enable_firewall · Firegex MCP: Risk & Policy

WHAT IT DOES

What enable_firewall does on Firegex

AI agents invoke enable_firewall to trigger actions in Firegex. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why enable_firewall needs a policy

This tool triggers an external system operation — enabling a kernel-level nftables firewall — which can immediately affect network traffic filtering across potentially all connections. It is not a simple write (data creation/modification) but an execution of a system-level action with broad blast radius. Misuse by an AI agent could block legitimate traffic or expose services depending on the ruleset being activated.

From the tool's definition "Activate the nftables firewall ruleset"

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

enable_firewall Rate-limited

enable_firewall stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "enable_firewall": {
      "limits": [
        {
          "counter": "enable_firewall_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Firegex, so you can run agents against it safely.

FAQ

Questions about enable_firewall

What does the enable_firewall tool do? +

Activate the nftables firewall ruleset. It is categorised as a Execute tool in the Firegex MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on enable_firewall? +

Register the Firegex MCP server in PolicyLayer and add a rule for enable_firewall: 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 Firegex. Nothing to install.

What risk level is enable_firewall? +

enable_firewall is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit enable_firewall? +

Yes. Add a rate_limit block to the enable_firewall 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 enable_firewall completely? +

Set action: deny in the PolicyLayer policy for enable_firewall. 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 enable_firewall? +

enable_firewall is provided by the Firegex MCP server (umbra2728/firegex-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.