[Freeipa-users] Ping forwarded domain name.

[Martin Basti]

On 23.11.2016 03:48, TomK wrote:
> On 11/22/2016 10:22 AM, Martin Basti wrote:
>>
>>
>> On 22.11.2016 13:57, TomK wrote:
>>> On 11/22/2016 2:59 AM, Martin Basti wrote:
>>>> Hey,
>>>>
>>>>
>>>> On 22.11.2016 06:33, TomK wrote:
>>>>> Hey Guy's,
>>>>>
>>>>> I'm forwarding a domain dom.abc.xyz from a Windows Server 2012 
>>>>> over to
>>>>> my dual Free IPA server.  The Free IPA servers are authoritative for
>>>>> this subdomain.  The Windows Server 2012 DNS is resolves on abc.xyz
>>>>> and forwards dom.abc.xyz.
>>>> Do you have configured proper zone delegation for subdomain 
>>>> dom.abc.xyz?
>>>> Proper NS and glue records
>>>> http://www.zytrax.com/books/dns/ch9/delegate.html
>>>>
>>>>>
>>>>> I cannot ping dom.abc.xyz.  Everything else, including client
>>>>> registrations, work fine.  If Free IPA is authoritative on
>>>>> dom.abc.xyz, should it not create DNS entries so the sub domain 
>>>>> can be
>>>>> pinged as well?
>>>>
>>>> What do you mean by "ping"?
>>>>
>>>>>
>>>>> /etc/resolv.conf also get's regenerated on reboot on the IPA Servers
>>>>> and wanted to ask if you can point me to some materials online to
>>>>> determine where can I permanently adjust the search to add 
>>>>> dom.abc.xyz
>>>>> to the already present abc.xyz .  I wasn't able to locate what I
>>>>> needed in my searches.
>>>>>
>>>>> I'm using the latest v4.
>>>>
>>>> It depends on what are you using, probably you have NetworkManager 
>>>> there
>>>> that is editing /etc/resolv.conf
>>>>
>>>> https://ask.fedoraproject.org/en/question/67752/how-do-i-add-a-search-domain-using-networkmanager/ 
>>>>
>>>>
>>>>
>>>>
>>>> Martin
>>>
>>>
>>> I Uninstalled NetworkManager.  Still changes.
>>> ping dom.abc.com results in "ping: unknown host"
>>>
>>> I'll have a look at the first link, ty.
>>>
>>
>> ping (ICMP protocol) and DNS system are different things, do you have
>> hostname dom.abc.com with A record or it is a zone?
>>
>> with ping command hostname "dom.abc.com" is resolved to IP address
>> first, do you have A record set for dom.abc.com in zone apex or what are
>> you trying to achieve with ping command?
>>
>> for testing DNS try to use commands: dig, host, nslookup
>>
>> Martin
>>
>
> Apologize for the long reply but it should give some background on 
> what it is that I'm doing.
>
> 1) dom.abc.com is a zone.  There is no A record for dom.abc.com in 
> FreeIPA (Confirmed by Petr).  I get the point Petr Spacek pointed out 
> in his comment as well.  What should it really point too? ( I kind of 
> answer this question below so please read on. )  Where I'm getting 
> this from is that in Windows Server 2012 abc.com returns the IP of any 
> of the participating AD / DNS servers within the cluster (The two 
> Windows Server 2012 are a combined clustered AD + DNS servers.).  
> Being able to resolve abc.xyz is handy.  During a lookup, I can get a 
> list of all the IP's associated with that domain which would indicate 
> all the DNS + AD servers online under that domain or serving that domain:
>
>
> # nslookup abc.xyz
> Server:         192.168.0.3
> Address:        192.168.0.3#53
>
> Name:   abc.xyz
> Address: 192.168.0.3
> Name:   abc.xyz
> Address: 192.168.0.1
> Name:   abc.xyz
> Address: 192.168.0.2
> #
>
> Again, where this is handy is when configuring sssd.conf for example 
> or other apps for that matter.  I can just point the app to 
> authenticate against the domain and I have my redundancy solved.  
> Windows Server 2012 does it, but FreeIPA didn't, so I threw the 
> question out there.

