VoIP call interruptions and invalid records in DNS cache after upgrading to long-term version 6.47.9 or 6.47.10.

RouterOS Beginner Basics
1

Hi!

After upgrading from long-term version 6.46.8 to 6.47.9 or 6.47.10 VoIP calls started to hang up after 1-2 minutes.

In DNS cache are invalid, negative records of proxy servers, type unknown, data 0.0.0.0, like:
proxy1a.elio”œļŌ
proxy1a.elio”œļt
proxy1a.elio”œÓt
proxy1b.elio”œÓt

the correct entries are:

proxy1a.elion.ee A 217.159.187.4
proxy1b.elion.ee A 217.159.187.132

After downgrading to version 6.46.8 all works as expected, all entries in DNS cache are OK.

Which could be a problem? Router is RB4011iGS+, VoIP device Cisco IP phone 303, Cisco is directly connected to router, no other devices.
SIP helper is disabled, Fast path is allowed, neighbor discovery is enabled.

Thanks in advance

2

When you have DNS cache problems, make sure you turn off DoH.

3

Hi!

DoH is off:

servers: aaa.bbb.ccc.ddd,eee.fff.ggg.hhh
dynamic-servers:
use-doh-server:
verify-doh-cert: no
allow-remote-requests: yes
max-udp-packet-size: 4096
query-server-timeout: 2s
query-total-timeout: 10s
max-concurrent-queries: 1000
max-concurrent-tcp-sessions: 20
cache-size: 4096KiB
cache-max-ttl: 1w
cache-used: 37KiB