Hi,

thanks for your Answer.

But I mean the Settings for DNS Advertisement on IPv6 on my local Network.

IPv6 from my Local Provider is enabled and working.

In IPv4-Settings for Local Network I can configure a different DNS-Server, which is used by the Router and would be advertised on LAN by DHCP.

(Settings on IPv4 contains Primary DNS)

(IPv6-Settings for DHCPv6 - DNS-Settings missing)

I use an own DNS-Server on my LAN, which can't be used anymore if IPv6 ist activated because the Router advertises itself as Prmary IPv6-DNS-Server.

I don't understand, why I can set the DNS in IPv4, but not on IPv6 :/

  @Joseph-TP 

I have the same problem with VX800v. I simply cannot set a custom DNS for IPv6. 
And it is really not an ISP issue. It is that the current router firmware simply doesn't support that.
I always get the ISP's standard gateway as DNS server.
And that means, VX800v is not a fully Dual-Stack router, no matter what product sheets or advertising are saying.

I've tried to setup an own DHCPv6 server, but that doesn't work too.
Clients always get the routers standard gateway DNS, even when using RADVD without activating RDNSS.
 

I ask you to add this feature in near future, since otherwise VX800v is not recommended for those who want fine grain control of IPv6 management in their home networks.

  @Joseph-TP 

Joseph-TP wrote

Hi@Martin-B ,

 

Is this a modem provided by your ISP? 

No, it is the standard model, that I've purchased in local electronics store.

I have found a possible solution by providing an own RADVD in my home network (RPi) and it advertises my IPv6 DNS.
But nevertheless, the ISP or router always and ever advertises its IPv6 DNS, even when disabling RDNSS. Hence I have to set that in my client devices individually.
 

At the moment I have IPV6 LAN disabled at the router to have no DNS leaks at all.

  @Martin-B 

Hi,

a few days ago, I found a solution that works well.

Even when "IPv6 LAN" is disabled, the router always provides a local IPv6 address via "fe80::".
(You can find this IP on "Extendes Settings -> Overview -> IPv6-Standardgateway")



If you use this IPv6 address and, for example, use "PiHole" as the DNS server on the network, you can use RADVD in PiHole, provided the gateway of the computer running PiHole is set to this "fe80" IP address and the computer itself has IPv6 addresses.

In Pihole, this Values needs to be filled:


If IPv4 and IPv6 is filled and an "fe80"-IP is included, set (Settings -> DHCP):


Using the built-in RADVD function, Pi-hole provides its own IPv4 and IPv6 addresses to the clients as primary DNS server.

Therefore, an active "IPv6 LAN" on the router is no longer necessary.

Since then, I have a significantly faster network and no longer any problems with communication between devices on the network.

Hi  @Joseph-TP 

this router (TP-Link VX800v) cannot be obtained through an ISP in Germany. They typically offer Fritz! products.
This router is only available here through electronics stores, Amazon, or other online retailers.

Therefore, it is clear that the router's software is either faulty or that the option to assign DNS server IP address via RA (router advertisements) has not been implemented.

As far as I know, other routers are indeed capable of providing an alternative DNS server via RA (e.g., Fritz!Box).

I bought this router precisely so I could access all settings and configure my network myself. 

This wasn't the case with other routers, or they were simply far too expensive.

It's a shame that this router also doesn't support everything you need for a home lab.
Apparently, I have to spend a lot of money on business-grade equipment to get the range of features I want and need.

Hawk18x wrote

  @Martin-B 

Hi,

a few days ago, I found a solution that works well.

Even when "IPv6 LAN" is disabled, the router always provides a local IPv6 address via "fe80::".
(You can find this IP on "Extendes Settings -> Overview -> IPv6-Standardgateway")

If you use this IPv6 address and, for example, use "PiHole" as the DNS server on the network, you can use RADVD in PiHole, provided the gateway of the computer running PiHole is set to this "fe80" IP address and the computer itself has IPv6 addresses.

Using the built-in RADVD function, Pi-hole provides its own IPv4 and IPv6 addresses to the clients as primary DNS server.

Therefore, an active "IPv6 LAN" on the router is no longer necessary.

Since then, I have a significantly faster network and no longer any problems with communication between devices on the network.

 

  @Hawk18x 

Hi,

that's an interesting finding.

But I have to adapt it to my setting. I don't have PiHole, I switched to AdguardHome (on my Raspberry Pi) some years ago.
Since I had problems with AdguardHome DHCPv6 regarding RA, I used radvd for that purpose.
When "IPv6 LAN" is disabled, my Pi has some fe80:: address (SLAC based I think). 
So when I understand your solution right, then I have to assign Pi the fixed IPv6-Standardgateway fe00:: address that is noted in the routers overview panel. 
I.e. that will be my local IPv6 DNS address to provide by radvd. 
But I also need GUA IPv6 addresses that can be routed by the router from/to the internet.
The router provides a (dynamic/changeable) IPv6 prefix 2001:: which I see below the IPv6-Standardgateway you've mentioned.
That would result in adding an additional GUA address range by radvd.
The problem with that is, how to identify that prefix automatically when changed. By the way, I've noticed, that it is not available via SNMP (when enabled).

Just an additional note: M-Net ISP in Germany now has TP-Link VX800v as standard router for their customers. But these devices have firmware that is more than a year old.
And as said, I don't know whether that functionality is limited.