How to conduct a network audit in a corporate environment

What a network audit should achieve

The goal is not to produce a lengthy technical report that goes unread. The objective is to reduce operational risk and create a plan for predictable operations. The audit must answer several practical questions: which systems depend on the network, who has access to them, what would happen in the event of a failure, and whether a realistic recovery method exists.

The scope depends on the company's size and profile. In a small office, it might cover internet connectivity, the firewall, the Wi-Fi network, workstations, printers, and cloud services. For an organization with multiple locations, a warehouse, a production environment, or on-site servers, the audit also examines VPN connections, backup lines, network segmentation, communication equipment, and inter-site links.

It is important to view the audit as a snapshot followed by concrete actions. Simply identifying a problem without assigning an owner, a deadline, and a priority level does not improve security.

How to conduct a network audit step-by-step

1. Define the scope and business-critical services

Before scanning the network, it must be clear what is being checked and why. A productive initial meeting involves the manager, the internal IT lead, and representatives from key departments where necessary. This helps identify which applications and processes cannot afford downtime—such as accounting software, ERP systems, file servers, VoIP telephony, warehouse management systems, and access to cloud platforms or remote work tools.

This step establishes the correct priorities. For example, an old switch in a conference room does not pose the same risk as a device through which access to all corporate data flows. The technical issue must be translated into business terms: potential downtime, loss of productivity, risk to personal data, delayed customer service, or the inability to work remotely.

2. Conducting a full inventory

The next step is to identify the actual assets on the network. This includes firewalls, routers, switches, wireless controllers and access points, servers, NAS devices, computers, printers, IP cameras, phones, and specialized equipment. Virtual machines, cloud resources, and network services that are not physically located in the office but are part of daily operations are also checked.

The inventory often reveals discrepancies between documentation and the actual environment. Issues such as unsupported legacy devices, network ports with unclear connections, personal devices with internal network access, and active user accounts belonging to former employees are frequently encountered. Each such element increases the attack surface and complicates incident response.

A useful inventory record contains more than just the model and serial number. It indicates the device's location, role, maintenance provider, software used, warranty status, and scheduled replacement date. This transforms the inventory into a budgeting tool rather than merely a technical list.

3. Mapping topology and dependencies

The network diagram illustrates how devices and services are interconnected. It must include Internet Service Providers (ISPs), the firewall, core switches, wireless networks, servers, VLAN segments, VPN tunnels, and connections to other offices or cloud environments.

The focus here is on identifying single points of failure. If a switch, power supply, or internet line fails, will the entire organization come to a halt? Is there redundant connectivity? Are critical servers and network equipment protected by a UPS that is properly sized and tested? A backup device is only valuable if it is configured, monitored, and capable of taking over operations in a real-world scenario.

Segmentation is particularly important. Workstations, servers, guest Wi-Fi users, IP cameras, and IoT devices should not automatically share the same level of access. Separating them into distinct segments limits the potential impact if a compromised device is used to move laterally toward more valuable systems.

4. Security configurations and controls are verified

This is the core of the audit. Checks are performed on firmware and operating system versions, firewall policies, open services, remote access, VPN settings, Wi-Fi encryption, and administrator account privileges. Multi-factor authentication mechanisms are also evaluated, particularly for cloud platforms, administrative panels, and remote access.

Particular attention is paid to default or shared passwords, accounts without a clearly defined owner, and access via outdated protocols. Not every legacy system can be replaced immediately. When this is not feasible, risk is mitigated through network isolation, restricted access rules, enhanced monitoring, and a concrete replacement plan.

The audit should also examine the logs. If unauthorized access is suspected, the organization must be able to determine who accessed key systems, as well as when and from where. Logs that are not retained long enough or are never reviewed do not provide effective control.

5. Performance and reliability are evaluated

A secure network is not necessarily an efficient one. Therefore, the analysis covers internet connection load, switch capacity, Wi-Fi coverage, packet loss, latency, and frequent interruptions. In the case of telephony or video calls, even brief disruptions can significantly impact customer service.

The assessment must take the company's specific operations into account. An office with ten users relying primarily on cloud applications has different needs than an organization utilizing warehouse terminals, cameras, local servers, and numerous remote employees. A faster internet connection is not always the solution; sometimes the issue stems from poorly positioned Wi-Fi access points, a lack of traffic prioritization, or outdated equipment creating a bottleneck.

6. Backup and recovery processes are checked

A network audit is directly linked to business continuity. Checks are performed to determine where backups are stored, whether they are isolated from the primary environment, and if recovery procedures have been tested. A backup plan that exists only on paper offers no protection against ransomware, hardware failure, or human error.

Best practice dictates having clearly defined recovery objectives: the maximum amount of data loss that can be tolerated and the timeframe within which a critical service must be restored. These parameters help determine the right combination of local, cloud-based, and isolated backups. ## The report must lead to a solution

The ultimate value of an audit lies in the report and the action plan. Findings should be prioritized based on risk, probability, and business impact. Instead of a generic statement like "security needs improvement," a useful report specifies exactly which devices require critical updates, which accounts need to be removed, where network segmentation is lacking, and what actions are required.

A practical approach is to categorize measures into immediate, short-term, and strategic actions. Immediate actions might include changing compromised passwords, removing unnecessary external access, or updating firewall configurations. Short-term measures cover organizing network documentation, setting up monitoring systems, and testing backups. Strategic solutions could involve replacing hardware, establishing redundant connectivity, or implementing improved network segmentation.

For companies subject to GDPR, ISO 27001, or NIS2 requirements, the audit also provides a verifiable basis for risk management. While it does not replace a comprehensive compliance assessment, it demonstrates whether technical controls effectively support the organization's commitments.

How often is a network audit needed?

For most small and medium-sized organizations, a full network audit once a year is a reasonable minimum. Additional checks are necessary following significant changes, such as moving to a new office, opening a new location, implementing an ERP system, migrating to the cloud, switching internet service providers, or experiencing a security incident. Between annual audits, proactive monitoring and regular reviews of updates, backups, and user access keep the environment under control. Thus, the audit becomes not just a one-off effort, but a foundation for the disciplined management of IT infrastructure.

The best time for a network audit is not after a major failure. It is when the business is operating normally and there is time to address risks in a planned manner, with clear accountability and without costly disruptions.