Tech Matchups: Site-to-Site VPN vs Client VPN
Overview
Site-to-Site VPN connects entire on-premises networks to AWS VPCs, enabling secure network-to-network communication over the internet.
Client VPN allows individual users to securely access AWS VPCs or on-premises networks from remote locations using VPN clients.
Both provide secure access: Site-to-Site for networks, Client VPN for users.
Section 1 - Connectivity Model
Site-to-Site VPN links networks—e.g., connecting an on-premises CIDR (192.168.0.0/16) to a VPC (10.0.0.0/16) via IPsec tunnels. Uses Virtual Private Gateway (VGW).
Client VPN connects users—e.g., a remote employee accessing a VPC subnet (10.0.1.0/24) via an OpenVPN client. Uses Client VPN Endpoint.
Scenario: Site-to-Site VPN for branch office connectivity; Client VPN for remote workers.
Section 2 - Security and Authentication
Site-to-Site VPN uses IPsec with pre-shared keys or certificates for encryption—e.g., AES-256 for secure data transfer. Configured on customer gateways (e.g., Cisco ISR).
Client VPN supports mutual TLS or Active Directory authentication—e.g., integrating with AWS Directory Service for user credentials. Uses TLS 1.2 for encryption.
Scenario: Site-to-Site VPN secures a data center link; Client VPN authenticates developers via AD. Site-to-Site is network-secure; Client VPN is user-secure.
Section 3 - Cost and Scalability
Site-to-Site VPN charges per VGW hour ($0.05 in us-east-1) and data transfer ($0.09/GB out). Example: 1TB/month costs ~$128.40 ($36 hourly + $92.40 data).
Client VPN charges per endpoint hour ($0.10) and connection hour ($0.05). Example: 10 users, 100 hours/month costs ~$86 ($36 endpoint + $50 connections).
Site-to-Site scales to multiple tunnels; Client VPN scales to thousands of users.
Scenario: Site-to-Site for steady network traffic; Client VPN for variable user access.
Section 4 - Use Case Scenarios
Site-to-Site VPN suits hybrid cloud setups—e.g., connecting a corporate data center to an AWS VPC for application integration.
Client VPN fits remote access—e.g., enabling engineers to access a VPC’s private resources from home.
Scenario: Site-to-Site for ERP system sync; Client VPN for admin access to RDS.
Section 5 - Comparison Table
| Aspect | Site-to-Site VPN | Client VPN |
|---|---|---|
| Scope | Network-to-Network | User-to-Network |
| Authentication | IPsec Keys/Certs | TLS/AD |
| Cost | VGW + Data | Endpoint + Connections |
| Scalability | Multiple Tunnels | Thousands of Users |
| Best For | Hybrid Clouds | Remote Access |
Site-to-Site for network links, Client VPN for user access. Choose based on connectivity needs.
Conclusion
Site-to-Site VPN and Client VPN enable secure AWS connectivity for different audiences. Site-to-Site VPN connects entire networks, ideal for hybrid cloud integrations or branch offices. Client VPN empowers individual users, perfect for remote work or administrative access.
Weigh scope (network vs. user), authentication (IPsec vs. AD), and cost (data vs. connections). Use Site-to-Site for infrastructure, Client VPN for users—or combine: Site-to-Site for core connectivity, Client VPN for remote access.