opn_delete_firewall_rule

THE RISK

Critical Risk

Why opn_delete_firewall_rule needs a policy

This tool irreversibly deletes firewall rules from an OPNsense firewall. Deleting security rules cannot be undone without re-creating them and is a destructive action. While the description is empty, the tool name alone clearly indicates destructive intent.

From the tool's definition Tool name is 'opn_delete_firewall_rule' which explicitly performs a delete operation on firewall rules. The verb 'delete' indicates irreversible removal of configuration.

Documented attack patterns abuse exactly the kind of access opn_delete_firewall_rule gives an agent:

POLICY

How to control opn_delete_firewall_rule

PolicyLayer is an MCP gateway — it sits between your AI agents and OPNsense MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for opn_delete_firewall_rule:

policy.json

{
  "version": "1",
  "default": "deny",
  "hide": [
    "opn_delete_firewall_rule"
  ]
}

opn_delete_firewall_rule disappears from the agent's tool list entirely, and any attempt to call it is denied. The rest of the server keeps working.

Create a free account and register OPNsense MCP Server — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

RESTRICT THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More OPNsense MCP Server tools

Destructive opn_delete_alias opn_delete_alias Destructive opn_delete_ddns_account Delete a Dynamic DNS account by UUID and apply the configuration. Destructive opn_delete_dns_override opn_delete_dns_override Destructive opn_delete_dnsmasq_range Delete a dnsmasq DHCP range by UUID and apply the configuration. Destructive opn_delete_firewall_category opn_delete_firewall_category Destructive opn_delete_nat_rule opn_delete_nat_rule Destructive opn_haproxy_delete opn_haproxy_delete Destructive opn_remove_dnsbl_allowlist opn_remove_dnsbl_allowlist

All 81 OPNsense MCP Server tools →

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Go deeper

Critical-risk tools in OPNsense MCP Server → Every critical-risk tool this server exposes, in one view.
All critical-risk MCP tools → Every critical-risk tool across the catalogue, and the policy pattern that contains them.
The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Blast radius → How much damage one compromised or confused agent can do — and how to bound it.
Tool call approval → Approval gates on individual tool calls: auto-allow, prompt, or deny.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about opn_delete_firewall_rule

What does the opn_delete_firewall_rule tool do? +

opn_delete_firewall_rule. It is categorised as a Destructive tool in the OPNsense MCP Server MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.

How do I enforce a policy on opn_delete_firewall_rule? +

Register the OPNsense MCP Server MCP server in PolicyLayer and add a rule for opn_delete_firewall_rule: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches OPNsense MCP Server. Nothing to install.

What risk level is opn_delete_firewall_rule? +

opn_delete_firewall_rule is a Destructive tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.

Can I rate-limit opn_delete_firewall_rule? +

Yes. Add a rate_limit block to the opn_delete_firewall_rule rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block opn_delete_firewall_rule completely? +

Set action: deny in the PolicyLayer policy for opn_delete_firewall_rule. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides opn_delete_firewall_rule? +

opn_delete_firewall_rule is provided by the OPNsense MCP Server MCP server (lucamarien/opnsense-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every OPNsense MCP Server tool call.

Start from OPNsense MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →