Network security covers all the measures and practices that protect the flow of data between devices, systems, and users within your network. For SMBs, this isn't an academic exercise – 88% of data breaches at small businesses stem from preventable security gaps. And since NIS2 came into force in December 2025, many of these measures have legal weight for companies operating in Germany.

Whether it's data protection, smooth operations, or secure collaboration – these five measures are essential.

1. Secure your network with a firewall

A firewall acts as a digital gatekeeper, blocking unauthorised access and malicious activity. As a barrier between your internal network and external threats, it monitors incoming and outgoing traffic – keeping out unauthorised users and potentially harmful data.

What to do: Make sure your firewall is actively configured, not just running on factory defaults. Many routers come with a built-in firewall that rarely gets touched. Regularly reviewing what traffic is allowed in and out is basic IT hygiene.

For SMBs, a next-generation firewall (NGFW) adds significant value – it doesn't just filter ports, it also analyses applications and user behaviour. This is especially relevant when your team uses cloud-based tools like Google Workspace or Microsoft 365.

2. Protect data with a VPN

With remote work, employees often access company resources from multiple locations. Virtual Private Networks (VPNs) encrypt connections and secure data transfers – even over public networks. They create protected tunnels between remote devices and your company network, making data interception practically impossible.

What to do: Set up a business VPN and make sure employees use it whenever they work outside the office. Educate your team on why public Wi-Fi – in cafés, hotels, co-working spaces – is a real security risk without a VPN.

Important: a VPN protects the connection but doesn't replace strong passwords or MFA. It's one layer of protection among several.

3. Stay in control with centralised network monitoring

Real-time monitoring is essential for detecting threats and vulnerabilities quickly. With central management, IT administrators get real-time visibility into network traffic, can identify anomalies, and respond to incidents immediately. This proactive approach prevents breaches rather than reacting after the fact.

What to do: Use a monitoring tool that triggers alerts for unusual behaviour: suspicious login attempts, unusually high data transfers, or new devices appearing on the network. For SMBs without an in-house IT team, a managed IT service can handle this monitoring around the clock.

4. Implement effective network segmentation

By dividing your network into isolated segments, you protect sensitive data from unauthorised access. A classic example: a guest Wi-Fi with restricted access prevents visitors or external contractors from reaching your internal systems.

What to do: At minimum, separate three areas: the internal employee network, a guest Wi-Fi, and – if applicable – a production network for IoT devices or servers. This way, a compromised device stays isolated within one segment rather than spreading through the entire network.

Segmentation is also NIS2-relevant: the principle of minimal exposure – no system has more network access than necessary – is a core requirement under NIS2 Article 21.

5. Optimise access management with centralised authentication

Centralised authentication simplifies access control by linking cloud networks or VPNs with an identity provider like Microsoft 365 or Google Workspace. Only authorised users get access, configuration becomes more efficient, and employees simply log in with their existing company accounts.

What to do: Enable multi-factor authentication (MFA) for all company accounts – not just admin access. MFA blocks over 99% of credential-based attacks and has been mandatory for NIS2-compliant companies in Germany since December 2025. Importantly: don't make MFA optional – enforce it at the system level so employees can't bypass it.

Conclusion

In a world where data constantly flows between devices, systems, and users, network security isn't a one-time project – it's an ongoing process. With these five measures – firewall, VPN, real-time monitoring, network segmentation, and centralised authentication – you protect your business against the most common cyber risks.

If this feels technically complex, don't worry: deeploi's IT experts are here to help with implementation – from setup through to ongoing monitoring, even if you don't have an in-house IT team.

FAQ

What is network security and why does it matter for SMBs?

‍Network security covers all measures that protect the flow of data between devices, systems, and users in your company. For SMBs it's especially important because smaller businesses are often seen as easy targets – 88% of data breaches at small companies stem from preventable gaps. At the same time, NIS2 and GDPR make certain measures legally mandatory for in-scope companies.

Do I need a firewall if I mainly use cloud tools?

‍Yes – even in cloud-first setups, a firewall makes sense. It protects traffic leaving your local network and prevents attackers from entering through compromised devices. For purely cloud environments, identity providers and MFA complement the traditional firewall.

How do I set up a secure guest Wi-Fi?

‍Most modern routers and access points have a built-in VLAN or guest Wi-Fi function. Enable it in your router settings, set a separate password, and make sure the guest network has no access to internal resources like printers, servers, or shared drives. It typically takes less than 15 minutes.

What's the difference between MFA and a strong password?

‍A strong password is one security layer. MFA adds a second – for example, a code on your phone. Even if a password is stolen, an attacker can't gain access without the second factor. MFA reduces the risk of a successful attack by over 99%.

Can deeploi handle network security for my company?

‍deeploi covers the technical layer of network security as a managed service: endpoint protection through the WithSecure integration, automatic patches, centralised device management, and access controls. For more complex network infrastructure, deeploi's IT experts work directly with you.

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