Split Tunnel vs Full Tunnel VPN: Traffic Paths and Trade-offs

In a full tunnel VPN (virtual private network) configuration, every packet the remote client sends — corporate traffic and general internet browsing alike — is encrypted and routed through the VPN concentrator at headquarters. In a split tunnel configuration, only traffic destined for corporate networks goes through the tunnel; everything else exits directly through the user’s local internet connection. The choice is a routing-policy decision with real consequences for security visibility, bandwidth, and performance, and N10-009 expects you to reason through those trade-offs in scenarios.

What actually decides the path: the client’s routing table

When a VPN client connects, the concentrator pushes routing instructions to the endpoint. Full tunnel installs a default route (0.0.0.0/0) pointing into the virtual tunnel interface, so the operating system sends all outbound traffic through it. Split tunnel instead installs specific routes — say, 10.0.0.0/8 and 172.16.0.0/12 — into the tunnel, leaving the original default route via the user’s home router untouched. A packet for an internal file server matches a tunnel route and gets encrypted to the gateway; a packet for a streaming service matches only the default route and leaves through the local ISP (internet service provider), never touching corporate infrastructure.

That single routing difference drives everything else in this comparison.

Full tunnel: visibility and control at a bandwidth price

Because all traffic transits the corporate gateway, full tunnel puts every packet behind the organization’s security stack: firewall rules, content filtering, IDS/IPS inspection, data loss prevention, and logging apply to remote users exactly as they do in the office. That’s the reason security teams mandate it — when the requirement is “our monitoring and filtering policies must apply to remote workers’ web browsing,” full tunnel is the answer.

The trade-offs:

• Bandwidth consumption at the head end. Every remote user’s video call and software update flows in through the VPN concentrator and back out the corporate internet circuit — a hairpin. Multiply by hundreds of users and the circuit and concentrator become chokepoints.
• Latency for cloud and internet services. Traffic to a nearby cloud service detours through headquarters first, adding round-trip time. Users notice sluggish video conferencing and slow downloads.
• Scalability cost. Concentrator capacity, licensing, and internet bandwidth must all be sized for total remote traffic, not just corporate-bound traffic.

Split tunnel: efficiency with a visibility gap

Split tunneling sends only corporate-destined traffic through the tunnel, so the concentrator and corporate circuit carry a fraction of the load, and users get full-speed local internet for everything else. Video conferencing to cloud services performs notably better because it takes the direct path.

The trade-offs mirror full tunnel’s benefits:

• Loss of inspection. Internet-bound traffic bypasses corporate security controls entirely. If the user’s machine visits a malicious site, the corporate web filter never sees it.
• Simultaneous dual connectivity. The endpoint touches the untrusted internet and the corporate network at the same time. A compromised endpoint can, in principle, be used as a pivot between the two — this is the classic security objection to split tunneling.
• Policy blind spots. Logging and DLP see only the tunneled half of the user’s activity.

A subtlety worth keeping straight for multi-select questions: split tunneling does not weaken the encryption of corporate traffic — tunneled packets are just as protected in either mode. The risk is about what isn’t tunneled, not about the tunnel itself being weaker.

	Full tunnel	Split tunnel
Default route	Through the VPN	Through local ISP
Corporate security controls apply to	All traffic	Only corporate-bound traffic
Concentrator/circuit load	High — carries everything	Low — corporate traffic only
Internet/cloud performance	Slower (hairpin through HQ)	Faster (direct path)
Endpoint bridges two networks at once	No	Yes
Typical driver	Compliance, monitoring, filtering mandates	Bandwidth relief, cloud performance

The split-DNS problem

Routing is only half the story — name resolution has its own path. Internal hostnames like intranet.corp.local exist only on corporate DNS (Domain Name System) servers. Under split tunneling, if the client keeps using its local resolver (the home router or public DNS), queries for internal names either fail outright or, worse, leak internal hostnames to an outside resolver. The concern is real in both directions: broken access to internal apps, and information disclosure about your internal namespace.

The mitigation is client DNS configuration pushed at connect time: the VPN assigns corporate DNS servers and, in a proper split-DNS setup, defines the internal domain suffixes whose queries must go through the tunnel to corporate resolvers while all other lookups stay local. Verifying which resolver a connected client actually uses is a standard troubleshooting step when a remote user reports “the intranet won’t load but the internet works” — that symptom pattern on a split tunnel almost always points at DNS, not routing.

Choosing and configuring in practice

Most organizations land on a policy split: full tunnel for high-security roles or compliance-scoped users, split tunnel for the general population with compensating endpoint controls (host-based firewall, EDR, DNS filtering on the client). Whichever mode you run, document the pushed routes and DNS settings — the majority of remote-access tickets trace back to a destination that isn’t in the tunnel’s route list or a resolver mismatch. These modes apply to client-to-site connections; for how that VPN type compares with clientless access, see client-to-site and clientless VPNs.

How the N10-009 exam tests this

• “With split tunneling enabled, what happens to internet-bound traffic?” — it exits directly via the user’s local internet connection, bypassing the corporate network. Distractors claim it’s dropped, or encrypted to HQ anyway.
• Security team wants all remote traffic, including web browsing, subject to corporate filtering/monitoring — choose full tunnel, and expect the follow-on trade-off: increased load on the VPN concentrator and corporate internet circuit, plus added latency for users.
• Two-answer trade-off questions — credited pairs typically state that full tunnel applies corporate inspection to all traffic, and that split tunnel leaves internet-bound traffic outside corporate controls (or that the endpoint is connected to both networks simultaneously). Wrong options claim split tunneling weakens the tunnel’s encryption.
• Internal hostnames failing to resolve on a split tunnel — recognize the split-DNS issue and its fix: push corporate DNS servers/suffix rules through the VPN so internal-domain queries go to internal resolvers.

Trade-off questions are easiest to learn by answering them — the practice exam bank covers every framing above.

VPN scenarios like these sit in the Network Operations domain — the N10-009 study guide maps them into a full prep plan.

Quick reference

• Full tunnel = default route through the VPN; split tunnel = only defined corporate routes tunneled.
• Split tunnel internet traffic goes straight out the local ISP — no corporate inspection, filtering, or logging.
• Full tunnel enforces policy on everything but hairpins all traffic through the concentrator: more bandwidth, more latency.
• Split tunnel risk framing: endpoint bridges untrusted internet and corporate network simultaneously.
• Encryption strength of tunneled traffic is identical in both modes.
• Internal-only hostnames need corporate DNS pushed via the VPN (split DNS) or they break/leak on split tunnels.
• “Intranet down, internet fine” on a split tunnel → check which DNS resolver the client is using.