Penetration testing

DNS zone transfer is a mechanism to replicate DNS data from one DNS server to another. You can add your own DNS server IP address here and set it as a slave (or secondary) server for your zone
http://manual.intl.indoglobal.com/ch03s10.html

DNS zone transfer, also sometimes known by its (most common) opcode mnemonic AXFR, is a type of DNS transaction. It is one of the many mechanisms available for administrators to employ for replicating the databases containing the DNS data across a set of DNS servers. Zone transfer comes in two flavors, full (opcode AXFR) and incremental (IXFR). Nearly universal at one time, it is now becoming less popular in favor of the use of other database replication mechanisms that modern DNS server packages provide

http://en.wikipedia.org/wiki/DNS_zone_transfer