Add PTR and NS Records to DNS Resolver possible?

kolpinkb

Thanks for the clarification johnpoz. Rookie mistake on my part. I have all the records required for Android and two green check marks but I still can't seem to get the mobility app to find my printers.

johnpoz

I have gotten a bit side tracked.. I will try and find some time here tmrw morning to bring up the mobility on box on one of my wifi segments with printer and papercut ng on different segment to get this working.. And will turn off the functionality on the printer directly, etc.

Per this
"Support Android and Chromebook, then you are right. They only need to put the rpc.pc-printer-discovery.domain.tld using host override feature of Unbound as you said and it should work."

All you should need is the override pointing to the IP of your box running the mobility.. As long as the mobility has your printer(s) setup, etc.

kolpinkb

I did exactly that.

However, I'm not sure if the following makes a difference.

-papercut and mobility print are on the same machine
-printrr is on same subnet as above
-android phone is on a different subnet

mobility_dev

Hi thehammer86,
Can you access the URL http://rpc.pc-printer-discovery:9163/printers from a browser on your Android device?
It should return to you some JSON if you have some printers on your Mobility Print server.

kolpinkb

It returns JSON if I add .example.com.

I must be missing something in my unbound config?

mobility_dev

What is the search domain (DNS suffix) on your Android device?

kolpinkb

I don't seem to have that option available in my wifi. Running Android 6.0.1.

I have my search domain set in my DHCP server on pfSense.

I've also manually added it to my windows PCs. For the windows PCs I know the search domain is working because I don't have to add the example.xom part when I do an NS lookup.

Selo

Hello everybody,

I was wondering: was this issue solved in the end?
We are facing the same problem configuring Resolver with the Mobility records.
Checking the records using the Mobility application, we keep getting errors on the PTR records (the other 2 are working fine).
Screenshot of working DNS entries would be really great!

kolpinkb

Not yet with the Unbound resolver. I ended up setting up a separate sever just for bind9. I have everything working with that setup.

Selo

Is it possible to post the actual records you used (as an example/syntax)?
Screenshot of dns settings?
thanks!

johnpoz

And what did you setup exactly – that has been the whole question... See you can for sure setup PTR records on unbound...

The person from Mobility print was suppose to be answering those questions.. Which I do not recall ever got answered.

Selo

I can tell this:

we are working on this issue with 2 experienced engineers. We have setup the 4 records as requested by the mobility print software.
nslookup confirms the 4 records are active and correct. After checking the records with the mobility software, we keep getting an error on the PTR records.
Fortunately we have an active Papercut license (it is a new install with 150 users), we created a support ticket…hope to get quick response.
If anyone has fixed this PTR issue, I would really like to see the DNS entries...
We also suggested a change to the mobility print client: a possibility to enter an ip-address instead of using the autodiscover option...

kolpinkb

Posting my named.conf file shortly for bind. Just obfuscating the IPs and domains.

Also, tech support was kind enough a few weeks ago to spend 2-3 hours on the phone with me to try an figure out the problem with unbound. I found something in Mobility Print's log files that may be of use.

Hold tight.

johnpoz

From what I recall the client was not looking for what they said to create on their website.. But I can till you for fact is that unbound can create PTR records…

Here is simple PTR query for IP on unbound... Answers just fine...


> dig -x 192.168.9.8

; <<>> DiG 9.11.2 <<>> -x 192.168.9.8
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 37198
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;8.9.168.192.in-addr.arpa.      IN      PTR

;; ANSWER SECTION:
8.9.168.192.in-addr.arpa. 1635  IN      PTR     Storage.local.lan.

;; Query time: 9 msec
;; SERVER: 192.168.3.10#53(192.168.3.10)
;; WHEN: Tue Jan 16 11:31:45 Central Standard Time 2018
;; MSG SIZE  rcvd: 84

What exactly is going to be queried and what should be the answer and we can validate whatever that something is can be entered into unbound. But 100% for sure unbound can answer for a PTR query.

Selo

OK, let´s wait for the named.conf file thehammer86 was going to post…
Also curious about this: "I found something in Mobility Print's log files that may be of use."

johnpoz

I played with this for a bit - I could never get the client to actually do a ptr query like they said it should.. Their docs from what I remember are not very clear. My trial ran out and attempted to run the mobility client on the same box the server was run on.

