dnsmap was originally released back in 2006 and was inspired by the fictional story “The Thief No One Saw” by Paul Craig, which can be found in the book “Stealing the Network – How to 0wn the Box”.
First what Fierce is not. Fierce is not an IP scanner, it is not a DDoS tool, it is not designed to scan the whole Internet or perform any un-targeted attacks. It is meant specifically to locate likely targets both inside and outside a corporate network.
Firewalk is an active reconnaissance network security tool that attempts to determine what layer 4 protocols a given IP forwarding device will pass. Firewalk works by sending out TCP or UDP packets with a TTL one greater than the targeted gateway.