Merge pull request #395 from melroy89/patch-2

Explain the zonefile example better

doc/manual/zonefile.rst

@@ -37,3 +37,14 @@ A minimal zone needs exactly one SOA (Source Of Authority) and one or more NS (N
 
 
 .. could add this structure eventually: <name> <ttl> <class> <type> <rdata>
+
+
+.. Note:: In the example above the ``SOA`` record class is set to: ``IN``. The record class is omitted in the remaining records, in which case the resulting value will be set from the preceding record.
+	Meaning the ``NS``, ``A`` and ``MX`` source records have implicitly the ``IN`` record class.
+
+.. Note:: The first domain in the ``SOA`` (start of authority) record, is the authoritative master name server for the zone. 
+	The second domain is actually the administrator email addresss for this zone. Where the first dot (``.``) will be converted into an ``@`` sign. 
+	So in this example above, the email is: ``noc@dns.example.org``. If you have a dot in the local-part of the email address, you need to backslash the dot.
+
+.. Note:: You can use the ``@`` symbol in the zone file for a shortcut to the origin of the zone domain. 
+	Meaning ``example.com. IN  SOA`` could also have been written to: ``@ IN  SOA``. Same can be applied to other records as well, like the A record: ``@  A  192.0.2.1``. Which is the same as: ``example.com.  A  192.0.2.1``