What is the purpose of firewalking?

What is the purpose of firewalking?

A.
It’s a technique used to discover what rules are configured on a gateway

B.
It’s a technique used to discover interface in promiscuous mode

C.
It’s a technique used to map routers on a network link

D.
It’s a technique used to discover Wireless network on foot

Explanation:
Firewalking uses a traceroute-like IP packet analysis to determine whether or not a particular packet can pass from the attacker’s host to a destination host through a packet-filtering device. This technique can be used to map ‘open’ or ‘pass through’ ports on a gateway. More over, it can determine whether packets with various control information can pass through a given gateway.