HI All,
I have really annoying and frustrating problem.
My router:
routerboard: yes
board-name: hAP ac^3
model: RBD53iG-5HacD2HnD
serial-number: F3**********54
firmware-type: ipq4000
factory-firmware: 6.47.10
current-firmware: 7.19.1
upgrade-firmware: 7.19.1
DNS Settings:
[admin@MikroTikAc3] /ip/dns> print
servers: 1.1.1.1
8.8.8.8
8.8.4.4
dynamic-servers:
use-doh-server:
verify-doh-cert: no
doh-max-server-connections: 5
doh-max-concurrent-queries: 50
doh-timeout: 5s
allow-remote-requests: yes
max-udp-packet-size: 4096
query-server-timeout: 2s
query-total-timeout: 10s
max-concurrent-queries: 100
max-concurrent-tcp-sessions: 20
cache-size: 2048KiB
cache-max-ttl: 5m
address-list-extra-time: 0s
vrf: main
mdns-repeat-ifaces:
cache-used: 72KiB
I have a BIND9 DNS server on the internet.
And I have a dynamic zone, means that the zone update by nsupdate. This is a kind of dynamic DNS service.
But my host cannot be resolved via my Mikrotik router:
It works with public (Google) DNS service:
dig @8.8.8.8 test.dyn.vincze.work
; <<>> DiG 9.18.33-1~deb12u2-Debian <<>> @8.8.8.8 test.dyn.vincze.work
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 65399
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;test.dyn.vincze.work. IN A
;; ANSWER SECTION:
test.dyn.vincze.work. 60 IN A 192.168.0.10
;; Query time: 39 msec
;; SERVER: 8.8.8.8#53(8.8.8.8) (UDP)
;; WHEN: Wed Jun 18 13:47:16 CEST 2025
;; MSG SIZE rcvd: 65
Hint: I know that the “192.168.0.10” IP address is private, but the situation is the same with public IP addresses.
But using my Mikrotik rotuer’s IP address:
dig @172.16.0.1 test.dyn.vincze.work
; <<>> DiG 9.18.33-1~deb12u2-Debian <<>> @172.16.0.1 test.dyn.vincze.work
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 46904
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0
;; QUESTION SECTION:
;test.dyn.vincze.work. IN A
;; Query time: 75 msec
;; SERVER: 172.16.0.1#53(172.16.0.1) (UDP)
;; WHEN: Wed Jun 18 13:48:24 CEST 2025
;; MSG SIZE rcvd: 38
This is my SOA record:
dig @8.8.8.8 test.dyn.vincze.work -t SOA
; <<>> DiG 9.18.33-1~deb12u2-Debian <<>> @8.8.8.8 test.dyn.vincze.work -t SOA
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 50990
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;test.dyn.vincze.work. IN SOA
;; AUTHORITY SECTION:
dyn.vincze.work. 600 IN SOA dyn.vincze.work. jvincze84.gmail.com. 2025061749 28800 7200 604800 600
;; Query time: 35 msec
;; SERVER: 8.8.8.8#53(8.8.8.8) (UDP)
;; WHEN: Wed Jun 18 13:50:00 CEST 2025
;; MSG SIZE rcvd: 104
I’ve tried to flush dns, restart the router but did not helped.
Here comes my struggle.
Sometimes it works fine (usually after flush dns, and wait one or two minutes):
First query (see the timestamp) working: (NOERROR)
date && dig @172.16.0.1 mikrotik-gomba.dyn.vincze.work
Wed Jun 18 01:55:15 PM CEST 2025
; <<>> DiG 9.18.33-1~deb12u2-Debian <<>> @172.16.0.1 mikrotik-gomba.dyn.vincze.work
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 8024
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0
;; QUESTION SECTION:
;mikrotik-gomba.dyn.vincze.work. IN A
;; ANSWER SECTION:
mikrotik-gomba.dyn.vincze.work. 8 IN A 91.120.111.242
;; Query time: 0 msec
;; SERVER: 172.16.0.1#53(172.16.0.1) (UDP)
;; WHEN: Wed Jun 18 13:55:15 CEST 2025
;; MSG SIZE rcvd: 64
But after less than a minute (NXDOMAIN):
date && dig @172.16.0.1 mikrotik-gomba.dyn.vincze.work
Wed Jun 18 01:55:32 PM CEST 2025
; <<>> DiG 9.18.33-1~deb12u2-Debian <<>> @172.16.0.1 mikrotik-gomba.dyn.vincze.work
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 10041
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0
;; QUESTION SECTION:
;mikrotik-gomba.dyn.vincze.work. IN A
;; Query time: 47 msec
;; SERVER: 172.16.0.1#53(172.16.0.1) (UDP)
;; WHEN: Wed Jun 18 13:55:32 CEST 2025
;; MSG SIZE rcvd: 48
I don’t have to say that I did not modify anything between the two request. 
I don’t understand what’s happening. 
Every help would be appreciated.
Br,
Janos Vincze