Changes since SOA version
IXFR is a zone transfer request that returns changes since a specific SOA version. Enter the SOA version to request changes since then.
Not an apex domain
The domain vip.kecd-ddi-g1.net.unsw.edu.au is not the root of its zone.
Instead, try zone transfer on net.unsw.edu.au .
Instead, try zone transfer on net.unsw.edu.au .