I could try to setup it up again on some other machines - But once we know what actual query be it PTR or some other we can work out how to setup (if possible) for unbound to respond. What I can tell you for 100% fact is the unbound can respond with a PTR… And NS records, so there is something missing in the puzzle here.

kolpinkb

Here's the relevent config from a bare-metal machine I installed bind9 on. Please make sure the domain and search list your dhcp server is handing out matches your domain for the mobility print entries. Three different files below:
/etc/bind/named.conf

options {
directory "/etc/bind";
pid-file "/var/run/bind/run/named.pid /var/run/named.pid /var/run/named/named.pid /var/run/bind/run/named/named.pid";
forwarders {
208.67.220.220;
208.67.222.222;
2620:0:ccd::2;
2620:0:ccc::2;
};
forward first;
allow-query {
192.168.0.0/16;
};
};

zone "." {
type hint;
file "/etc/bind/db.cache";
};

zone "168.192.in-addr.arpa" {
type master;
file "/var/lib/bind/192.168.rev";
};
key rndc-key {
algorithm hmac-md5;
secret "XXXXXXXXXXXXXXXXXXXXXX==";
};
controls {
inet 127.0.0.1 port 953 allow { 127.0.0.1; } keys { rndc-key; };
};
zone "example.com" {
type master;
file "/var/lib/bind/example.com.hosts";
};

/var/lib/bind/192.168.rev

168.192.in-addr.arpa. IN SOA cloud1.example.com. admin.example.com. (
1513635071
10800
3600
604800
38400 )
168.192.in-addr.arpa. IN NS cloud1.example.com.
3.71.168.192.in-addr.arpa. IN PTR cloud5.example.com.

/var/lib/bind/example.com.hosts

$ttl 38400
example.com. IN SOA cloud1.example.com. admin.example.com. (
1513706509
10800
3600
604800
38400 )
example.com. IN NS cloud1.example.com.
cloud5.example.com. IN A 192.168.71.3
cloud1.example.com. IN A 192.168.71.4
pc-printer-discovery.example.com. IN NS cloud5.example.com.
b._dns-sd._udp.example.com. IN PTR pc-printer-discovery.example.com.
lb._dns-sd._udp.example.com. IN PTR pc-printer-discovery.example.com.

johnpoz

Problem with that config is that your SOA for example.com is cloud1.example.com

But I take it cloud5 is the mobility server but its a example.com domain ns, so do cloud1 and cloud5 the NS for example.com have the same records?

What does pc-printer-discovery.example.com. actually resolve too? Since from your config I should be able to answer either cloud1 the SOA for example.com or cloud5 for this A record.

kolpinkb

Both PaperCutNG and the MobilityPrint Server are on the same machine (cloud5). I can't seem to track down the log entry from MobilityPrint but its starting to come back to me now. Something about the log error hinted at a permission issue with Unbound. Because Unbound is set up as an authoritative name server for example.com, it didn't like cloud5.example.com being an authoritative name server for the subdomain pc-printer-discovery.example.com.

Does that help?

I coundn't get any further with unbound so that's why I ditched it and went to bind.

johnpoz

and when you do a query for pc-printer-discovery.example.com, is this a A record query TXT, SRV what?

Seems pretty pointless to set it up that way.. Why could you not just setup pc-printer-discovery.example.com to be resolved by unbound directly? Be it A record or TXT or SRV, etc. Seems stupid to do it that way.. I see no point to it.

Actually goes against dns practice to delegate like that. Why sure pc-printer-discovery.example.com could be sub domain and delegated to a different NS. you would then look fror something like host.pc-printer-discovery.example.com in the subdomain.

Unbound is not actually meant to be an authoritative NS.. So that is prob why there are some issues - but you could for sure just put in the entry for pc-printer-discovery.example.com directly in unbound so it could resolve it without having to delegate that to cloud5..

Unbound is a validating, recursive, and caching DNS resolver. It is not actually meant to be an authoritative NS… While it can answer specific records, from a local database - it has issues with cnames as well, etc. Since its not actual designed to be an authoritative NS.

But if the client wants to do a PTR query and then a query for that fqdn that is returned it for sure could answer a A, TXT, SRV record etc... for the actual fqdn that gets queried.