Update 04/08/2022

Rather than a new test case, this issue relates to updating the specification of Zone01 with further testing.

The SOA MNAME is supposed to be the master server of the zone. Currently Zonemaster does not do much tests of that server. This issue proposes a new test case with the following verifications of SOA MNAME:

• That the server responds to DNS queries.
• That the server is authoritative to the zone.
• That the SOA serial is identical to the NS name servers.

From RFC 1035:

MNAME The of the name server that was the
original or primary source of data for this zone.

From RFC 1996:

Primary Master master server at the root of the zone transfer
dependency graph. The primary master is named in the
zone's SOA MNAME field and optionally by an NS RR.
There is by definition only one primary master server
per zone.

From RFC 2136:

Primary Master master server at the root of the AXFR/IXFR
dependency graph. The primary master is named in
the zone's SOA MNAME field and optionally by an NS
RR. There is by definition only one primary master
server per zone.

From RFC 2181:

It is quite clear in the specifications, yet seems to have been
widely ignored, that the MNAME field of the SOA record should contain
the name of the primary (master) server for the zone identified by
the SOA. It should not contain the name of the zone itself. That
information would be useless, as to discover it, one needs to start
with the domain name of the SOA record - that is the name of the
zone.