Secure connectivity term: Within enterprises, intranets and extranets often use firewalls and security features to create protected links over the public Internet. What is the standard term for such secure tunnels?

Introduction / Context:
Organizations commonly link sites, remote users, and partners securely over the Internet. Rather than private leased lines, they build encrypted tunnels that provide confidentiality, integrity, and often authentication. This question asks for the widely accepted term for that technology class.

Given Data / Assumptions:

• Communication rides over the public Internet.
• Security controls include encryption and authentication.
• Endpoints are enterprise networks (intranets/extranets) and remote peers.

Concept / Approach:

A Virtual Private Network (VPN) uses protocols such as IPsec or TLS to create secure tunnels over untrusted networks. VPNs can be site-to-site or remote access. They complement firewalls and directory services to enforce policy while providing private connectivity semantics on public infrastructure.

Step-by-Step Solution:

Verification / Alternative check:

Common deployments include IPsec site-to-site VPNs between data centers and SSL/TLS-based remote access VPNs for users. Both fulfill the described requirement.

Why Other Options Are Wrong:

• Network Server: A role, not a secure tunnel technology.
• Network operating system: Software class, not the tunneling method.
• OSI: A reference model, not a product or feature.
• Secure Sockets Layer (SSL): A protocol component; modern TLS can underpin VPNs, but the overall solution is called a VPN.

Common Pitfalls:

Equating a single protocol (for example, SSL/TLS) with the broader deployment concept. The accepted umbrella term for secure site or user tunnels across the Internet is VPN.

Final Answer:

Virtual Private Network