Key Points
- Split Tunneling Changes How VPN Traffic Is Routed: Only selected traffic uses the VPN. The rest bypasses it and goes straight to the local network.
- Full Tunneling Centralizes Security, Visibility: Routing everything through the VPN keeps inspection and compliance simple, but it can slow things down and put extra strain on the gateway.
- Split Tunneling Improves Performance, Scalability: Less traffic going through the VPN frees up bandwidth and often makes cloud and internet access faster.
- Security Controls Shift to the Endpoint: Once traffic skips the tunnel, endpoint protection and conditional access keep security from getting compromised.
- Routing Strategy Must Align With Policy Requirements: Regulatory obligations, risk tolerance, and infrastructure capacity should determine whether split tunneling is appropriate.
Virtual Private Networks (VPNs) are a regular fixture in home and enterprise networks today. In a nutshell, they create an encrypted tunnel between an endpoint and a remote network to protect traffic and enforce access policy. There are two types of VPN traffic routing: full tunneling and split tunneling.
This guide explains what VPN split tunneling is, how it compares to the full tunnel VPN model, and how each approach affects security, performance, and operational control. Risks and benefits will be highlighted for both options, enabling IT administrators and organizations to choose an efficient and compliant routing strategy.
Understanding VPN split tunneling and its applications
VPN routing determines how the endpoint traffic is handled when a device is connected to a VPN. The choice between split tunneling and full tunneling directly affects performance, visibility, and security control across endpoints.
📌 Why is understanding split tunneling essential for developing a VPN routing strategy?
- This determines which traffic is subject to centralized inspection and policy enforcement.
- It affects bandwidth consumption and load on VPN gateways.
- It changes the exposure profile of endpoints connected to untrusted networks.
What is split tunneling?
Split tunneling is a VPN routing model where only selected traffic is sent through the encrypted tunnel, while other traffic bypasses it and uses the local network connection.
In practice, this means:
- Traffic headed to corporate resources, like internal subnets or private services, is sent through the VPN.
- Internet-bound or non-corporate traffic uses the device’s local internet connection instead of the tunnel.
- Routing decisions are based on destination, application, or policy rather than forcing all traffic through the VPN.
By limiting which traffic enters the tunnel, split tunneling reduces load on VPN gateways and can improve performance for local and Internet access. However, it also changes how security controls are applied to endpoint traffic.
Split tunneling vs full tunneling: a comparison
In a full tunnel configuration, all device traffic routes through this tunnel, including internet-bound traffic. Meanwhile, in split tunneling, only defined destinations like internal subnets or specific applications use it, while other traffic exits to the local network.
Full tunnel VPN
- This centralizes inspection, logging, and traffic control at the VPN boundary.
- Keeping all traffic inside managed controls makes compliance much simpler to deal with.
- Can introduce latency for cloud and SaaS due to backhauling.
Split tunnel VPN
- Users can go straight to the internet and cloud apps without VPN backhaul getting in the way.
- This improves user experience on bandwidth-constrained high-latency links.
- It shifts some security responsibility to endpoint controls and local networks.
Split tunneling: Typical use cases
Split tunneling is primarily used where users need access to internal resources while still reaching the public internet, all without forcing all traffic through the VPN.
Split tunneling is often used when:
- Remote users need access to internal resources and cloud or internet services at the same time.
- Bandwidth constraints on the VPN concentrator need reduced tunnel traffic.
- Performance for local resources has to be preserved to avoid user impact.
It is less appropriate when:
- All traffic must undergo centralized security inspection and logging.
- Regulatory or contractual requirements mandate centralized control of data flows.
For IT administrators, this explains why performance changes after split tunneling is enabled. It also shows why VPN capacity fills faster than expected and why some security controls no longer apply once traffic leaves the tunnel.
Split tunneling: Security considerations
Split tunneling changes where traffic is inspected and which controls are applied. This directly affects endpoint security in managed environments, making it a crucial part of your VPN routing strategy.
The security risks of split tunneling include:
- Centralized malware filtering and network inspection controls might no longer apply.
- Corporate devices can end up exposed to untrusted networks with little visibility.
- It can cause dual-network exposure, complicating policy enforcement and visibility.
Mitigation strategies include:
- Applying split tunneling only to specific users, roles, or destinations.
- Relying on endpoint security controls to protect traffic outside the VPN.
- Using conditional access policies to restrict access to sensitive applications.
For IT administrators, this means split tunneling should never be treated as a default setting. This requires clear boundaries, strong endpoint controls, and an understanding of which protections are lost when traffic leaves the tunnel.
Align strategy with policy and user experience
Organizations need to decide whether split tunneling fits how employees work, not just how the network is designed. The choice affects security coverage, performance, and how much friction users experience during daily tasks.
Factors to consider:
- How critical is centralized traffic inspection for the organization’s security model?
- Can users regularly access public internet or cloud services while connected to the VPN?
- Can the VPN infrastructure reliably handle all traffic in a full tunnel configuration?
- Which endpoint security controls remain effective when traffic does not pass through the VPN?
VPN split tunneling: additional considerations
- Note that some VPN clients support dynamic split tunneling based on application, destination, or policy.
- Split tunneling behavior varies by VPN client, platform, and provider implementation.
- Performance improvements may not justify the added risk in sensitive or regulated environments.
- Traffic outside the tunnel usually needs separate logging and visibility tools.
Common issues surrounding split tunneling
- Unexpected traffic bypassing controls: Validate the split tunneling policy scope and routing definitions.
- Local traffic is still slow despite split tunneling: Verify local routing paths and confirm DNS resolution is working as expected.
- Policy violations occur: Ensure endpoint controls enforce required protections for off-tunnel traffic.
- User confusion about connectivity: Provide clear documentation for expected routing behavior.
VPN split tunneling should be part of your VPN routing strategy
VPN split tunneling changes how traffic is routed, inspected, and protected whenever devices connect to a remote network. You can use it to reduce VPN load and improve performance, but it also limits how much traffic administrators can inspect and log.
For IT administrators, picking between split tunneling and full tunneling is a policy decision that should be tackled when setting up a VPN. The choice needs to reflect compliance needs, network security posture, and what your infrastructure capacity is. In addition, there needs to be a clear understanding of which protections apply when traffic leaves the tunnel.
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