Posted on 26.3.2025

Improving site-to-site VPN security and performance for multi-site businesses

In the interconnected business world, a Virtual Private Network (VPN) is more than just a tool for bypassing geo-restrictions. It’s critical for safeguarding your digital footprint, especially when dealing with sensitive business-critical data.

In the post, we explore what site-to-site VPNs offer for businesses, the best practices for strengthening their security and optimizing its performance for multi-cloud and business applications.

Introduction

Site-to-site VPN, commonly used by businesses and organizations, enable secure connections between different office locations or cloud environments. However, simply deploying a VPN is not enough. Enhancing its security and performance is essential to safeguard against evolving threats.

Understanding VPN security

At its core, VPN security relies on encryption and secure protocols. Common encryption standards like AES-256 ensure data confidentiality, while protocols like OpenVPN, WireGuard, and IKEv2/IPSec establish the standards for secure connections.

  • Encryption: Using 256-bit keys is highly recommended, making it harder for malicious actors to decipher your data.
  • Protocols: Each protocol has its strengths and weaknesses. OpenVPN is highly configurable and secure, WireGuard is known for its speed and efficiency, and IKEv2/IPSec is stable and reliable for mobile devices.
  • Authentication: Strong authentication mechanisms, such as digital certificates and pre-shared keys (PSKs), help prevent unauthorized access.
  • Tunnel Integrity: Ensuring that data packets are not altered or intercepted during transmission is vital for VPN security.
Site-To-Site Vpn Network Structure

Advantages of site-to-site VPNs

Site-to-site VPNs provide significant benefits, particularly for businesses and organizations with multiple locations or multi-cloud environments:

Secure Inter-office Connectivity: Establishes encrypted links between branch offices and headquarters, reducing reliance on unsecured public networks.

Multi-cloud Integration: Enables secure connections between different cloud providers, facilitating seamless hybrid cloud deployments.

Cost Savings: Eliminates the need for expensive leased lines or dedicated network infrastructure.

Centralized Security Policies: Allows IT teams to enforce consistent security policies across all connected sites.

Multi-Site Vpn Network Structure

Enhanced security settings and setup

To maximize the security of your VPN, consider implementing the following advanced settings and configurations:

Integrity checks

Data integrity ensures that the transmitted data has not been tampered with during transit. Hash functions, such as SHA-2 (SHA-256 or higher), are used to generate a unique “fingerprint” of the data. If the data is modified, the hash value will change, indicating a potential compromise.

Static routing

Particularly where the business is in control of the networks in all sites, static routing offers an easy and predictable way to configure routing between networks connected using a VPN tunnel. With static routing, site-to-site VPN is configured to route only specific IP subnets ensuring secure connection to company resources without overgrouding the connection.

Multi-Factor Authentication (MFA)

Implementing multi-factor authentication adds an extra layer of security to your company network. Employees must use two or more verification forms to access their account. MFA is a critical security measure for protecting VPN access by verifying the identity of users attempting to connect. The primary objective of MFA is to provide stronger assurance that the individual accessing the VPN is who they claim to be.

Ongoing maintenance and oversight

It’s essential to implement regular maintenance and monitoring practices to ensure your VPN remains secure over time. Here are some essential tips:

  1. Keep your VPN software updated to get the latest security features and fixes. This helps guard against vulnerabilities that attackers could target.
  2. Conduct regular risk assessments and audits to ensure your third-party service provider complies with security requirements.
  3. Actively monitor your VPN usage for any signs of unusual or suspicious activity. This could include unexpected login attempts, changes in data usage patterns, or unfamiliar devices accessing your network.
  4. Use intrusion detection and prevention systems (IDS/IPS) to identify and block malicious traffic.
Vpn Security Example

Combining VPN with additional security measures

While a VPN is an essential tool for securing your online activity, it works best when used in conjunction with other cybersecurity measures for comprehensive protection. Here are some ways to integrate a VPN with other security tools:

  • Firewalls – Use next-generation firewalls (NGFWs) to filter traffic and enforce security policies.
  • Antivirus and Endpoint Protection – Ensure that all connected devices have up-to-date antivirus software to prevent malware infections.
  • Zero Trust Security Model – Adopt a zero-trust approach by verifying every device and user before granting access.
  • Secure Web Gateways – Filter and monitor web traffic to prevent phishing attacks and unauthorized data access.

Conclusion

Enhancing your site-to-site VPN security and performance is essential for safeguarding business-critical data and maintaining a secure network environment. By implementing strong encryption, enforcing strict authentication measures, and regularly monitoring traffic, organizations can ensure robust protection against cyber threats.

Integrating your site-to-site VPN with other cybersecurity tools can further strengthen your protection. Staying proactive and continuously updating security configurations will help safeguard sensitive information in an increasingly digital world.

Janne Ruostemaa

Editor-in-Chief

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