Interpreting the output from systemd-resolve --status

Question

It seems that on newer Linux systems you can no longer check the DNSs by doing cat /etc/resolv.conf. It is now done by systemd-resolve --status.

Below is an example output of that command:

user@user:~$ systemd-resolve --status
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
                      corp
                      d.f.ip6.arpa
                      home
                      internal
                      intranet
                      lan
                      local
                      private
                      test

Link 3 (wlp4s0)
      Current Scopes: DNS LLMNR/IPv4 LLMNR/IPv6
       LLMNR setting: yes
MulticastDNS setting: no
      DNSSEC setting: no
    DNSSEC supported: no
         DNS Servers: fe80::e695:6eff:fe40:9af2
          DNS Domain: lan

The description states:

--status

Shows the global and per-link DNS settings in currently in effect.

What does the Global section represent, what to those addresses represent and how are they related to DNSs?

Answer 1

The systemd-resolve documentation says:

The DNS servers contacted are determined from the global settings in /etc/systemd/resolved.conf, the per-link static settings in /etc/systemd/network/*.network files, the per-link dynamic settings received over DHCP and any DNS server information made available by other system services.

It think this explains your Global flag.

DNSSEC NTA stands for DNSSEC Negative Trust Anchor. This applies to domains that are not signed or not correctly signed to "override" DNSSEC data, by disabling DNS validation for the specific domain. See RFC7646, which I quote:

NTAs are configured locally on a validating DNS recursive resolver to shield end users from DNSSEC-related authoritative name server operational errors. NTAs are intended to be temporary and only implemented by the organization requiring an NTA (and not distributed by any organizations outside of the administrative boundary).