Mikrotik DNS Stop working...

RouterOS General
1

Hello! I have some problem…
In one time DNS server on Mikrotik - stopped working…

 /ip dns print 
                servers: 8.8.8.8
        dynamic-servers: 
  allow-remote-requests: yes
    max-udp-packet-size: 4096
   query-server-timeout: 2s
    query-total-timeout: 10s
             cache-size: 2048KiB
          cache-max-ttl: 1w
             cache-used: 11KiB

I enabled logging DNS and when i do “nslookup google.com 10.2.0.1” on windows, Mikrotik echo:

echo: dns,packet --- got query from 10.2.10.5:55427:
echo: dns,packet id:1 rd:1 tc:0 aa:0 qr:0 ra:0 QUERY 'no error'
echo: dns,packet question: 1.0.2.10.in-addr.arpa:PTR:IN
echo: dns query from 10.2.10.5: #4 1.0.2.10.in-addr.arpa. PTR
echo: dns,packet --- sending udp query to 8.8.8.8:53:
echo: dns,packet id:6c5b rd:1 tc:0 aa:0 qr:0 ra:0 QUERY 'no error'
echo: dns,packet question: 1.0.2.10.in-addr.arpa:PTR:IN
echo: dns,packet --- sending udp query to 8.8.8.8:53:
echo: dns,packet id:34f5 rd:1 tc:0 aa:0 qr:0 ra:0 QUERY 'no error'
echo: dns,packet question: 1.0.2.10.in-addr.arpa:PTR:IN
echo: dns,packet --- sending udp query to 8.8.8.8:53:
echo: dns,packet id:2200 rd:1 tc:0 aa:0 qr:0 ra:0 QUERY 'no error'
echo: dns,packet question: 1.0.2.10.in-addr.arpa:PTR:IN
echo: dns,packet --- sending udp query to 8.8.8.8:53:
echo: dns,packet id:4fb0 rd:1 tc:0 aa:0 qr:0 ra:0 QUERY 'no error'
echo: dns,packet question: 1.0.2.10.in-addr.arpa:PTR:IN
echo: dns,packet --- sending udp query to 8.8.8.8:53:
echo: dns,packet id:4732 rd:1 tc:0 aa:0 qr:0 ra:0 QUERY 'no error'
echo: dns,packet question: 1.0.2.10.in-addr.arpa:PTR:IN
echo: dns done query: #4 dns server failure
echo: dns,packet --- sending reply to 10.2.10.5:55427:
echo: dns,packet id:1 rd:1 tc:0 aa:0 qr:1 ra:1 QUERY 'server failure'
echo: dns,packet question: 1.0.2.10.in-addr.arpa:PTR:IN

All works fine before one moment…
Whats wrong? (“nslookup ya.ru 8.8.8.8” is working on Windows PC, Mikrotik reboot not helping…)

2

Hi, I had the same problem, I run a packet sniffer of the DNS request going from the Mikrotik to the external DNS server, and discovered it was using the wrong source address. I think it was using 192.168.x.x this router did not have nat enabled.
To resolve I set the DNS to the ISP DNS server, which was in the same subnet as the WAN IP so the TIK had to use the correct source IP.

There are other posts on this forum for DNS issues, I would search for them, the first thing to do is to get you TIK to be able to resolve its own DNS lookups.

W