Tunneling is a cybersecurity technique that encapsulates one network protocol within another, allowing data to be securely transmitted across networks that may otherwise block or restrict access. This process creates a 'tunnel' through which data packets can travel, often encrypted, to bypass firewalls, censorship, or network restrictions. Common tunneling protocols include VPN, SSH, and GRE. While tunneling is frequently used for legitimate purposes like securing remote access or ensuring privacy, it can also be exploited by attackers to evade detection and move malicious traffic. Understanding tunneling is essential for both protecting network integrity and detecting unauthorized data flows.