Description of problem: When the system comes up and DNS (in /etc/systemd/resolved.conf) is set to two comma separated addresses DNS=<address1>,<address2> Fails with Failed to add DNS server address '<address1>,<address2>, ignoring: Invalid argument which results in no DNS. Version-Release number of selected component (if applicable): systemd-246.10-1.fc33 How reproducible: 100%
I know this used to work, but *that* was the bug. The addresses must be space-separated: DNS= A space-separated list of IPv4 and IPv6 addresses to use as system DNS servers. Each address can optionally take a port number separated with ":", a network interface name or index separated with "%", and a Server Name Indication (SNI) separated with "#". When IPv6 address is specified with a port number, then the address must be in the square brackets. That is, the acceptable full formats are "111.222.333.444:9953%ifname#example.com" for IPv4 and "[1111:2222::3333]:9953%ifname#example.com" for IPv6. DNS requests are sent to one of the listed DNS servers in parallel to suitable per-link DNS servers acquired from systemd-networkd.service(8) or set at runtime by external applications. For compatibility reasons, if this setting is not specified, the DNS servers listed in /etc/resolv.conf are used instead, if that file exists and any servers are configured in it. This setting defaults to the empty list.