Updating bind dns records
If a global notify statement is 'no' this statement may be used to override it for a specific zone and, conversely, if the global options contain a also-notify list, setting notify 'no' in the zone will override the global option.
This statement may be used in normal zone, view or a global options clause.
allow-update defines an address_match_list of hosts that are allowed to submit dynamic updates for master zones, and thus this statement enables Dynamic DNS.
The default in BIND 9 is to disallow updates from all hosts, that is, DDNS is disabled by default.
This statement may be used in a zone, view or global options clause.
Defines how the server calculates incremental zone changes.
From BIND9.10 the statement also allows the use of a Diff Serv Differentiated Service Code Point (DSCP) number (range 0 - 95, where supported by the OS) to be used to identify the traffic classification.
Many people like to be cautious in case the default mode changes.
masters-list may be used to reference a list of servers (slaves) defined in a masters clause each of which will be sent a NOTIFY.
The key-name field defines the key to be used to authenticate the NOTIFY when using TSIG and references the name of a key clause; a corresponding key clause with the same key-name must be present in the slave server(s) for the zone.
The gp-num parameter changes the port number used for NOTIFY for all the listed servers (the default is port 53).
The p-num parameter changes the port number for the specific IP address only.