Businesses depend on their networks for nearly everything from accessing files and applications to communicating with customers, processing transactions, and connecting employees working remotely.
That also makes the network an important target for cyber threats.
Protecting a business network isn’t as simple as installing a firewall or antivirus software. Modern network security uses multiple technologies, policies, and security controls that work together to protect users, devices, systems, and data.
So, what are the different types of network security, and what does each one actually do?
What is Network Security
Network security refers to the technologies, processes, and controls used to protect a company’s network, connected devices, applications, and data from unauthorized access, misuse, disruption, and cyber threats.
Years ago, network security was often heavily focused on creating a secure perimeter around an office network.
Today’s business environments are much more complicated.
Employees may work remotely. Applications may run in the cloud. Employees access company information from laptops and mobile devices. Businesses may operate multiple locations, and third-party vendors may need access to certain systems.
As business networks have changed, network security has had to change with them.
Rather than relying on one defensive barrier, businesses can use multiple layers of network security to help prevent, identify, contain, and respond to threats.
What Are the Different Types of Network Security?
There are are many types of network security, and each protects a different part of a business’s technology environment. Some controls focus on preventing unauthorized access, while others help detect suspicious activity, protect connected devices, secure data, or limit how far a threat can spread.
A firewall is one of the most recognizable types of network security.
Firewalls monitor and control network traffic based on established security rules. They essentially act as a checkpoint between different networks or network segments, deciding which traffic should be allowed through and which should be blocked.
For example, a firewall can be configured to restrict traffic coming from certain network addresses, applications, or ports while allowing legitimate business traffic.
Modern firewalls may also provide capabilities beyond basic traffic filtering, including application awareness, intrusion prevention, threat detection, and other security functions.
However, having a firewall doesn’t mean a business network is completely protected. A firewall is one layer of security, not the entire security strategy.
2. Network Monitoring
You can’t protect a network effectively if you don’t know what’s happening on it.
Network monitoring provides visibility into the health, availability, performance, and activity of network infrastructure.
Depending on the tools being used, monitoring may help identify:
- Unusual network traffic
- Devices going offline
- Performance problems
- Connectivity issues
- Network equipment failures
- Unexpected activity
- Resource utilization
- Potential security events
Monitoring can also help IT teams identify problems before employees begin reporting that something isn’t working.
From a security perspective, unusual network activity can sometimes be an early indicator that an account, device, or system requires investigation.
3. Intrusion Detection and Prevention
Intrusion detection and prevention technologies are designed to identify suspicious or potentially malicious activity.
An Intrusion Detection System (IDS) focuses on detecting activity and generating alerts.
An Intrusion Prevention System (IPS) can go a step further by taking action to block certain detected threats.
These technologies can inspect network traffic for known attack patterns, suspicious behavior, or activity that violates established security policies.
Think of it this way: A firewall controls which traffic is allowed through the door.
Intrusion detection and prevention technologies help identify whether something suspicious is happening with the traffic that’s being allowed through.
4. Network Segmentation
Imagine that every room in an office building could be accessed with the same key.
If someone obtained that key, they could potentially move throughout the entire building.
A poorly segmented network can create a similar problem.
Network segmentation divides a larger network into smaller sections or subnetworks. Access and communication between those areas can then be controlled.
For example, a business might separate:
- Employee devices
- Guest Wi-Fi
- Servers
- Security cameras
- Internet of Things devices
- Sensitive financial systems
- Operational technology
If one part of the network becomes compromised, segmentation can help limit an attacker’s ability to move freely into other areas.
CISA describes segmentation as a way to create boundaries that limit access to devices, data, and applications while restricting communications between networks. Segmentation can also make malicious traffic easier to detect, prevent, and contain.
5. Secure Remote Access and VPNs
Remote and hybrid work changed where employees access company resources.
Employees may connect from home offices, customer locations, hotels, or while traveling.
Secure remote access technologies help protect those connections and control who can remotely access company systems.
A Virtual Private Network, or VPN, is one method businesses have traditionally used to create an encrypted connection between a remote user and company resources.
However, remote access security should involve more than simply providing employees with a VPN.
Businesses should also consider:
- User authentication
- Multi-factor authentication
- Device security
- Access permissions
- Session monitoring
- Which resources remote users actually need
Remote access should give employees what they need to work without unnecessarily exposing the rest of the network.
