$HOSTNAME.lan in forward and reverse DNS

[Zugschlus]

Hi,

when I query the DNS service of the RUTX08 reverse for its IP address¹ it returns a (synthesized?) PTR record for its hostname with .lan as the domain².

We have reverse DNS, it works and has the truth we want to be the truth, and the RUTX08 has information about how to reach those DNS servers that know about the name we want to be there.

How can I turn off this automatism?

Greetings, Marc Haber

¹ that would be like dig @192.168.1.1 1.1.168.192.in-addr.arpa PTR

² for example marcstestrouter.lan

[Matas]

Hi, Marc,

Could you possibly provide some screenshots of the output? I can’t seem to reproduce the same thing as you’ve described.

Regards,
M.

[Zugschlus]

Sure. This is what I have configured:

The device has the address 172.22.11.1 on its br-lan interface. The following shell transcript is from a machine connected to br-lan:

# dig @172.22.11.1 1.11.22.172.in-addr.arpa PTR

; <<>> DiG 9.18.41-1~deb12u1-Debian <<>> @172.22.11.1 1.11.22.172.in-addr.arpa PTR
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 9636
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
;; QUESTION SECTION:
;1.11.22.172.in-addr.arpa.      IN      PTR

;; ANSWER SECTION:
1.11.22.172.in-addr.arpa. 0     IN      PTR     teltonikahost.lan.

;; Query time: 0 msec
;; SERVER: 172.22.11.1#53(172.22.11.1) (UDP)
;; WHEN: Wed Dec 03 22:47:15 CET 2025
;; MSG SIZE  rcvd: 84

# dig @192.168.2.42 1.11.22.172.in-addr.arpa PTR

; <<>> DiG 9.18.41-1~deb12u1-Debian <<>> @192.168.2.42 1.11.22.172.in-addr.arpa PTR
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 64547
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 3

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

;; ANSWER SECTION:
1.11.22.172.in-addr.arpa. 600   IN      PTR     vpn-somewhere.example.com.

;; AUTHORITY SECTION:
22.172.in-addr.arpa.    600     IN      NS      dns001.example.com.
22.172.in-addr.arpa.    600     IN      NS      dns002.example.com.

;; ADDITIONAL SECTION:
dns001.example.com.       600     IN      A       192.168.2.44
dns002.example.com.       600     IN      A       192.168.2.42

;; Query time: 36 msec
;; SERVER: 192.168.2.42#53(192.168.2.42) (UDP)
;; WHEN: Wed Dec 03 22:47:29 CET 2025
;; MSG SIZE  rcvd: 164

#

I would expect your device to follow its configuration and forward the request for PTR-Record of 1.11.22.172.in-addr.arpa to 192.168.2.42 and 192.168.2.44 and to deliver whatever those forwarders did return.

Greetings, Marc Haber

[Matas]

Hi there,

Just to inform you, I’ve reached out to our R&D to ask whether it’s possible to have this disabled.

Regards,
M.

[Matas]

Hi, @Zugschlus !

Apologies for the long wait, I got an answer from the R&D with some suggestions, here they are:

1. Try disabling the Filter Private option:
   
   
   
   After doing so, please check your dnsmasq config file for the bogus-priv option, if possible, provide a screenshot or a copy-pasted log.
2. Check /etc/hosts/ and make sure there is no LAN IP stored of your device.
3. You can also try disabling the Localise Queries option.

Some more information can be found here

Regards,
M.