The local DNS server calls itself Unknown

Software SW help
1

Hi there,

at first sorry for my bad english and the following dump question :smiley: I searched the config, forums and google but didnt find something helpfull.

I have the Turris Omnia 2019 behind a Cable Modem. All Clients are connectet with the Omnia.

The clients get the omnia as DNS Server with the IPv4 and IPv6 Adress. There is no Problem with the resolver.

But when i make a lookup the Omnia show himself als Unknown

C:\Users\InsertRandomNameHere>nslookup
Standardserver:  UnKnown
Address:  fdb4:c82:8346::1

How could i manage that the Omnia call itself something other then UnKnown.

The Hostname in Config is changed

config system
        option hostname 'Turris_Omnia'

Thanks a lot

2

Do you have reverse DNS lookup enabled on the client?

3

I believe the reverse lookup does not work out of the box and must be enabled using following:

This will allow to resolve hostnames of the computer in the lan domain. Unfortunately the router is unable to resolve its own hostname.

@vcunat can you shed some light on this please?

4

Doesnt know how to check this. I have to configer this on the client or the router?

But if i connect with my Notebook to our VPN and get the Company DNS i get a resolved name

C:\Users\InsertRandomNameHere>nslookup google.de
Server:  core-dc5.company-dns.tld
Address:  xxx.xx.xx.xx

if i make a lookup without VPN i also get thes

C:\Users\InsertRandomNameHere>nslookup
Standardserver:  UnKnown
Address:  fdb4:c82:8346::1
5

The company sets its own DNS server through the VPN and bypasses the local DNS instance on the TO.

It is 2-fold:

  • a PTR record on the TO which maps the TO ip to a local domain name, trust dnsmasq can provide such which then the local resolver kresd can look up. Alternatively it might be possible to create a PTR record from within the kresd configuration but I am not familiar with kresd
  • the client connecting to the TO would have to perform a reverse lookup. Since that works apparently over the VPN it would seem to be ok
6

You can explicitly add any name-address bindings on Turris and the corresponding reverse records will also be answered likewise. https://wiki.turris.cz/doc/en/public/dns_knot_misc#adding_static_address_records

But I have no idea how to “nicely” add all the addresses like fdb4:c82:8346::1 in case they might change over time (or when reconfigured), and honestly I can’t see what it’s good for in this case (except for nicer nslookup output).

7

Hi there,
thanks for all your fast answers.

But I have no idea how to “nicely” add all the addresses like fdb4:c82:8346::1 in case they might change over time (or when reconfigured), and honestly I can’t see what it’s good for in this case (except for nicer nslookup output).

At first i wanted to check if there is any bad configuration. Then there was this little voice calling “There have to be some way to do this”

You can explicitly add any name-address bindings on Turris and the corresponding reverse records will also be answered likewise.

I tryed to add the specific part in the config. At first with a separate hosts file and then with the original hosts file. But both times with no change.
If i check the “Enable DHCP clients in DNS” in Foris Interface from the Omnia when adding “.lan”, then i could lookup the ip from the Box, but the UnKnown is still there

C:\Users\InsertRandomNameHere>nslookup turris_omnia.lan
Server: UnKnown
Address: fdb4:c82:8346::1

Nicht autorisierende Antwort:
Name:    turris_omnia.lan
Address:  10.0.0.1


C:\Users\InsertRandomNameHere>nslookup turris_omnia.lan 10.0.0.1
Server:  UnKnown
Address:  10.0.0.1

Nicht autorisierende Antwort:
Name:    turris_omnia.lan
Address:  10.0.0.1

Add all if there is no missconfiguration on my side and the “ugly” UnKnown Name is normal. Then i can handle my inner Monk :slight_smile:

Thanks again and all have a nice and Corona Free Week :mask:

8

I think you’d need an line like

 fdb4:c82:8346::1 turris_omnia

in the configured hosts file to get the reverse translation for that name.