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Network Security: What is it and how does it work?

Written by Alexander Chapellin | May 12, 2025 8:15:49 PM

Did you know that a poorly protected network can put your entire company at risk without you even realizing it? Sometimes all it takes is a weak password, a misconfiguration or a simple click on a suspicious link for the problems to start. And the most worrying thing is that many times you don't even notice that something is wrong... until it's too late. In this article we'll explain what network security is, why you should take it seriously and what you can do to avoid leaving the door open to the risks that are out there. You will learn how to protect your company using key tools such as VPNs, firewalls, and much more.

 

Table of Contents

 

 

What is network security?

 

Network security is basically everything we do (whether with tools, processes or rules) to protect a person's or company's digital information and systems. Protect them from what? From threats that seek to steal data, damage equipment or get in where they shouldn't be.

In short, it's about keeping everything that passes through your network safe: emails, files, access to systems... ensuring that only people with permission can see or use that information, and blocking those who come with bad intentions.

And why would someone want to attack a network? The most common reasons are to steal data, impersonate, manipulate information, or simply bring down a system. And yes, these things happen more often than you might imagine.

 

Are network security and cybersecurity the same thing?

 

They look alike, but they're not exactly the same. Cybersecurity covers everything related to protecting information and systems in the digital world. Within that, network security focuses on taking care of everything that goes on inside your business network, as if it were a castle wall.

Inside that “castle” are the servers, computers, routers, databases and all the equipment you use every day. Network security makes sure that only those who should get in, get in, and that the rest stays out.

 

 

How does network security work?

 

It works by setting filters and controls that decide who gets in, what they can do, and what is blocked. First the user's identity is checked (like when you enter your username and password), and then access is given depending on what they are allowed to do. It also takes care of detecting strange movements and curbing those who shouldn't be there. All this works in layers, like an onion: the more layers, the harder it is for someone to get through. There are key concepts you need to know to start protecting your network effectively.

 

Access control

 

This is the system that decides who enters the network and what they can do there. You've probably already used it without realizing it: when you log on to your laptop or system with a username and password, you are going through access control. This process has four steps:

 

  1. Identification: knowing who you are (your username, email or account number).

  2. Authentication: verify that it is really you (with your password or verification).

  3. Authorization: define what you can access or what you can do.

  4. Accountability: record your actions, in case you have to check later who did what.

 

Network segmentation

 

Imagine dividing your network into “rooms” instead of having everything mixed in the same room. This way you can put more security on important areas and have everything more organized. A common way to do this is with VLANs (virtual networks within the physical network). And if you use cloud services, they are called VPCs (virtual private clouds). This helps to have more control and prevent a problem from spreading throughout the network.

 

Perimeter security

 

In a traditional network, the “perimeter” is like the border between what is inside your company and what is outside (Internet). That boundary is protected with tools that decide what can get in and what can't.

Some examples:

 

  1. Firewalls: block or allow traffic according to rules.

  2. IDS (intrusion detection system): detects suspicious behavior.

  3. IPS (intrusion prevention system): not only detects, but also acts to stop the problem.

 

All this is configured according to your needs: what kind of data you let through, what you block, what you monitor.

 

Read more: Firewall Explained: How It Works and Why It Matters

 

Data Encryption

 

Encryption is like putting a lock on your data: if you don't have the key, you can't read anything. It's a super useful way to protect data, either when you're sending it or when it's stored. There are two main types:

 

  1. Symmetric encryption: uses a single key to encrypt and decrypt. It is fast and is widely used for things like banking sessions.

  2. Asymmetric encryption: uses two keys, one public and one private. It is more secure for exchanging keys, although a bit slower.

 

For example, when you log into your bank's website, symmetric encryption is used to protect what you do, and asymmetric encryption is used to verify that the site is authentic and no one is impersonating it.

 

Why should you take this seriously?

 

Because believe it or not, any network (no matter how small) can be the target of a cyberattack. Nowadays, even a camera connected to the Internet can be a gateway. And many times, the most common mistakes (like using easy passwords or opening a booby-trapped email) are the ones that open the door the most.

The good news is that there are very practical and accessible ways to protect yourself. By knowing the basics and using the right tools, you can greatly reduce your risk.

 

Read more: Who responds to the first cyber attack? Few Companies Know

 

Types of Network Security

 

Not all networks are the same, nor are all threats addressed with the same solution. That is why there are different types of network security, each with its own advantages and objectives. The ideal is to analyze your company's needs (for example, by performing a pentest or penetration test) to find out which combination suits you best. Here we explain the most common ones:

 

Firewalls

 

They are like the gatekeepers of your network. A firewall, whether it is a program or a physical device, checks everything that wants to enter or leave your network and decides whether to let it pass or not. Basically, it blocks what it sees as suspicious and lets through what it has permission to.

There are several types: from the most basic ones, such as packet filtering, to the most advanced ones that use artificial intelligence to analyze traffic. There are even new generation firewalls that “learn” to recognize strange behavior.

 

Intrusion detection and prevention systems (IDPS)

 

An IDPS is like having an extra guard behind the firewall. Its job is to detect if something strange has already made it past the first filter and, if necessary, block it, send an alert or even close the connection completely. There are more passive versions (they only warn) and more active ones that react automatically. They serve as an additional layer of defense so that nothing sneaks in unnoticed.

