This is far easier than it sounds.

As long as you never want to see any angusclark.com website or host names from anywhere not connected to your private network, just use that domain name in freeipa and and hosts and their ip addresses to freeipa dns. Now when any system on your private network looks for myhost.angusclark.com they get the address from your internal only dns. From outside, that myhosts.angusclark.com host doesn't exist.

Unless you set your freeipa dns as the nameserver in your domain hosting setup, outside will only get a default parked page for web lookup and nothing else.

Assuming your private network does actually have a need for internet access and you do have a gateway set up and it acts as your default router, then you will want to add an upstream dns server in your freeipa dns setup to resolve the non-angusclark.com addresses. Your freeipa dns server will only request data from the upstream source as required. It will never see a (legitimate) request from upstream since you never published the freeipa server dns as being available.

Note: any system with internet access will get probed for security holes. Use good network hygiene and block ports on the systems that should not be seen from the internet.

On December 27, 2021 3:27:14 PM EST, Angus Clarke via FreeIPA-users <freeipa-users@lists.fedorahosted.org> wrote:
Hi Rafael

I appreciate your response but we're (just me?) still lacking in direction as to how to properly use your software in the real world - to me It feels like an admins vs devs topic although I could easily be missing something :)

I mention the Microsoft documentation because i haven't found anything on this topic in RedHat land. I just remember the MS docs being the only source of useful information when last I checked.


Ok let's try this:

I've just registered angusclarke.com with a public DNS provider and am ready to deploy FreeIPA for my corporate network which uses a private IP space. How do I do this?

According to this
https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/networking_guide/ch-configure_host_names#sec-Recommended_Naming_Practices

then I should have a domain delegated to me, but I am not a public DNS provider, I'm just Angus Clarke ... Nor do I want my private IP space available to be looked up in a public DNS record ... And I'd rather have my private IP records handled by my internal DNS system - all of this is standard practise for companies and individuals however I dont think this topic is suitably addressed in the redhat documentation - I see a disconnect in the recommendation pasted above vs the installation documentation for FreeIPA.

Maybe I've missed it, maybe I can promote the topic here and it can be championed in the right direction, maybe I can even help on the topic myself.

Regards
Angus



From: Rafael Jeffman <rjeffman@redhat.com>
Sent: Monday, 27 December 2021, 8:15 pm
To: Angus Clarke
Cc: FreeIPA users list; Dave Mintz; Peter Larsen
Subject: Re: [Freeipa-users] Re: DNS and FreeIPA

Hello Angus,

On Mon, Dec 27, 2021 at 11:31 AM Angus Clarke <angus@charworth.com> wrote:
Hi Rafael

What is not clear to me is how to integrate FreeIPA with a real public DNS domain, which I think is what Dave is referring to as he mentioned he owns a legitimate domain. In any case, AFAIK we're not supposed to use made up domains for internal DNS anymore ...

Although you shouldn't use a domain name you don't own, if your DNS
server is not visible outside of your network, the issues you have with
domain names would be contained to your local network (like not being
able to access 'awellknowsearch.com' if you use this domain name in
your own network).


 
I see the docs talk about server.idm.example.com - presumably example.com is supposed to be some legitimate DNS domain and idm.example.com is a delegated subdomain, although this doesn't appear to be explained. Microsoft docs talk about using delegated subdomains of legitimate public DNS domains for internal corporate DNS, which is what got me into this train of thought in the first place.

Delegating a subdomain to a private IP (your internal DNS server) and hiding that delegation with a split view on your public DNS is one way of hiding the subdomain from public view whilst keeping all your private DNS data private and hosted/managed in house. Whether you use FreeIPA's DNS for internally hosting idm.example.com or not is a matter of choice I suppose.

A delegated subdomain is simply a subdomain for which the authoritative
DNS server is not the same as the main domain. I'm not sure about which
Microsoft docs you mention, but on Azure, subdomain delegation might be
required depending on what you want to do on Azure. For private
subdomains, if you have full control of the domain/hosts, there might not
be a need to delegate the subdomain (as in Peter Larsen's message).

