Zero Trust Security: How to Configure Firewalls

Whether it is firewall configuration, Zero Trust policies, or security setup, these are important players in contemporary cybersecurity. To meet the changing needs of businesses today, we now require a security-first approach and the Zero Trust framework provides the most comprehensive approach to accomplish this. Setting up firewalls for Zero Trust limits access to your network to only authorized users and devices.

Here is a step-by-step guide for firewall changes for Zero Trust security.

1. Setting Up Access Rules

Firewalls serve as gatekeepers, determining who can enter and what resources they have access to. Zero Trust means strict access rules:

• Default to denies all – Permit only explicitly defined traffic.
• Allow by Least Privilege – Users should have access to the least that is required.
• Create rules for users/devices – Whitelist covered IPs and blacklist everything else.
• Deploy Application Layer Filtering – Block inappropriate applications or limit access by roles.
• Time-based access – Restrict access to certain very critical systems based not only on user roles but also based on time.

If you are renting a firewall, make sure that you have customizable policies at hand. You just need your access rules to be dynamic, without deep expertise needed.

2. Network Segmentation

Why would you let all of your network be accessible at once? That’s risky. Instead, isolate the network for better security.

• Build virtual LANs (VLANs) – Segment traffic by departments.
• Isolate critical assets – Keep sensitive data separate from general access.
• Do micro-segmentation – Segment networks into microscopic isolated areas.
• Containing east-west traffic – Internal traffic should be controlled and monitored.
• Software-defined perimeters – Grant access dynamically based on need.

Renting firewalls? Confirm support for advanced segmentation. Certain models implement built-in Zero Trust segmentation, helping you out even further.

3. Implementing Identity and Access Control

Passwords aren’t sufficient on their own. Zero Trust advocates for identity-based access so that only authorized users and devices are able to connect.

• Implement Multi-Factor Authentication (MFA) – Add more login steps to secure access.
• Connect with Identity Providers (IdP) – Authenticate users before providing them access.
• Implement Role-Based Access Control (RBAC) – Permissions should be assigned at the role level, not the individual user level.
• Limit device access – Only authorized devices are able to connect with the firewall.
• Ongoing Identity Checks – Always know who is trying to get to what.

While renting a firewall, check if it supports identity-based access and that it can integrate with Active Directory, Okta, or any other IdP for smooth authentication.

4. Monitoring & Alerts

Just putting in a few firewall rules isn’t enough. You need constant monitoring to help protect from security threats that might pass through your defenses.

• Turn on real-time logging – Log every security incident in its entirety.
• Implement IDS/IPS – Prevent suspicious activity in real time.
• Use AI threat detection – Some advanced firewalls even feature AI-based alerts.
• Set up automation responses – Kill the bad connections right away.
• Alerts reviewed daily – No threat goes unseen.

If you rent a firewall, choose one that is bundled with monitoring tools and real-time dashboards that offer instant visibility.

5. Updating Policies

Threats come in waves—outdated firewall rules aren’t going to help you. Ensure policies are kept current with evolving threats.

• Revisit business rules weekly – Update access according to business requirements.
• Regular firmware patching – Old firewalls have vulnerabilities that can be exploited.
• Review whitelists to remove access for former employees and unused systems.
• Regularly test firewall configurations – Conduct penetration tests to identify vulnerabilities.

If you’re renting firewalls, choose one that not only manages stress for you but also has policy updates built into their service—keeping you secure without increasing your workload.

Final Thoughts

Zero Trust is not just a theory — it’s a security imperative. In a Zero Trust implementation, the initial line of defense is a well-ordered firewall. This brings us to consider each factor when it comes to security guidelines (access rules, network segmentation, identity-based access, monitoring, policy updates, etc.), regardless of whether they are provided in-house or rented from the cloud.

Firewall configuration, Zero Trust policies, security setup — do those things correctly, and you will build a solid cyber-security foundation for your business.