1. Introduction to Computers
Network Devices

2. Servers
Servers are hosts on the network that provide a service. This service may be facilitating networking (like a DHCP or DNS server) or it may be the reason we are connecting to the network (like an FTP or web server)
We call both the device providing the service and the actual service itself a server. This is important, because one device may provide multiple services. For example, one computer may be both a DHCP server and a DNS server.
When we implement our network services like that, we can use software to take down the services individually and maintain them without interrupting the other services. Although if we disconnect, turn off or perform maintenance on the hardware itself, it will take down all services the box offers

3. Server Types (1)
There are many different kinds of server, and it is a good idea to be aware of what they are. We are only going to be discussing a few types
File and Print Servers
File and print servers provide file sharing on a network. They allow other hosts to store and access files across the network. They also process network print jobs
Application Servers
Application servers provide some sort of network application that can be used by hosts on a network. One common implementation is a database server, where hosts can read and write information to a network database. Another example would be the servers that provide Netflix

4. Server Types (2) Directory Server Remote Access Server Web Server
A directory server handles user authentication and information. Directory servers store user information, authentication information, user permissions, and user settings
Remote Access Server
A remote access servers provide remote access to a work station within a network. For example if an employee is working from home, they can use a remote access server to connect to the work station and use internal network services
Web Server
Web servers are probably one of the most prolific types of servers. Web servers are used to provide websites via HTTP. Anytime you use the Internet and access a webpage, you are accessing a web server

5. Servers Providing Network Functions
DNS Server
A DNS server doesn’t provide a function in the same way as a web server or an application server. Instead, a DNS server facilitates connection to other servers. The job of a DNS server is to map IP addresses to domain names. Remembering a domain name is a lot easier than an IP address. For example it's a lot easier to remember TestOut.com than the IP address associated with the web server
DHCP Server
A DHCP server is used to automatically configure hosts that connect to a network. Every host that connects to a network needs to be assigned a unique IP address, a subnet mask, a DNS server address, and a default gateway address. While we could manually configure all of that, a DHCP server is implemented which automatically configures each host that connects to the network with the required information. This is done by sending a series of DHCP messages that include all the necessary information

6. VoIP
Another use for networks is VoIP (Voice Over IP). VOIP is when we connect phones or other communication devices like webcams onto a network in order to send and receive voice communication
VoIP phones have an RJ45 connection instead of an RJ11 connection, as well as a converter in order to convert voice into digital data and back into voice
One very common example of VoIP is Skype. The main thing to remember about VoIP is that it connects to the network using an Ethernet connection and uses an IP network instead of the traditional telephone network.

7. Internet Appliances
Internet appliances are devices that provide a simplified method of network management and control. They are designed to be able to be plugged into a network and provide the designated service with minimal configuration or knowledge
For example -
A web proxy appliance will create an intermediary between you and the servers you are accessing for privacy reasons,
A content filter can be configured to block specific types of content, like inappropriate websites
A malware scanner is able to scan incoming s for malicious applications or files
Please note that most of these services can be implemented more cheaply on a physical server system, but a dedicated appliance will typically perform better and be easier to setup and use

8. NAS
The last network device we're going to talk about is similar to a file server, but is much more efficient. Network-attached storage (NAS) devices are a dedicated file server device
Their only job is to provide storage and share network files, that's it. Because their role is so specific, NAS devices are much easier to configure, set up, and manage than a traditional file server
Basically all you have to do is plug a NAS into your network, make minimal configurations and then NAS is up and running and ready to serve files in the server extremely fast. Even though some NAS devices are extremely expensive, they are much more efficient and provide more functionality than a traditional file server

9. Internet of Things
A growing sector of the internet is the “Internet of Things”
Cell phones and devices like Amazon Alexa and Google Home are making it easier to access the internet of things
This is the concept of connecting traditionally un-networked electronics (light bulbs, outlets, coffee makers, watches, refrigerators, etc) to a network
This has the capability to provide a lot of new services and features to devices. For example,
A connected refrigerator can send a message to your phone to create a shopping list
A connected light bulb can be turned on and off by your phone to create the illusion that someone is home and deter robbery
A connected thermostat can upload usage statistics that can be used to help budgeting