I read some topics here about Pi-hole not blocking IPv6 resolution of blocked domains - because the router advertises himself (or provider DNS servers in my case) and every client in the network uses those to resolve and not the Pi-hole one.
Sadly in my router (Technicolor from cablesurf) there's no option to turn off / configure those DNS servers - I feel like I'm not the admin of my own network...
So I thought: I additionally can announce my (Pi-hole) RDNS with higher priority, and then the clients use this DNS first.
So I deployed radvd (1:2.15-2) with this config on the Pi-hole:
interface eth0
{
AdvSendAdvert on;
AdvOtherConfigFlag on;
AdvDefaultPreference high;
RDNSS [IPv6 of Pi-hole]
{
};
};
With radvddump I can see both router announcements on my network:
#
# radvd configuration generated by radvdump 2.15
# based on Router Advertisement from fe80::c42:fba:d254:4207
# received by interface eth0
#
interface eth0
{
AdvSendAdvert on;
# Note: {Min,Max}RtrAdvInterval cannot be obtained with radvdump
AdvManagedFlag off;
AdvOtherConfigFlag on;
AdvReachableTime 0;
AdvRetransTimer 0;
AdvCurHopLimit 64;
AdvDefaultLifetime 1800;
AdvHomeAgentFlag off;
AdvDefaultPreference high;
AdvSourceLLAddress on;
RDNSS [IPv6 of Pi-hole]
{
AdvRDNSSLifetime 600;
}; # End of RDNSS definition
}; # End of interface definition
#
# radvd configuration generated by radvdump 2.15
# based on Router Advertisement from fe80::725a:9eff:fe3d:4bb1
# received by interface eth0
#
interface eth0
{
AdvSendAdvert on;
# Note: {Min,Max}RtrAdvInterval cannot be obtained with radvdump
AdvManagedFlag on;
AdvOtherConfigFlag on;
AdvReachableTime 0;
AdvRetransTimer 0;
AdvCurHopLimit 64;
AdvDefaultLifetime 1800;
AdvHomeAgentFlag off;
AdvDefaultPreference medium;
AdvSourceLLAddress on;
prefix 2001:4c50:[redacted]/64
{
AdvValidLifetime 27000;
AdvPreferredLifetime 25200;
AdvOnLink on;
AdvAutonomous on;
AdvRouterAddr off;
}; # End of prefix definition
route 2001:4c50:[redacted]/56
{
AdvRoutePreference medium;
AdvRouteLifetime 27000;
}; # End of route definition
RDNSS 2001:4c50:6:4000::12 2001:4c50:6:4000::16
{
AdvRDNSSLifetime 60;
}; # End of RDNSS definition
DNSSL cm.cablesurf.de
{
AdvDNSSLLifetime 60;
}; # End of DNSSL definition
}; # End of interface definition
But even after disabling and re-enabling my network interface, this DNS server doesn't show up in my Windows 10 machines:
Ethernet adapter Ethernet:
Connection-specific DNS Suffix . : local
DHCP Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
Default Gateway . . . . . . . . . : fe80::[redacted]
192.168.0.1
DHCP Server . . . . . . . . . . . : 192.168.0.5
DNS Servers . . . . . . . . . . . : 2001:4c50:6:4000::12
2001:4c50:6:4000::16
192.168.0.5
NetBIOS over Tcpip. . . . . . . . : Enabled
Connection-specific DNS Suffix Search List :
cm.cablesurf.de
Is this way not possible or did I do something wrong?