VOIP / Go-Box-100 issue with NextDNS ( stun.t-online.de)

Hi all,

I am running a Gigabit Go-Box-100 for VOIP communication.

This device connects to my VOIP provider (Deutsche Telekom) using tel.t-online.de & tel.t-online.de

This was working for months until I discovered a failed connection today.

Only changing the DNS servers from NextDNS to public DNS (Google & Cloudflare) fixed it finally.

No blocked lookups of servers appeared in the NextDNS protocol, so I really don't know why the connection is no longer working when I use NextDNS.

- Donald24
- 11 mths ago
- Reported - view
I can copy this behavior also with a FRITZ!box using T-Com VoIP. It loses it phone number registrations after several hours and the FB log shows a DNS error. No blocks in NextDNS logs. I also had to switch back to other dns. I gave up troubleshooting, reckoning its very provider specific nature.
- MirkoKas
- 10 mths ago
- Reported - view
Just to help some others. I experience the same thing with a Fritzbox 7490.

As I simply use this box for VoIP service I just gave it a different DNS server in the LAN configuration within the box. Now it works.

A fix though would be really nice!
- Donald24
- 10 mths ago
- Reported - view
Exactly, I did it the same way. I found out, that it is the EDNS-client (enabled) subnet setting, that cripples the DNS request for the VOIP services. If you want, you can use a different configuration on NextDNS, and link the IPv4 of your DSL to it, and use the IPv4 servers from the config page in your Fritzbox. But anyway, I do not think, that it's worth the hustle.... Just take official DNS server for your VOIP services, there are no malicious or advertisment calls from it anyway....
- Mike_Brust
- 9 mths ago
- Reported - view
I just faced another failed connection with my VOIP provider, it was stable for quite a while.

Changing to a different (non-NextDNS) DNS provider fixed it immediately.

Content aside