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Network Devices

Updated Jan 16, 2018 ·

Network Hubs​

Hubs are basic networking devices that broadcast data to all connected devices without distinguishing between them.

  • Connect multiple devices in a network, commonly found in home networks
  • Less intelligent compared to switches or routers

With a network hub, all network traffic is always flooded to all hub ports; it is a single broadcast domain and cannot be configured otherwise

Network Bridges​

A network bridge is a device that connects two or more network segments, allowing them to function as a single network.

  • Each segment becomes its own collision domain
  • Filters and forwards traffic based on MAC addresses.
  • Does not route packets between different networks or broadcast domains

A bridge can be used to create network segments, or collision domains, but it cannot create multiple broadcast domains.

Switches​

Switches are networking devices that connect multiple devices within a local area network (LAN).

  • They direct data between devices within the network
  • Typically hidden in wiring closets
  • Each switch port connects to one end of a network cable

The cables run through conduits, connecting to Ethernet jacks (wall jacks) throughout the building.

WAPs​

Some devices connect to the network wirelessly via Wireless Access Points (WAPs). These WAPs are connected to switches and create Wi-Fi networks, sending and receiving signals to and from mobile devices.

For more information, please see WAPs.

Dual-Homed​

Dual-homed devices are devices which have at least two network interfaces, each on a different network or segment....

  • Bridges
  • Routers
  • Firewalls
  • Gateways
  • Some proxies

(ISC)² and CompTIA often refer to screened-host firewalls or bastion hosts as the classic dual-homed devices because they intentionally sit between two networks with separate NICs for isolation.

Routers​

Routers are devices that direct data between different networks, ensuring it reaches its correct destination.

  • They connect LANs to the internet or other networks
  • They determine the best path for data to travel across networks
  • They often include firewall and network management features

Router Planes​

A router operates using three main functional planes:

  • Management Plane

    • Handles traffic destined for the router itself
    • Protocols: SSH, SNMP

  • Control Plane

    • Manages the network infrastructure and routing decisions
    • Processes data in software
    • Protocols: OSPF, BGP, EIGRP

  • Data Plane

    • Forwards packets using information from the control plane
    • Responsible for high-speed packet switching
    • Processes data in hardware

Core Routers​

Core routers act as the core of your network communication. They handle high-volume data packets and enable forwarding between the connected networks. They do not communicate with the external world, such as the internet.

Servers​

Servers are powerful computers that manage and deliver resources or services to other devices on a network.

  • Provides information to other computers on a network
  • Common types include web servers, email servers, print servers, database servers, and file servers
  • Secured differently than workstations

Endpoints​

Endpoints are the devices that act as the source or destination of network communication.

  • Ends of a network communication link
  • One end often at a server with a resource, the other end a client making a request
  • Can be servers, desktops, laptops, tablets, mobile phones, or other end-user devices

Network Sensors​

Network sensors are devices that continuously monitor network traffic to identify and report on anomalies and potential security threats.

  • Devices or software agents deployed within a network
  • Collect data for analysis and reporting
  • Integrate with other security systems to automate alerts and responses

Types of Network Sensors:

  • Intrusion Detection Systems (IDS) Passive sensors that alert when threats are detected.

  • Intrusion Prevention Systems (IPS) Active sensors that can also block traffic.

  • Flow Sensors Monitor metadata (e.g., NetFlow, sFlow) instead of full packet contents.

  • Packet Capture (PCAP) Sensors Collect full packet data for in-depth analysis.

Jump Servers​

Jump servers, also known as "jump boxes," provide a secure and controlled environment for administrators to perform network tasks.

  • Serve as secure access points for admin tasks
  • Isolate administrative activities from regular network traffic
  • Log and monitor all administrative actions for auditing purposes
  • Usually host a range of tools and scripts for system administrators

Firewalls​

Firewalls are security devices that monitor and control network traffic based on predefined rules.

  • They block or allow traffic to protect networks from unauthorized access
  • Firewalls can filter both inbound and outbound traffic

For more information, please see Firewalls.