Medium Risk

block_multiple_domains

Block multiple domains at once

How to control block_multiple_domains ↓

AI agents use block_multiple_domains 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

Blocking multiple domains modifies the firewall's DNS blocklist or firewall rules configuration. This is a write/modify operation on the firewall configuration. While it could be considered Execute (triggering a network operation), it's fundamentally creating/updating blocking rules.

From the tool's definition Block multiple domains at once

Documented attack patterns abuse exactly the kind of access block_multiple_domains 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 block_multiple_domains:

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

block_multiple_domains 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.
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Go deeper

What does the block_multiple_domains tool do? +

Block multiple domains at once. 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 block_multiple_domains? +

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

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

Can I rate-limit block_multiple_domains? +

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

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

block_multiple_domains 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.

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

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