Category Archives: Learning

DNS Server primary/secondary in general

Each primary and secondary zone of the same name on two separate DNS servers contains a serial number.
Peroidically a check is made to determine if the serial number of the primary matches the secondary.
If they do, nothing happens.
If they don’t then the secondary zone is locked and the secondary zone gets the changes (i.e. adds, deletes and changes) to the zone.
Note that I said changes as this makes the update process quicker.
This process repeats over and over again day after day.

Reload from Master

A reload from master is a manual process kicked off by executing a DNSCMD.EXE command line request or
by requesting the process though the DNS Managment Console on the server performing your DNS functions.
When such a request is made the secondary copy get a full and complete reload of
the zone from the primary without regard to the serial numbers or  the time.
Reloads can be done whenever and however frequently you want.

A reload of the Primary zone is typically performed from the Managment Console.
When you invoke the console and display a zone the records in the zone are cached.
When you request a reload you are asking that the cache be completely replaced.

Transfer from Master

Reload will initiate also a flush of all records before downloading from master, but transfer will do only donwload from master.