no_portscan · Nmap MCP: Risk & Policy

WHAT IT DOES

What no_portscan does on NmapMCP

AI agents invoke no_portscan to trigger actions in NmapMCP. 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 no_portscan needs a policy

This tool performs active network reconnaissance (host discovery) against a specified target. While it doesn't scan ports, it still executes outbound network probes to discover live hosts. This is an external operation whose effects depend on the target argument, fitting the Execute category. Misuse could facilitate unauthorized reconnaissance of networks, hence medium severity.

From the tool's definition 'Perform host discovery without port scanning on the specified target' — actively probes/scans a network target, triggering external network operations

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

no_portscan Rate-limited

no_portscan 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": {
    "no_portscan": {
      "limits": [
        {
          "counter": "no_portscan_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 NmapMCP, so you can run agents against it safely.

FAQ

Questions about no_portscan

What does the no_portscan tool do? +

Perform host discovery without port scanning on the specified target with optional custom arguments. It is categorised as a Execute tool in the NmapMCP MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on no_portscan? +

Register the Nmap MCP server in PolicyLayer and add a rule for no_portscan: 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 NmapMCP. Nothing to install.

What risk level is no_portscan? +

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

Can I rate-limit no_portscan? +

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

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

no_portscan is provided by the Nmap MCP server (0xpratikpatil/nmapmcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.