Bind9 not updating zone serial
Serial numbers are used by slave nameservers to determine when a zone transfer is necessary.
This statement may be used in a zone, view or global options clause. IP address(es) that are allowed to transfer (copy) the zone information from the server (master or slave for the zone).
The default behaviour is to allow zone transfers to any host.
However, even when you use a tool, it is critical to know what goes on when the files are updated, so we'll start with the manual method.
After creating your zone data files initially, it should be fairly apparent what you need to change when you add a new host.
However it is possible to achieve the same outcome by performing two separate additions.