The process of transferring information in the zone file on a primary name server to a secondary name server. You would do this in the following situations:
In Microsoft’s implementation of DNS on Microsoft Windows NT, zone transfers occur in three circumstances:
A zone transfer is always initiated by the secondary name server. Typically, the secondary name server periodically contacts the primary name server to determine whether any changes have been made to the primary name server’s zone file. If so, it initiates a request for zone transfer. Specifically, when the refresh interval expires on the secondary name server, the following occurs:
Graphic Z-2. Zone transfer in standard DNS on Windows NT.
The dynamic update standard supported by Microsoft Windows 2000 allows zone information to be transferred by using updates. The entire contents of the zone file are not sent when a change is made to a resource record in the file. This method is called incremental zone transfer and is defined in Request for Comments (RFC) 1995.