Backtrack 4: Information Gathering: DNS: Fierce – locate non-contiguous IP space and hostnames against specified domains
The final tool in the DNS Section is called fierce. It is a perl script written by rsnake. Fierce tries multiple techniques to find all the IP addresses and hostnames used by a target. These include – trying to dump the SOA records, do a zone transfer, searching for commonly used domain names with a dictionary attack, adjacency scan and a few more. Fierce is meant specifically to locate likely targets both inside and outside a corporate network. Only those targets are listed (unless the -nopattern switch is used). No exploitation is performed (unless you do something intentionally malicious with the -connect switch). Fierce is a reconnaissance tool. Fierce is a PERL script that quickly scans domains using several tactics.