Also, if you consider using split view, FreeIPA DNS should not be used, and
if you use an external DNS any configuration should be carried on that DNS
provider, so it is not a matter of configuring DNS within FreeIPA. The
discussion on configuring FreeIPA DNS only makes sense if using FreeIPA's
integrated DNS.
 
Whilst I'm here and at the opposite end of this topic, I run bad.domain for our FreeIPA DNS domain (going back years to the original installation) with the realm BAD - I'm getting a bit uncomfortable about this configuration and wondered if I'll drop out of support at some point - any thoughts on that? (I surely can't be the only one!)

I haven't used FreeIPA's DNS.

If you don't use FreeIPA's DNS, there is no problem in using whatever
your DNS nameserver supports, as long as FreeIPA entries are correct
and accessible. You may find which records need to be available with
`ipa dns-update-system-records --dry-run`.

Hope this helps,

Rafael


Thanks
Angus





From: Rafael Jeffman via FreeIPA-users <freeipa-users@lists.fedorahosted.org>
Sent: Monday, 27 December 2021, 1:31 pm
To: FreeIPA users list
Cc: Dave Mintz; Peter Larsen; Rafael Jeffman
Subject: [Freeipa-users] Re: DNS and FreeIPA

Sorry for the top reply, but this is more an overview about all messages
than a direct answer. Everything here assumes you are using FreeIPA's
integrated DNS.

First, it was suggested that split view DNS is used. Don't do that, as it
is not supported by FreeIPA. Use it only if you manage your own external
DNS, without using FreeIPA to manage entries.

Regarding forwarding DNS queries, the easiest way is to set a global
forwarder. In my home lab I use public ones, like Google and Cloudflare,
and I'm not much concerned about external traffic, so I leave the default
configuration, "forward first", enabled.

You can find more information about the available options here:


A lot more about working with DNS can be found


Regards,

Rafael


On Mon, Dec 27, 2021 at 1:40 AM Dave Mintz via FreeIPA-users <freeipa-users@lists.fedorahosted.org> wrote:
Hi Peter,

Thank you so much! 
Could you please elaborate on how to configure the FreeIPA DNS server to forward only non-local-domain queries?

In the DNS Global Configuration there is the Forward policy
Forward first
Forward only
Forwarding disabled

Which one should be used to do what you say below?
Do I need to set a Global forwarder?

Best,
Dave


> On Dec 26, 2021, at 10:00 PM, Peter Larsen via FreeIPA-users <freeipa-users@lists.fedorahosted.org> wrote:
>
> On Sun, 2021-12-26 at 14:16 -0500, Dave Mintz via FreeIPA-users wrote:
>> Hello,
>> I have been trying to set up FreeIPA on an internal CentOS 8 server.
>> I was successful in getting it running, I set up DNS for internal
>> queries.  It worked.  However, when I tried to set up SSL certs I ran
>> into issue.
>>
>> My question is this: 
>> I own a legitimate domain.
>> It is not “hosted”.
>> I have no intention of exposing any of my internal servers to the
>> Internet.
>> How do I go about configuring the DNS at my registrar so that when I
>> configure my internal servers, including FreeIPA, DNS, SSL, email,
>> etc., any requests that go out to the Internet will resolve
>> correctly?
>>
>> Any help or pointers to documentation would be greatly appreciated.
>
> I have freeIPA with DNS over several replication instances running. The
> domains are like yours mostly internal and not to resolve externally.
> Without a lot of boring details, you do not need to register your TLD
> if you just use the domain internally. As long as the resolver your
> internal hosts point to is your authoritative DNS server that FreeIPA
> manages, the clients will get responses as they need.
>
> This requires your server not to just blindly forward all DNS
> externally. I have forward turned off on my domains. This means when a
> client requests a public DNS address, the bind server managed by
> FreeIPA will do a NS lookup to see where the request needs to be sent.
> It's not 1.1.1.1 or similar services doing that. Works great for a
> small network where your domain is 100% internal.
>
> You can have an external NS too and they can provide very different
> answers. Perhaps you just want MX to resolve externally but an ocean of
> internal addresses should not. If someone outside your network tries to
> resolve an address, they will hit the external resolver (not managed by
> FreeIPA!) and only resolve what it knows about.
>
>
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--
Rafael Guterres Jeffman
Senior Software Engineer 
FreeIPA - Red Hat




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