my Raspberry can't resolve any DNS after a fresh install (august 2022 version of hifiberryos). The configuration seems correct to me. There is no firewall installed. Name resolution works only within the lan.
# route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 192.168.1.1 0.0.0.0 UG 0 0 0 eth0
172.17.0.0 0.0.0.0 255.255.0.0 U 0 0 0 docker0
192.168.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
# systemd-resolve
Global
Protocols: +LLMNR +mDNS DNSOverTLS=opportunistic
DNSSEC=allow-downgrade/unsupported
resolv.conf mode: uplink
Fallback DNS Servers: 1.1.1.1#cloudflare-dns.com
8.8.8.8#dns.google
1.0.0.1#cloudflare-dns.com
8.8.4.4#dns.google
2606:4700:4700::1111#cloudflare-dns.com
2001:4860:4860::8888#dns.google
2606:4700:4700::1001#cloudflare-dns.com
2001:4860:4860::8844#dns.google
Link 2 (dummy0)
Current Scopes: none
Protocols: -DefaultRoute +LLMNR -mDNS
DNSOverTLS=opportunistic
DNSSEC=allow-downgrade/supported
Link 3 (eth0)
Current Scopes: DNS LLMNR/IPv4 LLMNR/IPv6
Protocols: +DefaultRoute +LLMNR -mDNS
DNSOverTLS=opportunistic
DNSSEC=allow-downgrade/unsupported
Current DNS Server: 9.9.9.9
DNS Servers: 9.9.9.9 1.1.1.1
Link 4 (wlan0)
Current Scopes: none
Protocols: -DefaultRoute +LLMNR -mDNS
DNSOverTLS=opportunistic
DNSSEC=allow-downgrade/supported
Global
Global
Protocols: +LLMNR +mDNS DNSOverTLS=opportunistic DNSSEC=allow-downgrade/unsupported
resolv.conf mode: uplink
Fallback DNS Servers: 1.1.1.1#cloudflare-dns.com 8.8.8.8#dns.google 1.0.0.1#cloudflare-dns.com 8.8.4.4#dns.google
2606:4700:4700::1111#cloudflare-dns.com 2001:4860:4860::8888#dns.google
2606:4700:4700::1001#cloudflare-dns.com 2001:4860:4860::8844#dns.google
Link 2 (dummy0)
Current Scopes: none
Protocols: -DefaultRoute +LLMNR -mDNS DNSOverTLS=opportunistic DNSSEC=allow-downgrade/supported
Link 3 (eth0)
Current Scopes: DNS LLMNR/IPv4 LLMNR/IPv6
Protocols: +DefaultRoute +LLMNR -mDNS DNSOverTLS=opportunistic DNSSEC=allow-downgrade/unsupported
Current DNS Server: 9.9.9.9
DNS Servers: 9.9.9.9 1.1.1.1
Link 4 (wlan0)
Current Scopes: none
Protocols: -DefaultRoute +LLMNR -mDNS DNSOverTLS=opportunistic DNSSEC=allow-downgrade/supported
Link 5 (docker0)
Current Scopes: none
Protocols: -DefaultRoute +LLMNR -mDNS DNSOverTLS=opportunistic DNSSEC=allow-downgrade/supported
# ntpdate -q pool.ntp.org
Error resolving pool.ntp.org: Name or service not known (-2)
1 Sep 15:07:38 ntpdate[1986]: Can't find host pool.ntp.org: Name or service not known (-2)
1 Sep 15:07:38 ntpdate[1986]: no servers can be used, exiting
nslookup has no reply
ping works on the lan but not outside on the internet
# systemd-resolve audio.local
audio.local: 192.168.1.3 -- link: eth0
172.17.0.1 -- link: docker0
fe80::ba27:ebff:fed6:4c5c%3 -- link: eth0