Medium Risk

haproxy_acl_create

Create an ACL for HAProxy frontend. Supports all OPNsense HAProxy ACL expression types including SNI matching for TCP/SSL passthrough.

How to control haproxy_acl_create ↓

AI agents use haproxy_acl_create to create or update resources in OPNSense MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your OPNSense MCP Server environment.

Medium Risk

This tool creates Access Control Lists (ACLs) in HAProxy, which are configurations that control network traffic routing and filtering. Creating ACLs modifies firewall behavior reversibly—new rules can be updated or removed—making this a Write operation.

From the tool's definition Tool name 'haproxy_acl_create' and description 'Create an ACL for HAProxy frontend' indicate creation of firewall/proxy access control rules that modify HAProxy configuration.

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

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 haproxy_acl_create:

policy.json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "haproxy_acl_create": {
      "limits": [
        {
          "counter": "haproxy_acl_create_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

haproxy_acl_create stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

  1. Create a free account and register OPNSense MCP Server — nothing to install.
  2. Add this policy — paste it, or build it visually.
  3. Point your MCP client (Claude, Cursor, anything) at your gateway URL.
LIMIT THIS TOOL →

Free to start. No card required.

Go deeper

What does the haproxy_acl_create tool do? +

Create an ACL for HAProxy frontend. Supports all OPNsense HAProxy ACL expression types including SNI matching for TCP/SSL passthrough. It is categorised as a Write tool in the OPNSense MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on haproxy_acl_create? +

Register the OPNSense MCP Server MCP server in PolicyLayer and add a rule for haproxy_acl_create: 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 haproxy_acl_create? +

haproxy_acl_create is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit haproxy_acl_create? +

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

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

haproxy_acl_create is provided by the OPNSense MCP Server MCP server (vespo92/opnsensemcp). 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.

Deterministic rules across all 196 OPNSense MCP Server tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.

Free to start. No card required.

196 OPNSense MCP Server tools catalogued and risk-classified — across an index of 42,500+ MCP servers.

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