What is network security?

23 July 2021

8 minutes

Authors

Mesh Flinders

Author, IBM Think

Ian Smalley

Senior Editorial Strategist

What is network security?

Network security is a field of cybersecurity that’s focused on protecting computer networks and communication systems from internal and external cyberthreats and cyberattacks.

Today, computer networks form the backbone of most modern enterprises, from employee communication and collaboration tools to complex applications (apps), cloud-native business operations, and even global infrastructure. Modern networks and the tools and solutions that keep them safe, are critical to the success of some of the largest and most successful companies in the world.

According to a recent report, the global market for network security solutions is substantial and growing at a healthy rate. In 2024, it was worth USD 24 billion and is expected to continue to grow at a compound annual growth rate (CAGR) of 14% to reach USD 73 billion by 2032.1

What is a computer network?

Computer networks, or just networks, are systems of interconnected devices that communicate with each other, share data and exchange resources. Devices connected through a network use various connections, including Ethernet, wireless (wifi) and cellular. After establishing a connection, they must follow a set of rules known as communication protocols that govern how they exchange data. Common devices used in computer networking include desktops, mobile devices and routers.

Today, computer networks underpin almost every aspect of daily life, from empowering the mobile workforce to underpinning social networks and powering the global financial system. When they are breached, it is expensive. 

According to the IIBM Cost of a Data Breach 2024 Report, the global average cost of a data breach was USD 4.9 million last year. This increase marks a 10% rise over the previous year and represents the highest total ever recorded.

What is cloud computing?

Like all other aspects of IT infrastructurecloud computing has fundamentally changed networks. It replaces hardware-based, on-premises network infrastructure with virtualized, on-demand compute resources delivered over the internet.

Until the early 2000s, enterprises favored on-premises IT infrastructure, hardware and software that could be kept in a facility the company owned and operated. But the benefits of the cloud, particularly its enhanced scalability, flexibility and potential for cost-savings, brought about a dramatic shift. Today, over 60% of business data is stored in the cloud and the global cloud computing market is worth almost a trillion dollars.2

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How does network security work?

As enterprises embrace new technologies like cloud computing, artificial intelligence (AI) and the Internet of Things (IoT), they increase the size of the attack surface hackers can exploit. Every year, complex cyberattacks involving malware (trojans), phishing, ransomware, social-engineering and distributed denial-of-service (DDoS) attacks cost companies millions.

Network security best practices and solutions are typically designed with three primary goals in mind:

  1. Prevent unauthorized access to network resources.
  2. Detect and stop cyberattacks in progress.
  3. Ensure that authorized users have secure access to the network resources they need.

Network security best practices

Practice network segmentation

Network segmentation, the practice of dividing a network into smaller segments, allows for organizations to implement more control over data and users on a network. Network segmentation reduces the size of the attack surface and the number of ways hackers can gain unauthorized access.

Enforce multifactor authentication (MFA)

Multifactor authentication (MFA) is a way of verifying a user’s identity through at least two distinct forms of proof, such as a password and facial ID. In network security, MFA provides an extra layer of protection in addition to a user’s password that can keep bad actors from gaining access to sensitive data.

Use virtual private networks (VPNs)

Virtual private networks (VPNs) are services that establish secure, encrypted connections for exchanging data and resources over the internet. Network security relies on VPNs to mask IP addresses, the location of a device in a network so that a user’s activity is harder to track.

VPNs have played a critical role in the evolution of remote work, enabling users to access company information and resources from anywhere in the world. This access includes working over public wifi networks in places like coffee shops or satellite offices.

Build a zero-trust framework

Zero trust, a modern security strategy designed for the cloud, focuses on securing individual user connections to a network rather than granting trust implicitly to all members.

Before the spread of cloud computing, network security focused on securing endpoints—devices that connected with networks and exchanged information—but this approach wasn’t as effective in a cloud environment.

Train and test employees regularly

The best network security solutions and systems are only effective if the teams charged with implementing them are regularly trained and undergo rigorous testing.

Organizations should ensure that users of a network are familiar with its security policies, also known as security protocols. They should also understand the steps to take when they suspect a data breach is occurring.

Types of network security solutions

In addition to best practices, organizations rely on a wide range of network security systems and tools designed to prevent cyberattacks from breaching networks. These solutions also help minimize the damage caused when breaches do occur.

Firewalls

A firewall is software or hardware that stops suspicious traffic from entering or leaving a network while letting legitimate traffic through. Firewalls can be deployed at the edges of a network or used internally to divide a larger network into smaller subnetworks. If one part of the network is compromised, hackers are still shut off from the rest.

Network access control (NAC) solutions

Network access control solutions authenticate and authorize users to determine who is allowed into a network and what they can do when they are inside. "Authentication" refers to confirming a user's identity and ensuring that they possess the appropriate permissions to access specific network resources.

NAC solutions are often used to enforce role-based access control (RBAC) policies, in which users' privileges are based on their job functions.

Cloud security

Cloud security solutions protect data centers, apps and other cloud assets from cyberattacks. Most cloud security solutions are simply standard network security measures (for example, firewalls, NACs and VPNs) applied to cloud environments. Many cloud service providers build security controls into their services or offer them as add-ons.

