Firewall misconfiguration risks

6 min read · Updated February 06, 2026

Common misconfigurations we see and how they turn into downtime or breaches.

Misconfigurations that cause outages

Most firewall outages come from small changes without validation or rollback planning.

• Overly broad NAT changes
• Unintended policy ordering impacts
• Asymmetric routing and missing return paths
• VPN changes without staged testing

Misconfigurations that increase breach risk

These issues often sit quietly until something bad happens.

• Any/Any rules “temporarily” left in place
• Exposed management interfaces
• No MFA for VPN
• Lack of egress filtering

A simple review checklist

A quarterly firewall review catches most issues early.

• Confirm admin access + MFA + logging
• Review inbound rules and remove exceptions
• Validate VPN user groups and least privilege
• Test failover and confirm backups of config

Want help applying this? Email info@1-1solutions.com with your user count, locations, and current platforms.

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