Incremental Zone Transfer (IXFR)

Incremental Zone Transfer, or IXFR, is a Domain Name System mechanism used to update DNS zone data between authoritative DNS servers. Unlike a full zone transfer using AXFR, IXFR transfers only the changes made since a previous version of the zone. These changes can include newly added, modified or deleted DNS records. This allows a secondary DNS server to update its existing zone data without transferring the complete zone each time. The approach can significantly reduce the amount of data transferred and network traffic, particularly for large DNS zones that are updated frequently. IXFR therefore supports efficient synchronisation between redundant DNS servers and helps maintain consistent and up-to-date DNS information.