What are the common VPN protocols? What are the differences between them?

VPN protocols are technical specifications that define how VPN connections are established, maintained, and terminated. Different VPN protocols have varying characteristics in terms of security, performance, compatibility, and configuration complexity.

Comparison of major VPN protocols:

1. PPTP (Point-to-Point Tunneling Protocol)

   • Pros: Simple configuration, good compatibility, fast speed
   • Cons: Lower security, proven vulnerabilities
   • Use cases: Scenarios with low security requirements
   • Encryption: Uses MPPE encryption with weak key length

2. L2TP/IPsec (Layer 2 Tunneling Protocol with IPsec)

   • Pros: Good security, widely supported
   • Cons: Slower speed, complex configuration
   • Use cases: Enterprise environments requiring higher security
   • Encryption: Uses AES encryption from IPsec

3. OpenVPN

   • Pros: Open source and free, high security, highly configurable, can bypass firewalls
   • Cons: Relatively complex configuration, requires third-party clients
   • Use cases: Personal and enterprise users needing high security and flexibility
   • Encryption: Supports multiple encryption algorithms including AES, ChaCha20

4. IKEv2 (Internet Key Exchange version 2)

   • Pros: Stable connection, fast reconnection, suitable for mobile devices
   • Cons: Mainly supported on Windows and mobile devices
   • Use cases: Mobile devices, unstable network environments
   • Encryption: Uses strong encryption algorithms like AES-GCM

5. WireGuard

   • Pros: Small codebase, excellent performance, modern encryption algorithms
   • Cons: Relatively new, some features still under development
   • Use cases: Modern VPN deployments requiring high performance
   • Encryption: Uses modern algorithms like ChaCha20, Curve25519

When choosing a VPN protocol, consider:

• Security requirements
• Performance needs
• Device compatibility
• Network environment
• Configuration complexity