but also lautus, with record "@ NS
ipa-server-1.lautus.net". In other words the IPA server defaults to
thinking it owns the domain above ipa.lautus.net too. Which goes against
2.3.1 above.
Interesting. What does "ipa dnszone-find --pkey-only" show?

It seems like it's created an authoritative zone both for the server's own domain (lautus.net if the server is xxx.lautus.net) as well as the realm's domain (ipa.lautus.net)

I don't know why it's doing that. Now I've checked with another system here: the hostname is "ipa-1.int.example.com" and the realm is "ipa.example.com", and you're right, it is authoritative for both:

  Zone name: int.example.com.
  Zone name: ipa.example.com.

This isn't what I wanted. The int.example.com domain is hosted externally and I didn't want to override it. Right now it's hiding all names in int.example.com that it doesn't know about.

I would expect that it's possible to remove this zone, but I'd need to test that doesn't stop other hosts called xxx.int.example.com from joining.

Yes and no. What you see with "@ NS ..." is a glue record -- you are
supposed to have a glue record for IPA domain in the upstream domain,
this is how domain delegation works in DNS world.
Aside: technically that's not a glue record. A glue record is an A or AAAA record when the NS record points to a host within the subdomain which is being delegated. It is to solve the chicken-and-egg situation of how to contact a nameserver for a domain before you've contacted a nameserver for the domain.

In your case, if you already have working DNS for lautus.net, then you don't want FreeIPA to be authoritative for lautus.net as well.

Regards,

Brian.

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