Understanding VPNs: How They Work and When to Use Them
Learn what VPNs do, how tunneling protocols encrypt your traffic, and when a VPN is (and is not) the right solution.
Last updated Apr 7, 2026Current
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Learn what VPNs do, how tunneling protocols encrypt your traffic, and when a VPN is (and is not) the right solution.
A Virtual Private Network (VPN) creates an encrypted tunnel between your device and a remote server. All network traffic traveling through this tunnel is protected from eavesdropping, even on untrusted networks like public Wi-Fi. The VPN server then forwards your traffic to its final destination, making it appear as though your connection originates from the server's location rather than your own.
VPN protocols wrap your original data packets inside an additional layer of encryption before sending them across the internet. When the encrypted packet reaches the VPN server, it strips the outer layer and forwards the original packet to its destination.
IPsec is one of the oldest and most widely deployed protocols. It operates at the network layer and supports two modes: transport mode (encrypts only the payload) and tunnel mode (encrypts the entire packet). IPsec is commonly used for site-to-site VPNs connecting office networks.
OpenVPN is an open-source protocol that uses TLS for key exchange and can run over TCP or UDP. It is highly configurable and widely supported across platforms. Many organizations prefer it for remote access VPNs because of its flexibility and strong security track record.
WireGuard is a newer protocol that aims for simplicity and performance. Its codebase is roughly 4,000 lines compared to OpenVPN's 100,000+, which makes it easier to audit. WireGuard uses modern cryptographic primitives and generally offers better throughput and lower latency.
Consumer VPN services (like NordVPN or ExpressVPN) are designed for privacy. They mask your IP address and encrypt traffic between you and the provider's server. They are useful for protecting yourself on public networks or accessing geo-restricted content.
Enterprise VPNs serve a different purpose. They provide remote employees with secure access to internal corporate resources. When you connect to a corporate VPN, you essentially join the company's private network as if you were physically in the office. This lets you access internal applications, file shares, and databases that are not exposed to the public internet.
VPNs protect data in transit but do nothing to secure the endpoints themselves. If your laptop is compromised with malware, the VPN faithfully tunnels that malicious traffic right into the corporate network. This is one reason organizations are shifting toward zero trust architectures, which verify every request regardless of network location.
VPNs also create a binary trust model: you are either on the network or off it. Once connected, a user typically has broad access. Zero trust replaces this with continuous, granular verification.
Split tunneling allows some traffic to go through the VPN while the rest uses the regular internet connection. This reduces bandwidth on the VPN gateway and improves performance for non-sensitive traffic like streaming or personal browsing.
However, split tunneling introduces risk. If a user's device is on both the corporate network (via VPN) and the public internet simultaneously, it can serve as a bridge for attackers. Organizations must weigh performance benefits against this increased attack surface.
If you are setting up a VPN for a small team, WireGuard offers the best combination of simplicity and performance. For enterprise deployments, evaluate whether you genuinely need a full-tunnel VPN or whether a zero trust network access (ZTNA) solution would better fit your security model. Always enforce multi-factor authentication on VPN connections, and monitor for unusual connection patterns like logins from unexpected geographies or at unusual hours.
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