Computer networks, those that connect computers to each other and allow our PCs and mobile phones to connect to the internet and browse websites, are now quite simple to configure, even if there is enormous complexity behind it. The intention of this guide to LAN, Wifi and internet connection is not, however, to provide a manual to pass the exam at the university, but much more humbly to provide a vademecum with the most important notions not only to understand something more theoretically, but above all to understand how connections are made and how to solve any connectivity problems that may arise.
Having already written numerous articles about it, we can consider this as a great guide on the home computer network and on the internet, a summary or a first page from which to find more accurate instructions on each aspect.
READ ALSO: Computer dictionary for the Internet and Networks with the meaning of the main terms
1) The device for internet access today is the router
Even if it is possible to surf the internet without a router, through direct computer access to the modem, it is not possible to create a LAN or a Wifi network without a router.
In this regard it is important to know the differences between routers and modems and above all to understand what a router really does.
In summary, the modem is that device that connects to the internet, that is, to the entire network of devices that manage websites and applications.
The router, on the other hand, is used to direct the data received from the outside to the right computer.
In other words, if the modem is the door to leave the house, the router is instead like a policeman who tells the data to go one way or the other.
Usually the router and modem are in the same appliance that we have at home, the one with the lights that connects to the wall to the telephone socket.
2) How network devices communicate on the internet
From a theoretical point of view, the data that is sent and received from a computer via the internet is managed by the TCP / IP protocol.
We explained how this works in the guide on how TCP / IP works and how computers on a network speak.
In general, while the Transmission Control Protocol (TCP) is responsible for breaking down data into small packets and recomposing them, the Internet Protocol (IP) instead manages the travel of packets, so that they are received by the right recipient.
In another article we also talked about the difference between TCP and UDP.
3) IP addresses
Networked computers are identified by an IP address.
The IP address is like the machine plate, an identification number within the network.
Each PC has an internal IP, the one assigned by the router to distinguish one PC from another in the home and an external IP, the one that is instead assigned to the modem, with which all the home PCs are recognized on the internet.
Internet connection requests are made by the external IP, which can be variable or static depending on what is offered by the connection provider (i.e. by Fastweb or Telecom or other companies).
The internal IP, on the other hand, is useful for making home computers communicate with each other and transferring data.
These dynamics can be explored in the following articles:
- Who can see our IP address and what can it do "> Why do computers at home have an IP address of type 192.168.XX?
- How do we connect to the internet and why with the same Public IP?
- Find public IP and private IP and difference
- Find the IP of the router
4) DNS server
Speaking of the internet, it is important to know what DNS means.
A website is nothing more than a set of files, documents, images and much more, which are stored in a computer, called a web server, connected to the internet with a fixed IP address.
DNS servers are lists that associate the IP addresses of websites with names that are easy to remember, like in a telephone directory.
These servers, located all over the world, allow us to identify the IP of the computer (the server) where the google.com or navigaweb.net site is located without the need for us to remember it.
In this regard, we have seen several guides, including the one to change DNS on PC, Mac and router quickly.
5) The internet
By putting this type of information together we should have a clear idea of the general scheme of the huge internet network, where every website is hosted by a computer (which is the server) and has an IP address, just like every other computer in the world.
My PC, when connected to the Navigaweb.net site, makes a DNS request to the network provider (the one to which I pay the subscription), which associates an IP address with the name www.navigaweb.net.
Once the server hosting the site I have requested is recognized, it allows you to download the data and present the web page with images, text and code on my computer.
In the same way, from my smartphone I can connect to the Whatsapp network, by accessing the server that manages the service or other applications such as Facebook and Skype.
6) The connections of a home network (LAN)
Going back to the home LAN, we see that computers can be connected to the router / modem in two different ways, via Ethernet cable or wirelessly via wifi, wirelessly.
Different computers connected to each other through the router can talk to each other and exchange data and resources as we will see in point 10.
Smartphones, however, must necessarily connect to wifi, because they do not have an ethernet port.
On this, we explained in another article which connection is better between ethernet and wifi and the difference between different ethernet cables.
Regarding the wifi, however, we have seen the difference between 2.4 GHz and 5 GHz Wi-Fi networks and the difference between 802.11ac or 802.11n routers.
NOTE: The connection to the network can also take place through the electrical network, through devices called Powerline.
7) Wifi Router and network security configurations
The wifi networks are absolutely more comfortable than the cable ones, especially for the smaller footprint and the possibility of connecting different devices such as smartphones, the TV; the alarm.
The only problem with Wifi is that it requires configuration and, above all, safety measures to prevent anyone passing by from connecting and entering our computer network.
In this blog we wrote how to configure a wifi router safely and what are the most important options to modify on the router.
From a network security point of view, it is also worth knowing the firewall function integrated in most routers and the possibility of installing a firewall on the PC to prevent unauthorized connections from the outside.
8) Amplify wifi network
As explained in another guide, there are several ways to amplify the wifi signal of a wireless network, using repeaters, using two or more routers or even through the powerplugs I mentioned in point 6.
9) Ports and port forwarding configurations
If particular connections are used, for example to play online or to use Peer-to-peer programs or even to allow remote connections to our computer, it may be necessary to configure port forwarding.
Ports are the network addresses of the programs and are represented by a number.
Just to understand, if from the outside I can connect to a computer using the IP address, but this is not enough, because we have to connect to a program.
This can be the remote desktop program or the program that manages the transfer of files or even the program that runs a webserver and therefore manages the publication of a website.
The ports, for security reason, are closed by routers and require to be opened manually if particular programs are used.
On this, we saw the guide on how to forward / open ports on the Router.
10) Remote desktop and file transfer
Two of the best advantages of LANs, corporate or home, are the connection in remote desktop from one PC to another and the free transfer of files or the sharing of folders and printers.
Regarding the remote desktop, we have seen in another article the best solutions for the remote control of the PC
As for the file transfer, however, we have the guides to share files and folders on the network and how to configure a network printer.
11) Solving network problems
If something does not work properly, in other guides we have several ideas to solve each problem:
- Solutions of wifi and router connection problems
- If the PC does not connect to the internet, restore the network and web browsing
- How to solve internet connection problems
- Solutions to problems on internet connection and wireless networks