6. Multi-Factor Authentication
Passwords can be stolen. Employees may reuse them, enter them into phishing websites, or unknowingly expose them through compromised accounts. Multi-factor authentication (MFA) adds another verification requirement before access is granted. Instead of relying entirely on something the user knows, their password, MFA requires another authentication factor.
That means a stolen password alone may not be enough for an attacker to access a protected account.
MFA is particularly important for:
- Remote access
- Cloud applications
- Administrative accounts
- VPN access
- Microsoft 365
- Sensitive business systems
MFA doesn’t replace good password practices or other network security controls, but it creates another obstacle for attackers attempting to use compromised credentials.
7. Network Access Control
Not every device should automatically be allowed to connect to your business network.
Network Access Control (NAC) helps organizations control which users and devices can access network resources.
For example, a business may want to determine:
- Who is connecting?
- What device are they using?
- Is that device authorized?
- Does the device meet security requirements?
- What parts of the network should that user or device be allowed to access?
A company-owned laptop used by an employee may require different access than a visitor’s personal phone.
Network access controls help businesses make those distinctions.
8. Endpoint Security
Every laptop, desktop, and other endpoint connected to the network can potentially become an entry point for an attacker. Endpoint security protects these devices from threats such as malware, ransomware, malicious files, and suspicious activity.
Modern endpoint protection can include technologies such as antivirus, endpoint detection and response, behavioral monitoring, application controls, and automated threat response.
Endpoint security and network security work closely together.
If an employee accidentally opens a malicious attachment, endpoint protection may help detect or stop the threat before it can spread further through the business environment.
9. DNS Security
Every time an employee visits a website, the Domain Name System (DNS) helps translate the website name into the information computers use to locate it. Attackers can take advantage of web traffic by directing users toward malicious websites or infrastructure.
DNS security can help prevent devices from connecting to known malicious or suspicious domains. For example, an employee may click a phishing link that attempts to send them to a malicious website.
Email security may catch the message first. But if it doesn’t, DNS filtering may provide another opportunity to prevent the connection.
This is a good example of why network security works best in layers.
10. Email Security
Email may not immediately seem like network security, but it is one of the most common ways attackers attempt to gain access to business environments.
Phishing emails can be used to:
- Steal passwords
- Deliver malware
- Spread ransomware
- Impersonate executives
- Redirect payments
- Gain access to Microsoft 365 accounts
Email security solutions can help identify malicious links, suspicious attachments, impersonation attempts, spam, and other threats before they reach employees. But technical controls can’t catch every malicious message.
That’s why email security works best alongside MFA, endpoint protection, DNS filtering, employee training, and other security layers.
11. Encryption
Encryption helps protect information by making it unreadable without the appropriate authorization or cryptographic key.
For network security, encryption is particularly important when information is being transmitted between systems.
Think about the sensitive information businesses send every day:
- Customer information.
- Login credentials.
- Financial records.
- Employee information.
- Business documents.
Encrypting data in transit helps protect that information from being read if communications are intercepted. Encryption can also be used to protect data stored on devices and systems, providing another layer of protection for sensitive business information.
12. Patch and Vulnerability Management
Sometimes attackers don’t need to invent a new way into a network. They can exploit a security vulnerability that’s already known. Software vendors regularly release security updates and patches to address vulnerabilities in operating systems, applications, network equipment, and other technologies.
Patch management helps ensure those updates are identified, evaluated, and installed appropriately. Businesses also need to understand what vulnerabilities exist within their environments.
Vulnerability management can include:
- Identifying vulnerabilities
- Evaluating their severity
- Prioritizing remediation
- Installing patches
- Updating software
- Replacing unsupported systems
- Verifying that vulnerabilities have been addressed
Ignoring updates for months or years can leave known weaknesses available for attackers to exploit.
13. Wireless Network Security
Business Wi-Fi needs protection too. An improperly configured wireless network could provide unauthorized users with an avenue into company resources.
Wireless network security can include:
- Strong encryption
- Secure authentication
- Properly configured access points
- Separate guest networks
- Strong administrative credentials
- Firmware updates
- Network segmentation
- Monitoring
One particularly important practice is separating guest Wi-Fi from the internal business network. Customers and visitors may need internet access. They probably don’t need access to your servers, printers, business systems, and employee devices.
14. Zero Trust Security
Traditional network security often operated around the idea of a trusted internal network and an untrusted outside world.
Modern environments make that distinction much harder.
- Employees work remotely.
- Applications live in the cloud.
- Business data exists outside the office.
