Troubleshooting Common Issues with Managed Firewall Services

Cyberattacks are on the rise, with businesses experiencing a 38% increase in global cyber threats in 2024 alone. A well-managed firewall is your first line of defense against unauthorized access, malware, and data breaches. But what happens when your firewall itself starts causing issues?

From connectivity problems to misconfigurations, firewall-related issues can disrupt operations, slow down your network, or even leave your business exposed. Whether you’re using a cloud-based firewall, dedicated server protection, or firewall solutions from a hosting provider, troubleshooting these problems quickly is crucial.

This guide walks you through the most common managed firewall issues and how to fix them, ensuring your network remains secure and operational.

Common Managed Firewall Issues & How to Fix Them

1. Network Connectivity Problems

Symptoms:

Websites or applications failing to load

Frequent disconnects from internal servers or cloud services

Slow or unstable network performance

Possible Causes & Solutions:
✔ Overly Restrictive Firewall Rules – Check the firewall settings to ensure that legitimate traffic isn't being blocked. Review port configurations, allowlists, and access control lists (ACLs).
✔ DNS Resolution Issues – If your firewall isn't correctly resolving domain names, check your DNS settings and ensure firewall rules aren't blocking name resolution requests.
✔ Server Overload – If you're using a shared hosting environment, your firewall might be overwhelmed. Consider dedicated firewall resources or cloud-based firewall solutions for better scalability.

2. Unauthorized Access & False Positives

Symptoms:

Users unable to access applications despite having the correct permissions

Legitimate traffic being flagged as a security threat

Frequent login failures or blocked remote access

Possible Causes & Solutions:
✔ Misconfigured Access Control Policies – Review your user roles, IP whitelisting, and access restrictions to ensure they align with your security needs.
✔ Intrusion Prevention System (IPS) Sensitivity – If your managed firewall service includes an IPS, adjust its sensitivity settings to reduce false positives.
✔ Check Firewall Logs – Reviewing logs can help identify patterns of legitimate traffic being blocked, allowing you to tweak security policies accordingly.

3. Performance & Latency Issues

Symptoms:

Slow website loading times

High latency when accessing cloud services

Increased server response time

Possible Causes & Solutions:
✔ Firewall Bottlenecks – If the firewall is inspecting too much traffic, it could slow down your network. Enable selective deep packet inspection (DPI) instead of scanning all data packets.
✔ Bandwidth Overuse – High traffic volumes can overload your server and firewall. Consider load balancing or upgrading your hosting plan to ensure smooth performance.
✔ CDN & Firewall Conflicts – If you use a content delivery network (CDN), ensure it’s correctly configured to work with your firewall to avoid unnecessary traffic filtering.

4. Firewall Failing After an Update

Symptoms:

Firewall rules reset or become ineffective

Unexpected downtime after an update

Inability to access firewall management console

Possible Causes & Solutions:
✔ Firmware or Software Bugs – Some updates may introduce compatibility issues. If your firewall stopped working after an update, roll back to a stable version or apply vendor-recommended patches.
✔ Config File Corruption – If settings were erased or changed unexpectedly, restore your last working firewall configuration from a backup.
✔ Hosting Provider’s Restrictions – If using managed hosting, check if the provider applied security restrictions that conflict with your firewall settings.

5. VPN & Remote Access Issues

Symptoms:

Users unable to connect to a corporate VPN

Secure shell (SSH) or remote desktop protocol (RDP) connections failing

Slow VPN speeds despite adequate bandwidth

Possible Causes & Solutions:
✔ Firewall Blocking VPN Ports – Ensure that ports used for VPN connections (such as UDP 1194 for OpenVPN or TCP 443 for SSL VPNs) are open.
✔ Incorrect NAT or Port Forwarding – If VPN traffic is being misrouted, review your network address translation (NAT) settings to ensure proper forwarding.
✔ Cloud Firewall Interference – Some cloud hosting providers implement strict firewall rules by default. Adjust settings in both your firewall and hosting control panel to allow VPN traffic.

Conclusion

A managed firewall is essential for securing your business, protecting your servers, and ensuring smooth network operations. However, misconfigurations, software updates, and network changes can introduce problems.

By following these troubleshooting steps, you can quickly identify and resolve firewall issues before they disrupt your business. If problems persist, consider upgrading to a more advanced firewall solution or consulting with your hosting provider for better integration and security support.

Security is an ongoing process—keep monitoring logs, updating rules, and refining your firewall settings to stay ahead of evolving threats.