systemd-resolved

Next generation DNS resolve scheme.

0. Recommended DNS servers

• IPv4

  • 208.67.222.222
  • 8.8.4.4

• IPv6

  • 2001:4860:4860::8888
  • 2620:119:53::53

1.Examine DNS status

resolvectl status

Tip: With systemd-resolved.service, 127.0.0.53#53(127.0.0.53) is the local DNS server for resolving.

2.Configure Global interface DNS

sudo vim /etc/systemd/resolved.conf

In [Resolve] section, modify the DNS ip:

[Resolve]
DNS=208.67.220.220 208.67.222.222

(Advanced)Custom Global DNS target

sudo vim /etc/systemd/resolved.conf

In [Resolve] section, modify the Domains:

[Resolve]
Domains=~. ~github.com ~microsoft.com

In Domains field, Specify which domain you want to reolve prefix with ~.

⚠️ ~. means resolve the root DNS(.), but there are usually two ~. value of different items shown by resolvectl status. One is Golbal, another is Link which is dynamic set by receiving over DHCP, information provided via NetworkManager.

💩 Usually, Link [NUM] interface (generated by DHCP, local dns) is faster than Global, so software prefer to use it because both have ~. value in Domains field. That's why Global need to speficy Domains value in /etc/systemd/resolved.conf file.

Active configuration

systemctl restart systemd-resolved.service

3.Configure Link [NUM] interface DNS

Its DNS configuration is from NetworkManager, for example:

Link 3 (wlp3s0)
    Current Scopes: DNS LLMNR/IPv4 LLMNR/IPv6                                   
         Protocols: +DefaultRoute +LLMNR -mDNS -DNSOverTLS DNSSEC=no/unsupported
Current DNS Server: 208.67.222.222                                              
       DNS Servers: 1.1.1.1 208.67.222.222 208.67.220.220                       
        DNS Domain: ~.                                                          

NetworkManager Configure file:

Previous:

cd /etc/sysconfig/network-scripts/		#Location
man nm-settings-ifcfg-rh			#Reference

Present:

cd /etc/NetworkManager/system-connections/	#Location
man nm-settings					#Reference

Custom DNS ip and abandon ISP DNS ip

dns=1.1.1.1;208.67.222.222;208.67.220.220;	#semicolon(;)
ignore-auto-dns=true

⚠️ Use semicolon(;) to split multiple DNS ip, if any.

Active configuration

systemctl restart NetworkManager.service