 

Antivirus and antimalware

 

The classic that cannot be missed. There is malware of all kinds: viruses, Trojans, ransomware, spyware.... Some hide so well that they can go undetected for days. That's why modern antivirus programs not only scan for known viruses, but also monitor file and system behavior, remove new threats and, if necessary, repair the damage caused.

 

Network Access Control (NAC)

 

This is the gateway filter. Before any device connects to your network, the NAC checks that everything is in order: active antivirus, up-to-date system, correct settings, etc. You can also configure it to give access according to the user's profile. For example, someone from the administrative area should not be able to access the servers of the technical area. This way you make sure that everyone only sees what they are allowed to see.

 

Security in the cloud

 

Today almost everything is in the cloud: files, emails, apps, services. And of course, you also have to protect all of this. To achieve this, several tools are combined, such as firewalls, encryption, access controls, VPNs and disaster recovery plans. The most important thing here is to have clear policies and not to take for granted that “because it is in the cloud it is already secure”.

 

VPN (Virtual Private Network)

 

A VPN hides your IP and your location, connecting you first to a secure server before going out to the Internet. It's like putting a private tunnel on your connection. It is very useful if you work from home or use public WiFi (cafes, airports, coworkings), because it prevents someone else on the network from spying on you or stealing your data.

 

Data Loss Prevention (DLP)

 

DLP focuses on protecting sensitive information, especially when it leaves the company environment. For example, if someone tries to mail a database with credit card information or medical records, this system detects it and acts: it blocks, warns or encrypts the info. It is widely used by companies that handle data regulated by legal or privacy standards. 

 

Endpoint security

 

Here we talk about protecting all the devices that connect to your network: computers, laptops, tablets, cell phones, etc. Each of these “endpoints” is a possible entry point for an attack. Endpoint security uses tools that monitor and protect each device, preventing malware from entering the network through them.

 

Read mor: Threat Detection and Response with TecnetProtect

 

Unified Threat Management (UTM)

 

If you want to have everything in one place, UTM is for you. They are devices or systems that combine several security functions in a single platform: firewall, VPN, intrusion detection, antivirus, etc.

This helps you have better control without having to manage many separate tools. Ideal for small or medium-sized companies that want a practical and complete solution.

 

Secure Web Gateway (SWG)

 

The SWG acts as an intermediary between you and the Internet. Its function is to check all web traffic before it reaches your internal network. If something looks suspicious, it blocks it or “emulates” it (tests it in a secure environment) before letting it through. It helps protect you against malicious web pages, dangerous downloads and any attempt to sneak malware through your browser.

In short, network security is not just about installing an antivirus and forgetting about it. It's a whole ecosystem that, when properly armed, protects your company on all fronts. Not all the tools are for everyone, but the important thing is to know them and to know which one to apply according to your case.

 

Where are the weak points in network security?

 

Although it may not seem like it, there are parts of a network that are more fragile than others and, if you do not take good care of them, they become an open door for cyber-attacks. Here we tell you which areas to pay special attention to:

 

  1. File sharing is always risky. Whether by mail, USB or in the cloud, you never know if a file comes clean or with a surprise (read: malware).

  2. Email is a favorite of attackers - have you heard of phishing? It's when someone impersonates a trustworthy company or person to steal information from you or sneak a virus in an attachment or link.

  3. Having outdated programs, operating systems or software is like leaving the door ajar. Old versions often have bugs or holes that attackers already know about and know how to exploit.

  4. Files with hidden extensions that look harmless, but are not. If a file looks strange, don't open it. It is better to be safe than sorry.

  5. Messaging platforms or chatbots can also be a risk. Some links or files they send may look safe, but may contain malware. And beware of giving personal data to someone who writes to you “on behalf of the bank” or “technical support”, because they may not even be real.

  6. WiFi networks are more vulnerable than wired ones. If you don't protect them well, anyone nearby could connect and snoop what is going on inside your network.

 

Why is network monitoring so important?

 

Nowadays cyber-attacks are everywhere. It is no longer a thing of movies or giant companies; it can happen to anyone. From someone working freelance at home to a company with hundreds of employees. And yes, the impact can be serious: from losing money to damaging the reputation of your business.

That's why it's key to have a good cybersecurity strategy. At TecnetOne, for example, we offer a SOC: SOC as a Service, a service designed for just that: to help you keep your network and devices well protected, and to support you if you need to comply with international certifications.

Of course, this is not solved with a single click. Security is built little by little. The first thing is to decide that yes, it is worth taking care of your privacy (even if nothing has ever happened to you). Then you add it up: update your computers, use a good antimalware, connect via VPN, check who has access to what... every step helps.

Think of it like guarding your home: if you leave the door open or a window unlocked, anyone can get in. But if you lock everything, install an alarm and you're on the lookout, you'll be able to rest easy knowing you did what you needed to do.

At TecnetOne we protect the most valuable thing: your information. Our team at the SOC (Security Operations Center) works 24/7 to reduce risks, detect threats and keep your network safe.
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