Traditionally, every enterprise is reliant on a network to work. The network is one of the most critical pieces of infrastructure any organization owns and it sends traffic all the time: email, applications, file sharing, customer transactions and internal communications all flow across that network which makes it both very useful but also incredibly interesting to an attacker. For any organization piecing together a cohesive defense, network security boils down to an understanding that goes beyond the name: what it means from an enterprise IT perspective and how it relates to or differs from adjacent disciplines like endpoint security or application security.
Defining Network Security
In its most basic sense, network security is the collection of technologies, equipment, and policies an organization applies to help ensure the safety of its networks and the data that travels across them. It determines how traffic enters and leaves the network, where parts of the network can communicate with each other within the architecture, and what information is required to detect external hacking attempts.
This is different (but still related) to endpoint security, whereby you are securing a specific device: laptop, server or mobile phone; Rather than focusing specifically on the devices themselves, network security focuses on the connective tissue between those devices who you trust to talk to whom (the traffic flows), where you draw the line that separates trusted from untrusted zones and what is allowed through, also known as policy.
Everybody who is researching what is network security for enterprises will soon find that the discipline isn 1 tool or technology but layered practices working in combination with each other. No single control will ever be enough by itself; effective network security depends on many overlapping defenses, a.k.a. defense-in-depth.
Network Security Through Three Phases
One way to understand the field of network security is by splitting it into three parts in chronological order: Protection, Detection and Reaction. There are three phases, each looking at a different portion of an organization’s defensive posture and a mature security program invests accordingly across all three.
Protection
The best way to get protection is to set our system and network as correctly and securely as possible from the beginning. This involves changing device configurations, employing the least privileged access model for authorized controls, dividing the network in logical zones and patching vulnerabilities as soon as they become available. Protection provides a baseline against which the adversary’s attack surface is reduced.
Detection
Is the monitoring that must occur to detect when something has changed unintentionally: configuration drift, an exceptionally low number of requests, etc. Detection capabilities rely on a clear model of normal enterprise network behavior, with anomalies contrasting against that baseline.
Reaction
Reaction is the organization’s ability to respond quickly and effectively once a problem has been identified, containing the issue and returning systems to a secure state. Detailed coverage of network security definition and methods makes clear that no single line of defense is sufficient on its own. An adversary who breaches one layer should still find additional layers standing between them and the organization’s most sensitive assets, which is the practical meaning of defense in depth.
Essential Building Blocks of Enterprise-Level Network Security
The Practical Toolkit. This is the set of techniques and technologies through which enterprises implement network security.
- Access control determines who, and indeed what can connect to the network and what resources they may have access to once connected. With role-based access control models, users and systems are granted only the access permissions necessary to perform their function thus minimizing the impact of any single device or account compromised.
- Firewalls continue to be a fundamental control, defining the boundary of an internal trusted network and untrusted external networks and routing traffic through that border. Firewalls by themselves do not make a complete security posture, yet no enterprise network security strategy is complete without one.
- Intrusion detection and prevention systems (IDPS) monitor network traffic; when the traffic data suggests anomalous behavior relative to a baseline established from historical data, the IDPS matches it against known attack patterns and automatically blocks such activity where possible.
- Network segmentation separates the network into different zones so that a compromise of one zone doesn’t secure an attacker the rest of the environment as well. This containment mechanism is especially critical for safeguarding the most sensitive systems and data across an organization.
- Encryption secures data traversing the network, as if traffic is intercepted, it will be indistinguishable from noise to anyone lacking the appropriate decryption key. VPNs take this protection a step further for remote connections, providing a secure tunnel from the device to its destination on the corporate network over an open internet connection.
Frequent Gaps That Can Sabotage Network Security
Large security investments can still leave organizations very vulnerable due to a relatively small number of repeatable, avoidable gaps. Weak password practices remain a leading attack vector, especially when users use the same weak credentials across multiple systems. Another longstanding vulnerability that allows attackers to exploit known weaknesses long after a fix has become available is badly out-of-date software.
Another gap, this one less technical but no less consequential, is insufficient training. Even a perfectly configured corporate network is vulnerable when an employee clicks on the wrong link or falls victim to a social engineering attack which is why continuous security awareness training is considered core network security rather than an optional extra.
Excessive access privileges compound the risk of any of these other gaps. When users or systems hold more access than their role requires, a single compromised account or credential can give an attacker a much wider foothold than would otherwise be possible. Reviewing common network security mistakes reinforces how often breaches trace back not to sophisticated attack techniques but to these basic, addressable weaknesses in everyday network hygiene.
Network Security in a Cloud-Connected Enterprise
The majority of contemporary enterprise networks are not a self-contained environment all on their own. Almost all organizations work in a hybrid infrastructure today, with on-premises components integrating with cloud-hosted services and it is essential that network security goes the distance across that entire footprint every day.
This introduces a coordination challenge. The cloud may have its own security controls and policies that the cloud provider applies to their platform, but those controls often do not map cleanly back to an organization’s internal network security policies. Getting this gap from A to B takes a bit of work: extending visibility, access controls and monitoring so that security policy is enforced across on-prem and cloud footprint such that it applies with no regard to where a workload exists or user sits.
Since remote work has become standard practice for so many organizations, the network perimeter is essentially eradicated. Employees connect with home networks, public Wi-Fi, and a huge variety of personal and managed devices that must be considered in a complete network security solution. This has propelled an increased focus on zero-trust via identity-based security models, verifying both the user and device continuously, versus assuming anything within a traditional network boundary to be trusted.
Building a Network Security Program
Defining proper network security is not a one-time effort with an endpoint; it is an ongoing operation. Organizations usually start with basic controls, firewalls, authentication, encryption, and endpoint protection– before adding on more advanced features like behavioral analytics, automated threat detection, and centralized security monitoring for a whole network environment.
Maintaining the posture requires regular security audits, patch management and employee training. While the network undergoes constant change with new cloud services, new remote work patterns, and new applications being added, so too must the security program. The best enterprises know that network security is a process, not a project; constantly improving to remain defensively postured in the long haul.
Frequently Asked Questions
What is the difference between network security and cybersecurity?
Cybersecurity is the broader practice of securing all IT assets against attacks, from networks and applications to endpoints and data. Network security is a subfield focused solely on network infrastructure and the traffic that flows across it. Application and endpoint security are two interrelated, complementary areas that together play a significant role in cybersecurity as a whole.
What is defense in depth, and why it is the heart of all network security?
Defense in depth is the approach that an organization follows multiple overlapping layers of security controls instead of one single line of defense. Any individual security tool can be circumvented by a skilled attacker and therefore layered protection, detection, and response capabilities can greatly decrease the chances of a complete network exploitation due to failure of one layer.
How will remote work make enterprise network security more challenging?
Since employees work from home, public Wi-Fi and personal devices none of which have the same security controls as a managed office environment remote work multiplies the attack surface. This forces organizations to apply security policies beyond the traditional network perimeter which results in mandatory VPN use, two-factor authentication and continuous verification of users or devices regardless of location.