ccna-notes

Network Devices

Table of contents

• Network
• Server
• Client
• Switches
• Routers
• Firewalls

Network

A computer network is a digital telecommunications network which allows nodes to share resources

Server

Device that provides functions or services for clients

Client

Device that accesses a service made available by a server

Switches

You typically don’t connect end-hosts or PCs directly to each other, you aggregate the connections to a device called a “switch”.

• have many network interfaces/ports for end hosts to connect to (usually 24+)
• provide connectivity to hosts within the same LAN (Local Area Network)
• do not provide connectivity between LANs or over the internet

Routers

We can connect switches to routers to connect to the internet.

• have fewer network interfaces/ports than switches
• are used to provide connectivity between LANs
• used to send data over the internet

Firewalls

There are potential “attackers” in the internet. Although router can provide some basic security features, what we should use to protect our networks are firewalls.

• monitor and control network traffic based on configured rules
• can be placed outside of your LAN (filter traffic before reaching the router)
• can be placed inside of your LAN (filter traffic after going through the router)
• are considered “Next-Gen” when they include more modern and advanced filtering capabilities

Host-based firewalls

These are software applications that filter traffic entering and exiting a host machine (like a PC). Even in a network with a hardware firewall each PC should include a software firewall for an extra protection layer.