Intrusion detection and prevention systems (IDPSs)

An intrusion detection and prevention system (IDPS), sometimes called an intrusion prevention system, scans incoming traffic for security threats. These security tools evolved from intrusion detection systems (IDS), which only flagged suspicious activity for review.

IDPSs have the added ability to automatically respond to possible breaches by blocking traffic or resetting the connection.

Application security measures

Application security (AppSec) refers to systems and processes that security teams rely on to protect apps from cyberattacks. Because most modern enterprises use apps to carry out key business functions or process sensitive data, these apps frequently become prime targets for cyberattacks. And because so many business apps are hosted in public clouds, hackers can exploit their vulnerabilities to break into private company networks.

Some common examples of application security tools are web application firewalls, runtime application self-protection, static application security testing and dynamic application security testing.

Email security

Phishing, a type of cyberattack that uses fraudulent emails to trick people into sharing sensitive data, is one of the most common and effective cyberthreats. A wide range of email security tools and systems like spam filters and message encryption help organizations thwart common phishing attempts. Some more advanced email security tools even feature sandboxes, isolated environments where security professionals can inspect email attachments without exposing the entire network to their contents.

Related security technologies

While the following tools are not strictly network security tools, network administrators often use them to protect areas and assets on a network.

Data loss prevention (DLP)

Data loss prevention (DLP) refers to a set of information security strategies and tools that ensure sensitive data is not stolen nor accidentally leaked. DLP includes data security policies and purpose-built technologies that track data flows, encrypt sensitive information and raise alerts when suspicious activity is detected.

Endpoint security

Endpoint security solutions protect devices from hackers who can use them to sneak onto a network. Antivirus software can detect and destroy trojans, spyware and other malicious software on a device before it spreads to the rest of the network.

Web security

Web security encompasses a range of solutions and security policies that organizations depend on to protect networks, users and assets from various security risks. Web security solutions like secure web gateways, web application firewalls (WAFs) and antivirus software can block suspicious traffic and keep users from connecting to malicious apps.

User and entity behavior analytics (UEBA)

User and entity behavior analytics (UEBA) uses behavioral analytics and machine learning (ML) to flag suspicious activity. UEBA can help catch insider threats and hackers who have hijacked user accounts to gain unauthorized access to systems or data.

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Benefits of network security solutions

As the frequency and cost of cyberattacks rise, companies of all sizes across a wide range of industries are hungry for new network security solutions. Here are some of the most common benefits that they can provide.

  • Lower cyber risk: Enterprises that develop strong network and web security strategies can significantly reduce their exposure to financial loss, operational damage and reputational harm. These risks stem from threats to their digital assets—commonly referred to as cyber risks.
  • Greater data privacy: Reducing cyber risk and enhancing network security helps prevent leaking sensitive information through data breaches, particularly for enterprises that operate in highly regulated industries like healthcare, finance and government.
  • Better business continuity: Business continuity, an organization’s ability to maintain critical business functions, minimize downtime and resume operations after a disruption, depends on effective network security solutions and best practices.
  • Higher network performance: Protecting networks from cyberattacks isn’t the only benefit network security provides. Secure networks boost performance because they resist interruptions and shutdowns caused by attacks.
  • Stronger access control: More secure networks offer stronger access control over which resources are available to users and which are restricted. Various tools and methods allow organizations to effectively manage access to the kinds of information that, if leaked, could significantly impact their business.

Enterprise network security use cases

Enterprise network security solutions and best practices help organizations prevent cybercriminals from a wide range of cyberthreats. Here are five of the most common use cases.

Advanced Persistent Threat (APT) deterrence

Advanced Persistent Threats (APTs) are cyberattacks that can go undetected in a system or network for long periods of time while hackers steal sensitive data, conduct cyber espionage or sabotage computer systems.

APTs are highly damaging because they are designed to go undetected for so long, a characteristic that makes them difficult for even the most advanced network security solutions to detect and deter.

Enhanced security information and event management (SIEM)

Security information and event management (SIEM) is a kind of information security solution that helps organizations recognize and address potential security threats and vulnerabilities before they can disrupt business operations.

In terms of network security, SIEM systems help teams detect irregularities in user behavior and network traffic that could be evidence of a cyberattack.

Remote access for authorized users

In addition to preventing unauthorized access, network security solutions must ensure that authorized users can access the resources they need. Third-party contractors, for example, must be able to log in to networks—often remotely—without compromising network integrity.

To reduce the risk of bad actors gaining unauthorized remote access, network security systems rely on a combination of MFA, network segmentation and robust policy enforcement.

Preventing data breaches in gen AI applications

Generative AI (gen AI) is AI that can create original content like text, images and video in response to a user’s request. As more enterprises seek to leverage many applications, the risk of exposing sensitive data is increasing.

Network security solves like web browsers that automate policy enforcement to prohibit users from sharing personally identifiable information (PII) with gen AI apps can help.

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      Footnotes

      1. Network security market size, Fortune Business Insights, June 2025

      2. 55 cloud computing statistics for 2025, Spacelift, July 2025