# middlebox

> intermediary box performing functions apart from normal, standard functions of an IP router on the data path between a source host and destination host

**Wikidata**: [Q6841716](https://www.wikidata.org/wiki/Q6841716)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Middlebox)  
**Source**: https://4ort.xyz/entity/middlebox

## Summary
A **middlebox** is an intermediary box on the network data path between a source host and a destination host. It performs functions **beyond the normal, standard functions of an IP router**. Middleboxes are considered both **computer appliances** and **networking hardware**.

## Key Facts
- A middlebox is an **intermediary box** located on the data path between a **source host** and a **destination host**.
- It performs functions **apart from** the normal, standard functions of an **IP router**.
- Middlebox is classified as a subclass of **computer appliance**.
- Middlebox is classified as a subclass of **networking hardware**.
- Known aliases include **ミドルボックス** and **中间件**.
- The Wikidata description defines it as: “intermediary box performing functions apart from normal, standard functions of an IP router on the data path between a source host and destination host.”
- The Wikipedia title for the concept is **“Middlebox”**.
- Wikipedia language editions listed for this topic include **English (en)** and **Japanese (ja)**.
- Identifiers include **Freebase ID: /m/091cqq** and **Microsoft Academic ID (discontinued): 2780584376**.

## FAQs
### Q: What is a middlebox in networking?
A: A middlebox is an intermediary box placed on the data path between a source host and a destination host. It performs functions beyond the normal, standard functions of an IP router.

### Q: How is a middlebox different from an IP router?
A: An IP router performs standard routing functions. A middlebox sits on the same data path but performs functions **apart from** those normal, standard router functions.

### Q: Is a middlebox hardware or software?
A: In this context, a middlebox is described as a **box** and is classified as both **networking hardware** and a **computer appliance**. That implies a dedicated device providing specific network-related functions.

### Q: What categories does “middlebox” belong to?
A: Middlebox is a subclass of **computer appliance** and **networking hardware**. These categories frame it as a single-purpose device used within computer networks.

## Why It Matters
Middleboxes matter because they represent a class of network devices that do more than basic IP routing while still operating directly on the traffic path between communicating hosts. By sitting between a source host and a destination host, a middlebox can affect how data flows through a network in ways that a standard router does not. This makes the concept important for understanding real-world network behavior, since not all traffic is handled solely by endpoints and routers. The classification of middleboxes as both computer appliances and networking hardware highlights that they are typically dedicated devices designed to provide specific network-related capabilities. For practitioners and researchers, the term “middlebox” provides a concise way to refer to these intermediary devices and to distinguish their non-standard routing functions from conventional IP routing. In short, the concept is central to describing networks where intermediary devices actively perform additional functions on in-transit traffic.

## Notable For
- Being explicitly defined as an **intermediary box** on the data path between a source host and destination host.
- Performing functions **beyond** the normal, standard functions of an **IP router**.
- Being classified simultaneously as **networking hardware** and a **computer appliance**.
- Having multilingual aliases, including **ミドルボックス** and **中间件**.
- Having recognized identifiers across knowledge bases (e.g., **Freebase** and **Microsoft Academic**).

## Body
### Definition
- A **middlebox** is an intermediary box on the network data path.
- It is positioned between:
  - a **source host**, and
  - a **destination host**.
- It performs functions **apart from** the normal, standard functions of an **IP router**.

### Placement in a Network
- Middleboxes operate **on the data path** between communicating hosts.
- Their defining characteristic is **intermediary placement** rather than being an endpoint.

### Classification
- **Subclass of: computer appliance**
  - A computer appliance is a single-purpose computing device with software or firmware dedicated to providing a specific computing resource.
- **Subclass of: networking hardware**
  - Networking hardware includes devices that mediate data in a computer network.

### Names and Identifiers
- **Aliases:** ミドルボックス, 中间件
- **Freebase ID:** /m/091cqq
- **Microsoft Academic ID (discontinued):** 2780584376
- **Wikipedia title:** Middlebox
- **Wikipedia languages:** en, ja