What Is VPN Split Tunneling?

For users who are looking for an ideal balance between performance and security of their networks, split tunneling can be your answer. Split tunneling offers you a sophisticated method for directing specific internet traffic via a virtual private network (VPN) while permitting other data to directly connect. In essence, it “splits” the traffic based on user-defined rules.

By understanding split tunneling, you can achieve a balanced approach to online security and efficiency for your network, connected devices and users. This article delves into its intricacies and importance in the modern network landscape.

How VPN Split Tunneling Works

VPN split tunneling is a critical feature for many individuals and businesses as it dictates how traffic is channeled through or outside a VPN connection. Here we discuss the split tunneling mechanism step by step:

1. Establishing the VPN connection: As with any VPN session, the process begins when a user connects to a VPN server. This creates an encrypted “tunnel” between the user’s device and the server.
2. Defining traffic rules: With enabled split tunneling, the system administrator or the user specifies which traffic should go via the VPN tunnel and which traffic should bypass it. These rules can be based on IP addresses, specific apps or even domain names.
3. Routing through the tunnel: Traffic that’s designated to be protected will pass through the VPN tunnel. This means it gets encrypted, routed to the VPN server, decrypted and then sent to its final destination on the internet.
4. Routing outside the tunnel: Traffic that’s specified to bypass the VPN without encryption directly goes to its destination. Similar to any standard internet connection without a VPN.
5. Receiving data: When data packets are returned from the web, they take the reverse journey. For packets that went through the VPN, they travel back through the VPN server, get encrypted and then are sent back to the user’s device where they are decrypted. For the packets that bypassed the VPN, they return directly without any detour.

Types of VPN Split Tunneling

Split tunneling in VPNs can be categorized based on how the traffic is defined or directed. Each type of split tunneling has its own use cases and advantages, but they all offer a higher level of granularity and control over how traffic is managed in comparison to a full-tunnel VPN setup. It’s crucial to understand your needs and potential security risks when deciding which type of split tunneling to use.

Here we discuss the main types of split tunneling.

Application-based Split Tunneling

This is perhaps the most common way users interact with split tunneling. In this method, you specify which applications use the VPN and which ones don’t. For instance, you might decide to route your web browser traffic through the VPN for privacy, but let a video streaming app bypass the VPN for better streaming quality.

Address-based Split Tunneling

Here, split tunneling is regulated based on destination IP ranges or addresses. For instance, if you’re remotely working for a company, you might route traffic directed to your company’s IP range through the VPN but let other traffic directly go to the internet.

Protocol-based Split Tunneling

Traffic can be divided based on specific protocols, such as TCP or UDP, or based on specific port numbers. This is more technical and might be used in more specialized scenarios. For instance, you might route file transfer protocol (FTP) traffic, which uses specific ports, through the VPN, but allow HTTP/HTTPS traffic to go directly to the internet.

Inverse Split Tunneling

This is relatively the opposite of traditional split tunneling. Instead of specifying what traffic should use the VPN or traffic should not use it. By default, all other traffic would then pass through the VPN.

URL-based Split Tunneling

Some advanced VPN solutions allow for split tunneling based on specific URLs or domain names. This can be particularly useful for businesses that want to ensure specific websites or web applications always use a secure connection while others do not.

Full Tunneling vs. Split Tunneling

Full tunneling involves routing all of a device’s internet traffic through a VPN tunnel, ensuring every application or service accesses the internet securely via the VPN. This method provides consistent encryption across all activities, ensuring robust security. However, it may lead to slow speed due to the underlying encryption and can complicate the procedure of accessing local network resources. It’s a blanket approach, offering you simplicity at the cost of potential reduction in speed and local access issues.

In contrast, split tunneling allows users to designate which specific traffic goes through the VPN, while the rest connects directly to the internet. This approach provides flexibility as users can selectively protect sensitive data and potentially enjoy better performance for apps that do not need VPN-level security. At the same time, there’s a risk of exposing non-VPN traffic to potential threats, especially on unsecured networks. While it offers an optimized blend of speed and security, it necessitates careful configuration to strike the right balance.