- Users connect from different devices and locations.
Zero Trust approaches security differently. Instead of automatically trusting a user or device simply because it’s connected to the company network, access decisions are based on factors such as identity, device, authorization, and the resource being requested.
NIST describes Zero Trust as moving security away from reliance on a static network perimeter and toward protecting users, assets, and resources. It specifically states that trust shouldn’t be granted solely because of a user’s physical or network location.
In simple terms:
Being “inside” the network doesn’t automatically mean you should be trusted.
Zero Trust can involve technologies and practices such as:
- Strong authentication
- Least-privilege access
- Device verification
- Network segmentation
- Identity management
- Continuous monitoring
- Access policies
It is a security strategy rather than one single product businesses can simply install.
15. Security Awareness Training
Your employees interact with your network and business systems every day. That makes the human side of security important too.
Security awareness training teaches employees how to recognize and respond to threats such as:
- Phishing emails
- Fake login pages
- Suspicious attachments
- Social engineering
- Unexpected MFA requests
- Password attacks
- Business email compromise
- Unsafe file sharing
Imagine that your company has an advanced firewall, endpoint protection, network monitoring, and strong access controls.
Then an employee receives a fake Microsoft 365 login page and willingly enters their credentials. Technology can reduce risk, but employees still need to understand the threats they’re likely to encounter.
This is the most important part. Businesses shouldn’t look at these security controls as completely separate solutions. They are most effective when they overlap.
Consider a phishing attack. An attacker sends an employee a malicious email.
Layer 1: Email Security
The email security system attempts to identify and block the message.
But suppose the message gets through.
Layer 2: Security Awareness
The employee may recognize the warning signs and report the message instead of interacting with it. But suppose they click the link.
Layer 3: DNS/Web Security
The connection to the malicious website may be blocked. Suppose that doesn’t happen either, and the employee enters their password.
Layer 4: MFA
The attacker may still need another authentication factor before accessing the employee’s account. Suppose the attacker manages to compromise a device or account.
Layer 5: Access Controls & Segmentation
The compromised identity or device shouldn’t automatically have access to every resource in the company.
Layer 6: Monitoring & Detection
Unusual network or account activity may trigger an alert for investigation.
Layer 7: Backup & Disaster Recovery
If an attack ultimately damages or encrypts company data, properly protected backups can provide another recovery option.
One security control can fail. Multiple overlapping controls make it harder for one mistake or vulnerability to turn into a company-wide incident.
Why a Firewall Alone Isn't Enough
It’s easy to think of cybersecurity as building a wall around the network. Install a good firewall and keep the bad guys outside. Modern business networks don’t work that way anymore.
NIST’s guidance for modern enterprise networks recognizes technologies ranging from firewalls and VPNs to microsegmentation, secure web gateways, Zero Trust Network Access, cloud security controls, and other approaches.
A firewall can’t prevent every employee from giving away their Microsoft 365 password. Endpoint protection can’t control every inappropriate permission. MFA can’t patch an outdated server. Security awareness training can’t replace technical controls. Network segmentation can’t stop every phishing email. Each control solves a different part of the problem. That’s why layered security is so important.
Does Every Business Need All 15 Types of Network Security?
Not necessarily.
A 15-person accounting firm doesn’t have the same infrastructure as a manufacturer operating several facilities. A healthcare organization may have different compliance and data-protection requirements than a small retail business.
The right network security strategy depends on factors such as:
- Business size
- Number of locations
- Number of employees
- Remote and hybrid work
- Types of data stored
- Cloud applications
- Servers and network infrastructure
- Regulatory requirements
- Third-party access
- Business applications
- Cybersecurity risks
The goal shouldn’t be to buy every security product available. It should be to understand what you’re protecting, what could go wrong, and which controls reduce those risks.
Signs Your Business May Need to Improve Network Security
Network security problems aren’t always obvious. A business doesn’t need to wait for a ransomware attack to evaluate its environment.
Potential warning signs include:
- Outdated firewalls or network equipment
- Unsupported operating systems
- Employees sharing accounts
- No MFA
- Flat networks with little segmentation
- Guest devices connecting to the internal network
- No centralized network monitoring
- Inconsistent patching
- Former employees retaining access
- Unmanaged remote access
- Unknown devices connected to the network
- No documented cybersecurity policies
- No tested backup and recovery strategy
- Recurring malware or account compromises
If you aren’t sure which protections are currently in place, that itself may be a reason to assess the environment.
