Hi all,
NetworkManager connections with an explicit DoT (DNS over TLS) configuration are not supported with Netplan, but NetworkManager does feed back the DoT DNS info with server address and Server Name Indication (SNI) in the form server_address#SNI, e.g. 1.2.3.4#dns.myhome.com as nameserver addresses to Netplan. As a result, subsequent Netplan config applications fail because DNS servers don’t have the expected dotted decimal (IPv4) or colon’ed hex (IPv6) form.
nmcli> describe ipv4.dns
=== [dns] ===
[NM property description]
Array of IP addresses of DNS servers. For DoT (DNS over TLS), the SNI server name can be specified by appending "#example.com" to the IP address of the DNS server. This currently only has effect when using systemd-resolved.