IPA uses SRV records heavily, all IPA related services have SRV records, 
SSSD uses SRV records of IPA, client should use SRV record to connect to 
the right service (or URI record - will be in next IPA). SRV records 
work for IPA locations mechanism, we cannot achieve this with pure A 
records.

>
> Delegation from this Windows DNS works as expected.  Any lookup from 
> dom.abc.xyz is forwarded too and handled by FreeIPA servers. Tested 
> this out. No issue with this.
>
> I did see earlier that there is no A record for dom.abc.xyz in 
> FreeIPA. My reasons for asking if there was an IP on the subdomain in 
> FreeIPA were above but the missing IP on the subdomain isn't a major 
> issue for me.  Things are working without dom.abc.xyz resolving to an 
> IP.  What I was hoping for is to have a VIP for the IPA servers and 
> one for the Windows Server 2012 DNS Cluster in /etc/resolv.conf.  (I 
> have the VIP for the windows server).  One forwarding to the other for 
> a given domain.  This is all for testing a) redundancy, b) forwarding, 
> a) authentication .
>
> IE:
>
> # cat /etc/resolv.conf
> search nix.mds.xyz mds.xyz
> nameserver 192.168.0.3            <------------ Win Cluster DNS VIP
> nameserver 192.168.0.4            <------------ IPA Cluster DNS VIP
>
> * Just what I want to achieve above.  VIP 192.168.0.4 doesn't exist on 
> my cluster yet.  I'm looking to integrate ucarp with the above IPA 
> servers.
>
>
> 2) More to the topic of my second question however, is that 
> /etc/resolv.conf, on the IPA servers themselves, get's rewritten on 
> restart.  Would like to know by what if I already uninstalled 
> NetworkManager?  When I configured the FreeIPA server, I used:
>
> ipa-server-install --setup-dns --forwarder=192.168.0.3 -p "Hush!" -a 
> "Hush!" -r DOM.ABC.XYZ -n dom.abc.xyz --hostname ipa01.dom.abc.xyz
>
> Notice I used the VIP of the Windows Server 2012 Cluster when 
> installing FreeIPA.  This is nice for redundancy.  So the resolv.conf 
> ends up being:
>
> # cat /etc/resolv.conf
> # Generated by NetworkManager
> search abc.xyz
> nameserver 192.168.0.3
> nameserver 123.123.123.1
> nameserver 123.123.123.2
>
> Then I add:
>
> search dom.abc.xyz abc.xyz
>
> but it changes back to search abc.xyz (the Windows Server 2012 DNS). 
> This all works, except for the above minor items, and I can resolve 
> anything over this network.  (  Thinking this is fine because the 
> forward is on the subdomain.  I haven't had issues with forwarding 
> through this setup.  )
>
> # cat /etc/resolv.conf
> # Generated by NetworkManager
> search abc.xyz
> nameserver 192.168.0.3
> nameserver 123.123.123.1
> nameserver 123.123.123.2
>
> But NetworkManager is not installed on these IPA servers.  I've 
> removed it earlier:
>
> # rpm -aq|grep -i NetworkManager
> #
>
> Is FreeIPA replacing /etc/resolv.conf with a copy it keeps elsewhere?

On servers with DNS /etc/resolv.conf should point to 127.0.0.1 and ::1, 
and global or per server dns forwarders should be configured instead

Have you properly stopped NetworkManager using systemctl stop and 
systemctl disable ? In case you just removed rpm files service can still 
work.
I recommend to update network manager config, not to remove it :)

As last resort way, you can set immutable bit to resolv.conf if 
something is still changing your resolv.conf file

>
> 3) After running:
>
> ipa-client-install --mkhomedir --enable-dns-updates
>
> on a new host, the hostname of the new host doesn't resolve for a few 
> minutes.  How do I make this instantaneous?  (Other then that, 
> autodiscovery of the IPA servers is excellent!).  Before installing 
> the IPA Client, the new hosts /etc/resolv.conf file looks like this:
>
> # cat /etc/resolv.conf
> search abc.xyz
> nameserver 192.168.0.3
> nameserver 123.123.123.1
> nameserver 123.123.123.2
>
> I did dig, host, nslookup earlier.  Verified all except for the items 
> I'm inquiring about.
>

That weird, because ipa-client-install creates A records directly to DNS 
server using nsupdate, so it should be accessible instantly. Do you have 
any caching DNS servers?

Martin