What is network security?

Network security is a set of measures, technologies, and rules that protect computer networks and the data transmitted through them from unauthorized access, attacks, and failures.

In simpler terms: network security exists so attackers cannot get into the network, and data cannot be stolen, tampered with, or used to disrupt the system.

Why network security is needed

Modern networks are constantly connected to the internet, which means:

• they can be hacked,
• data can be intercepted,
• services can be taken down (for example, by DDoS attacks).

Network security helps:

• protect confidential data (passwords, personal information),
• keep the network running reliably,
• prevent financial and reputational losses.

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#What network security actually protects

#1. Data

So that it is not:

• stolen,
• altered,
• intercepted in transit.

#2. Devices

• servers,
• computers,
• routers,
• network equipment.

#3. Users

So attackers cannot gain access under someone else's account.

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#Main network threats

This is often asked in interviews.

• Hacking (unauthorized access)
• Malware (viruses, trojans)
• Traffic interception (sniffing)
• DDoS attacks (overloading a service)
• Phishing (deceiving users)

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#Main network security tools

#Firewalls

Filter incoming and outgoing traffic: decide what to let through and what not to.

#Encryption

Makes data unreadable to outsiders (for example, HTTPS, VPN).

#Authentication and authorization

Verify:

• who you are (authentication),
• what you're allowed to do (authorization).

#Intrusion detection systems

Monitor suspicious activity on the network.