What is the way to decide how a packet will move from an untrusted outside...

Firewalking is a technique used to determine what layer 4 protocols a firewall will allow by sending crafted packets with TTL values that expire at the firewall and analyzing ICMP Time Exceeded responses. This helps in determining what ports and services are allowed through a firewall.

???? Reference – CEH v13 Study Guide, Module 11: Evading IDS, Firewalls, and Honeypots

“Firewalking is a technique used to gather information about firewalls and their rule sets by sending packets with TTL values that expire at the firewall.”

❌ Incorrect options:

A. Session hijacking refers to taking over an active session.

C. MITM attacks involve intercepting communications between two parties.

D. Network sniffing involves capturing packets, not probing firewall rules.