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citecite

Member

Registered: 2018-03-29

Posts: 8

[SOLVED] systemd-resolved doesn't ignore DNSv6 server from RA

Hello world,

I'm trying to get systemd-resolved to ignore my router's built in DNS server, which is advertised as fd00::ca0e:14ff:febf:1dda. My network configuration looks like this:

# cat /etc/systemd/network/50-wired.network
[Match]
Name=enp2s0

[Network]
Address=192.168.10.13/24
Gateway=192.168.10.1
DNS=127.0.0.1 ::1
Domains=home.example.net kvm.example.net example.net

[IPv6AcceptRA]
UseDNS=false

However, systemd-resolved is still using the IPv6 server received from my router:

Global
          DNSSEC NTA: 10.in-addr.arpa
                      16.172.in-addr.arpa
                      168.192.in-addr.arpa
                      17.172.in-addr.arpa
                      18.172.in-addr.arpa
                      19.172.in-addr.arpa
                      20.172.in-addr.arpa
                      21.172.in-addr.arpa
                      22.172.in-addr.arpa
                      23.172.in-addr.arpa
                      24.172.in-addr.arpa
                      25.172.in-addr.arpa
                      26.172.in-addr.arpa
                      27.172.in-addr.arpa
                      28.172.in-addr.arpa
                      29.172.in-addr.arpa
                      30.172.in-addr.arpa
                      31.172.in-addr.arpa
                      box
                      corp
                      d.f.ip6.arpa
                      home
                      internal
                      intranet
                      lan
                      local
                      private
                      test

Link 2 (enp2s0)
      Current Scopes: DNS LLMNR/IPv4 LLMNR/IPv6
       LLMNR setting: yes
MulticastDNS setting: no
      DNSSEC setting: allow-downgrade
    DNSSEC supported: yes
         DNS Servers: 127.0.0.1
                      ::1
                      fd00::ca0e:14ff:febf:1dda
          DNS Domain: home.example.net
                      kvm.example.net
                      example.net

Is there a way to accept RAs for IPv6 configuration but ignore DNS advertisements?

Thanks,
Stefan

Last edited by citecite (2018-06-09 18:32:03)

citecite

Member

Registered: 2018-03-29

Posts: 8

Re: [SOLVED] systemd-resolved doesn't ignore DNSv6 server from RA

Oh dear. It seems that systemd-networkd will, upon receiving and accepting any type of RA, also accept DHCPv6 responses. My router did send those, too, although they "only" contain the local DNS server. So, to disable any dynamic DNS server configuration:

[Match]
Name=enp2s0

[Network]
Address=192.168.10.13/24
Gateway=192.168.10.1
DNS=127.0.0.1
Domains=home.example.net kvm.example.net example.net

[DHCP]
UseDNS=false

[IPV6ACCEPTRA]
UseDNS=false