Choosing between the two depends on organizational or individual priorities, encompassing factors, such as desired performance, specific use cases and security concerns.

Benefits of VPN Split Tunneling

Split tunneling offers a range of benefits, especially when you need a balance between security, performance and flexibility. Here are the primary advantages:

• Selective protection: You can choose which specific traffic or applications require the encryption and security of the VPN. This ensures that sensitive activities remain protected while other, less-sensitive activities can run without the overhead of encryption.
• Optimized Performance: Routing all traffic via a VPN can sometimes reduce connection speeds, especially if the VPN server is congested or geographically distant. With split tunneling, unnecessary applications can bypass the VPN, leading to better performance for those tasks.
• Simultaneous local and remote access: You can access local network resources, such as printers or local file shares, without disconnecting from the VPN. This is particularly beneficial for remote workers who might need to access both local and company resources.
• Reduced bandwidth consumption: For organizations with many remote workers, sending all traffic through a corporate VPN can strain the company’s internet bandwidth. Split tunneling ensures only critical business traffic uses the corporate network, potentially leading to cost savings and better performance.
• Avoids VPN restrictions: Some websites or services might block or limit VPN traffic. Split tunneling allows users to access these services directly, without having to disconnect from the VPN entirely.
• Flexibility and control: Split tunneling gives users or information technology (IT) administrators granular control over the network configuration, allowing them to tailor the setup based on individual or organizational needs.
• Better streaming and gaming: Some activities, such as gaming or streaming, require optimal speeds and might not always need the VPN protection. Split tunneling lets users exclude such applications from the VPN for enhanced performance.

Risks of VPN Split Tunneling

Here we discuss risks specifically associated with split tunneling in the context of VPN usage. Understanding these risks is crucial when considering or implementing split tunneling. Proper setup, regular audits and user education can help in mitigating many of these concerns:

• Incomplete encryption: One of the primary risks of split tunneling is that not all internet traffic is encrypted. While certain apps or destinations might be secured through the VPN, others are not, leaving them vulnerable to potential eavesdropping or malicious interception.
• Increased attack surface: With traffic going both through and outside the VPN, there are multiple pathways for potential cyberattacks. If a malicious actor compromises the non-VPN traffic, it might also serve as a launchpad to infiltrate the rest of the device or network.
• Complex configuration: Setting up split tunneling requires precision. Mistakes in configuration can lead to security vulnerabilities, exposing certain traffic or applications unintentionally.
• Inconsistent security postures: With some traffic encrypted and some not, there might be inconsistencies in security protocols or measures. This can lead to complications in monitoring or managing security.
• Difficulty in monitoring: For organizations, monitoring network traffic for any potential threats can become very complex. Traffic outside the VPN might not get monitored or scanned as effectively as the traffic within, potentially letting threats go unnoticed.
• Potential for end-user errors: Users might misunderstand which of their applications or connections are secured and which are not, leading to risky online behavior that ends in sensitive data leaks.

When Should You Use VPN Split Tunneling?

VPN split tunneling is particularly beneficial in scenarios where optimizing performance is as crucial as maintaining security. For instance, remote workers might employ split tunneling to access corporate resources via the VPN while simultaneously streaming music or video directly, without overwhelming the VPN or compromising speed.

Likewise, users who want to ensure their web browsing is private might channel only their browser traffic via the VPN, while local file sharing or online gaming occurs outside the VPN to avoid latency.

Essentially, split tunneling offers a balance, making it ideal when there’s a need to marry the efficiency of direct connections with the security of a VPN.

Bottom Line

Throughout this article, we delved into the intricacies of VPN split tunneling, highlighting its advantages, such as selective protection and optimized performance while also addressing its inherent risks, such as incomplete encryption and configuration complexities.

In essence, while split tunneling offers a nuanced approach to online privacy and performance, understanding its trade-offs and implementing it judiciously is crucial. As with any tool, its value is determined by its appropriate and informed use.

Frequently Asked Questions (FAQs)