Many bus methods systemd-resolved exposes (in particular the
resolver methods such as ResolveHostname() on the Manager
interface) may return some of the following errors:
org.freedesktop.resolve1.NoNameServers
No suitable DNS servers were found to resolve a request.
org.freedesktop.resolve1.InvalidReply
A response from the selected DNS server was not understood.
org.freedesktop.resolve1.NoSuchRR
The requested name exists, but there is no resource record of
the requested type for it. (This is the DNS NODATA case).
org.freedesktop.resolve1.CNameLoop
The look-up failed because a CNAME or DNAME loop was
detected.
org.freedesktop.resolve1.Aborted
The look-up was aborted because the selected protocol became
unavailable while the operation was ongoing.
org.freedesktop.resolve1.NoSuchService
A service look-up was successful, but the SRV record reported
that the service is not available.
org.freedesktop.resolve1.DnssecFailed
The acquired response did not pass DNSSEC validation.
org.freedesktop.resolve1.NoTrustAnchor
No chain of trust could be established for the response to a
configured DNSSEC trust anchor.
org.freedesktop.resolve1.ResourceRecordTypeUnsupported
The requested resource record type is not supported on the
selected DNS servers. This error is generated for example
when an RRSIG record is requested from a DNS server that does
not support DNSSEC.
org.freedesktop.resolve1.NoSuchLink
No network interface with the specified network interface
index exists.
org.freedesktop.resolve1.LinkBusy
The requested configuration change could not be made because
systemd-networkd(8), already took possession of the interface
and supplied configuration data for it.
org.freedesktop.resolve1.NetworkDown
The requested look-up failed because the system is currently
not connected to any suitable network.
org.freedesktop.resolve1.DnsError.NXDOMAIN,
org.freedesktop.resolve1.DnsError.REFUSED, ...
The look-up failed with a DNS return code reporting a
failure. The error names used as suffixes here are defined in
by IANA in DNS RCODEs
