opn_dns_lookup

THE RISK

Low Risk

Why opn_dns_lookup needs a policy

DNS lookup is a fundamental read operation that queries DNS records and returns results without side effects. Even in a firewall management context, a lookup tool retrieves data only. The empty description reduces confidence slightly, but the tool name strongly suggests read-only functionality.

From the tool's definition Tool name 'opn_dns_lookup' indicates a DNS query/lookup operation, which retrieves information without modifying state.

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

POLICY

How to control opn_dns_lookup

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_dns_lookup:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "opn_dns_lookup": {}
  }
}

opn_dns_lookup is read-only, so it stays allowed — but 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.

CAP 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_firewall_rule opn_delete_firewall_rule Destructive opn_delete_nat_rule opn_delete_nat_rule Destructive opn_haproxy_delete opn_haproxy_delete

All 81 OPNsense MCP Server tools →

Read tools on other servers

M-Team MCP Server get_torrent_detail YouTube MCP Server search_channel Android Forensics ADB MCP Server parse_browser_history 0xarchive web3_challenge

Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Data exfiltration → How read access becomes an exfiltration channel when chained with untrusted content.
MCP token cost → What connecting this server costs in context-window tokens on every request.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about opn_dns_lookup

What does the opn_dns_lookup tool do? +

opn_dns_lookup. It is categorised as a Read tool in the OPNsense MCP Server MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on opn_dns_lookup? +

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

opn_dns_lookup is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit opn_dns_lookup? +

Yes. Add a rate_limit block to the opn_dns_lookup 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_dns_lookup completely? +

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

opn_dns_lookup 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 →