OPNsense Firewall Audit

Perform a security audit of the OPNsense firewall configuration.

Keywords

audit, firewall, review rules, security check, firewall review, permissive, rules audit, security audit

When to Use

• User asks to audit or review firewall rules
• User asks for a security check of the firewall
• User wants to know if any rules are too permissive
• User asks about firewall configuration quality

Workflow

Step 1: Gather Firewall Configuration (run in parallel)

1. opnsense_fw_list_rules — all filter rules
2. opnsense_fw_list_aliases — all aliases (host groups, networks, ports)

Step 2: Analyze Rules

Check for these security concerns:

Critical

• Rules with source=any AND destination=any AND action=pass (allow-all)
• Rules with protocol=any AND no port restrictions
• Pass rules on WAN interface with no source restrictions

Warning

• Disabled rules that were previously active (may indicate incomplete cleanup)
• Rules with very broad source/destination (e.g., entire /8 networks)
• Multiple rules that could be consolidated into alias-based rules

Info

• Total rule count per interface
• Rules without descriptions (poor documentation)
• Alias usage vs inline addresses

Step 3: Check Active State

1. opnsense_diag_fw_states — active connection states (look for unexpected connections)
2. opnsense_diag_fw_logs (limit: 200) — recent blocks (look for patterns)

Step 4: Report

## Firewall Audit Report

### Summary
- Total rules: {count}
- Enabled: {count} | Disabled: {count}
- Aliases: {count}
- Active states: {count}

### Critical Findings
{List critical issues with rule details and remediation}

### Warnings
{List warnings with context}

### Informational
{List info items}

### Blocked Traffic Patterns (Last 200 Entries)
- Top blocked sources: {list}
- Top blocked destinations: {list}
- Top blocked ports: {list}

### Recommendations
1. {Prioritized action items}

Important

• This skill is READ-ONLY — it never modifies firewall rules
• If the user asks to fix an issue found during audit, switch to manual rule management (not this skill)
• Present findings objectively — let the user decide on remediation
• An empty rule set is not necessarily a problem (OPNsense has implicit deny-all)