DNS cache cannot resolve address periodically

RouterOS General
1

Hello all.
I’m haveing issue with DNS in Microtik hap ac2 with latest soft version (6.46.4). Most of the time all works ok but from time to time the DNS is not resolving names. I’ve checked that:

  • cache is not full
  • to be on the safe side I do automatic flush once a day
  • the parent dns servers are available and responding (Google DNSes)
  • the address is not in the cache

Sometimes manual flush helps but sometimes i need to reboot router.
Do you have an idea why this can happen or where I should look for ?

This is small network so its not due to high traffic.

2

It looks like good case for packet sniffer. Capture DNS queries from client to router and see if there are some responses. Check what’s in cache. Also capture requests from router to upstream resolvers and you’ll see what the router is sending and what it gets back. Or doesn’t.