reverse_dns

Reverse DNS lookup for an IP address — returns the PTR hostname.

SERVERMcp Nettools SOURCEaaronckj/mcp-nettools

Low RISK CLASS

Category Read

Parameters 00 required

Recommended Allowedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/aaronckj-mcp-nettools/reverse-dns.md

WHAT IT DOES

What reverse_dns does on Mcp Nettools

AI agents call reverse_dns to retrieve information from Mcp Nettools without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

RISK

Why reverse_dns is rated Low

Reverse DNS lookup is a read-only network query that resolves an IP address to its associated hostname via PTR records. It has no capability to modify data, execute commands, delete information, or affect financial systems. The only risk is potential information disclosure about network infrastructure, which is low-severity since DNS information is often publicly available.

From the tool's definition Tool performs a 'reverse DNS lookup' which 'returns the PTR hostname' — a query operation that retrieves data without modification or side effects.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs reverse_dns safely

PolicyLayer is an MCP gateway: it sits between your AI agents and Mcp Nettools, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For reverse_dns, this is the rule to start with:

reverse_dns Allowed

reverse_dns is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

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

ALLOW ONLY THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect Mcp Nettools, apply this rule, and every reverse_dns call is checked against it from then on.

FAQ

Questions about reverse_dns

What does the reverse_dns tool do? +

Reverse DNS lookup for an IP address — returns the PTR hostname. It is categorised as a Read tool in the Mcp Nettools MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on reverse_dns? +

Register the Mcp Nettools MCP server in PolicyLayer and add a rule for reverse_dns: 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 Mcp Nettools. Nothing to install.

What risk level is reverse_dns? +

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

Can I rate-limit reverse_dns? +

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

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

reverse_dns is provided by the Mcp Nettools MCP server (aaronckj/mcp-nettools). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

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