opn_haproxy_configtest

THE RISK

High Risk

Why opn_haproxy_configtest needs a policy

This tool runs a configuration syntax validation/test against HAProxy, which is an active execution of a diagnostic check. It doesn't read stored data passively nor write/modify anything — it triggers an external operation (config test run). The blast radius is low since it only validates and does not apply changes.

From the tool's definition Validate HAProxy configuration syntax before applying

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

POLICY

How to control opn_haproxy_configtest

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_haproxy_configtest:

policy.json

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

opn_haproxy_configtest 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.

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.

RATE-LIMIT THIS TOOL →

Free to start. No card required.

EXPLORE

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All 81 OPNsense MCP Server tools →

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Go deeper

High-risk tools in OPNsense MCP Server → Every high-risk tool this server exposes, in one view.
All high-risk MCP tools → Every high-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.
Agent sandbox → Bounding what an agent can execute and where the boundary should sit.
Least privilege for MCP → Granting agents the minimum tool surface the task needs.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about opn_haproxy_configtest

What does the opn_haproxy_configtest tool do? +

Validate HAProxy configuration syntax before applying. It is categorised as a Execute tool in the OPNsense MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on opn_haproxy_configtest? +

Register the OPNsense MCP Server MCP server in PolicyLayer and add a rule for opn_haproxy_configtest: 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_haproxy_configtest? +

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

Can I rate-limit opn_haproxy_configtest? +

Yes. Add a rate_limit block to the opn_haproxy_configtest 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_haproxy_configtest completely? +

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

opn_haproxy_configtest 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 →