computer science

Split tunneling

Split tunneling is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Split tunneling rather than just read about it. In short: In computer networking, split tunneling allows a user to access distinct security domains at the same time, using the same or different network connections. This connection state is usually facilitated through the simultaneous use of a LAN network interface controller (NIC), radio NIC, Wireless LAN NIC, and virtual private network client software application.

Key takeaways

Split tunneling belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Split tunneling to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Split tunneling from memory before moving on to harder problems.

Reference excerpt

In computer networking, split tunneling allows a user to access distinct security domains at the same time, using the same or different network connections. This connection state is usually facilitated through the simultaneous use of a LAN network interface controller (NIC), radio NIC, Wireless LAN NIC, and virtual private network client software application. Split tunneling is most commonly configured via the use of a remote-access VPN client, which allows the user to simultaneously connect to a nearby wireless network, resources on an off-site corporate network, as well as websites over the internet. A split tunnel configured to only tunnel traffic destined to a specific set of destinations is called a split-include tunnel. When configured to accept all traffic except traffic destined to a specific set of destinations, it is called a split-exclude tunnel. Not every VPN allows split tunneling. Advantages of split tunneling include alleviating bottlenecks, conserving bandwidth (as internet traffic does not have to pass through the VPN server), and enabling a user to not have to continually connect and disconnect when remotely accessing resources.. Disadvantages include potentially bypassing gateway-level security that might be in place within the company infrastructure. Internet service providers often use split tunneling to that implement for DNS hijacking purposes.

Variants and related technology

Inverse split tunneling An "inverse" split tunnel is one that allows all datagrams to enter the tunnel, except those destination IPs explicitly allowed by VPN gateway. The criteria for allowing datagrams to exit the local network interface (outside the tunnel) may vary from vendor to vendor. This keeps control of network gateways to a centralized policy device such as the VPN terminator. This can be augmented by endpoint policy enforcement technologies such as an interface firewall on the endpoint device's network interface driver, group policy object or anti-malware agent. This is related in many ways to network access control (NAC).

Dynamic split tunneling A form of split-tunneling that derives the IP addresses to include/exclude at runtime-based on a list of hostname rules/policies.

IPv6 dual-stack networking Internal IPv6 content can be hosted and presented to sites via a unique local address range at the VPN level, while external IPv4 & IPv6 content can be accessed via site routers.

References

Further reading Juniper(r) Networks Secure Access SSL VPN Configuration Guide, By Rob Cameron, Neil R. Wyler, 2011, ISBN 9780080556635, P. 241 Citrix Access Suite 4 Advanced Concepts: The Official Guide, 2/E, By Steve Kaplan, Andy Jones, 2006, ISBN 9780071501743, McGraw-Hill Education Microsoft Forefront Uag 2010 Administrator's Handbook, By Erez Ben-Ari, Ran Dolev, 2011, ISBN 9781849681636, Packt Publishing Cisco ASA Configuration By Richard Deal, 2009, page 413, ISBN 9780071622684 , McGraw-Hill Education

External links

"Split Tunneling in Linux". Archived from the original on November 5, 2024. Split Tunneling in 2025

Worked examples

Example 1 — a first encounter with Split tunneling

Start with the simplest possible case. Write down what Split tunneling claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Split tunneling before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Split tunneling ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Split tunneling

In research: Split tunneling appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Split tunneling in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Split tunneling is common in secondary-school and first-year university syllabi. It links to neighbouring topics Computer network security, Internet privacy, Network architecture, so understanding it makes those chapters shorter.
In everyday life: Look for Split tunneling outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Split tunneling in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Split tunneling means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Split tunneling out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Split tunneling in simple terms?

Why does Split tunneling matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Split tunneling?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Split tunneling.