Use DNS servers just from one uplink or add priority

[norg]

I updated to 19.7 and so far everything quite nice, thanks. But this issue is still the same for me, so quoting myself from (https://forum.opnsense.org/index.php?topic=13374.0):

Hi,

I have two uplinks, one via PPPoE (VDSL) and one via DHCP (Cable). The issue is that I just want to use the DNS servers provided by the VDSL uplink since those are the only ones which have the correct DNS entries for VoIP. The option Allow DNS server list to be overridden by DHCP/PPP on WAN is global and thus I end up with a mixed resolv.conf. This results in VoIP issues.
I also don't want to hardcode the DNS servers for VDSL as they could change.
Is there a way to handle this, at least somewhere if not in the Web UI?
Or any other solution to solve this.

Thanks

So any hints how to solve/fix/patch it myself are welcome :)

[Maurice]

I'm not aware of an interface-specific option for this. If you really need it you could create a feature request on GitHub.

At the moment your best option is configuring the DNS servers manually. Most ISPs don't change them very often. You mentioned Deutsche Telekom. Their current DNS resolver addresses have been in use since at least 2014.

Cheers

Maurice

[mimugmail]

Maybe ... MAYBE .. you can add some options to dhcp config in your second WAN to not accept the DNS records.
But I have no idea how and if this works, I only know there's an advanced section :)

[StP]

I'm in the same boat now.
Telekom switched us from ISDN to SIP-Trunk last Monday.
Fons are dead since then :(
DSL connection works, I have internet access.
Problem is DNS resolution of Telekom's Outbound Proxy and SIP Registrar.
reg.sip-trunk.telekom.de and sip-trunk.telekom.de are unknown.
I let the PPP override the OPNsense DNS-Servers on login.
"Allow DNS server list to be overridden by DHCP/PPP on WAN"
That doesn't help. Even with no DNS-Server configured in OPNsense internet access works but it cannot resolve the two SIP related hosts. So OPNsense seems to have received a DNS-Server on PPP connect.

Does anyone have a "working" DNS server address for this setup?

Regards
  Stefan

[Maurice]

I'm in the same boat now.

I don't think so. This thread is about a specific issue with dual WAN and two different ISPs.

It seems you simply misconfigured your PBX. reg.sip-trunk.telekom.de and sip-trunk.telekom.de don't have A records, that's by design. Please check their documentation about NAPTR and SRV records, that's off topic here.

Cheers

Maurice

[StP]

Maurice,
you are right, sorry.

Stefan

[norg]

At the moment your best option is configuring the DNS servers manually. Most ISPs don't change them very often. You mentioned Deutsche Telekom. Their current DNS resolver addresses have been in use since at least 2014.

I looked into that and they change from time to time when I look into what I receive via PPPoE, they even document this fact:

https://www.telekom.de/hilfe/festnetz-internet-tv/e-mail/e-mail-server-e-mail-protokolle-und-e-mail-einrichtung/wichtige-server-der-telekom?samChecked=true (see DNS section, german language though)