Firewalking is a technique developed by Mike Schiffman and David Goldsmith that employs traceroute-like techniques to analyze IP packet responses to determine gateway ACL filters and map networks. Firewalk the tool employs the technique to determine the filter rules in place on a packet forwarding device. The newest version of the tool, firewalk/GTK introduces the option of using a graphical interface and a few bug fixes.
You can download it from the following link: https://packetstormsecurity.com/files/download/10767/firewalk-0.99.1.tar.gz
Source: https://packetstormsecurity.com/files/10767/firewalk-0.99.1.tar.gz.html