Use DNS servers just from one uplink or add priority

[norg]

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

[Lumpy]

If I'm correct you are a Telekom Deutschland customer? If that's the case you don't need their DNS servers (or do you use SIP-Trunk etc.?) at all. I'm currently using a SVDSL connection from Telekom and I've configured the Cloudflare DNS servers as the only DNS without provider override.

IIRC all you need is to configure your VoIP settings with a real username and a password. I think it's called "MyLogin" in the Telekom customer center.

€dit: You have to disable the automatic login for your VDSL connection, but I think that's the case already. What device do you use as modem for the VDSL connection?

After disabling the automatic login, you can't use "anonymous@t-online.de" for VoIP anymore. You have to specify your login credentials in your VoIP device and you are good to go. I'll take a look at my configuration when I'm back home.

Bottom line is, I can't think of a scenario where Telekom DNS servers are manadtory for VoIP...

[norg]

Yes I am Telekom Business, but I need correct replies for tel.t-online.de which change from time to time. If you use any other servers you end up with 217.0.128.133 which is not correct for all usecases.
I got this information from a Telekom technician who helped me debug some outage with my telephone. And this was the reason.

[Lumpy]

I'm not sure how to achieve this without any known DNS entries from Telekom. But you are a business customer, shouldn't they tell you which DNS servers to use? I'm pretty sure that we received a list of at least three nameservers for our CompanyConnect line at work. Have you asked Telekom business support about that? Maybe "Telekom hilft!" social media team can get you the information that is needed in this case...

Other than that I'm a bit at a loss now.

[norg]

It's not a company connect contract. So the DNS servers might change from time to time and I receive them via PPPoE. But that would be another workaround, yes.

I think it's still a valid setup to have the option to define the override DNS not global but on the interfaces.

[Lumpy]

That is one of the many reasons we canceled all our landline telephony contracts with Telekom. Internet connection, great, this works just fine and stable as expected. But after the shutdown of ISDN we decided to switch our telephony away from Telekom. So far, we don't regret the decision at all.

I'm still convinced that Telekom isn't able to provide VoIP 100% standard compliant to its customers... Or they make it at least really complicated to use ones own hardware. I've gained experience with Sipgate, Easybell, Telekom, 1&1, QSC over the years and none of the others was as complicated or error-prone as Telekom.

This doesn't help you at all but maybe you should think about changing your telephony provider in the future.