dns_lookup

Look up DNS records for a hostname. record_type: A, AAAA, MX, TXT, NS, CNAME, PTR, SOA, SRV. nameserver: optional custom resolver IP (e.g., '8.8.8.8' for Google DNS, '1.1.1.1' for Cloudflare).

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/dns-lookup.md

WHAT IT DOES

What dns_lookup does on Mcp Nettools

AI agents call dns_lookup 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 dns_lookup is rated Low

DNS lookup is a standard network diagnostic query that retrieves publicly available DNS information. It has no side effects, cannot modify data, and poses minimal risk even if misused by an AI agent. The tool simply returns DNS resolution results based on the queried hostname and record type.

From the tool's definition Tool description explicitly states 'Look up DNS records' which is a query operation. It retrieves DNS information (A, AAAA, MX, TXT, NS, CNAME, PTR, SOA, SRV records) without modifying any data.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs dns_lookup 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 dns_lookup, this is the rule to start with:

dns_lookup Allowed

dns_lookup 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": {
    "dns_lookup": {}
  }
}

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 dns_lookup call is checked against it from then on.

FAQ

Questions about dns_lookup

What does the dns_lookup tool do? +

Look up DNS records for a hostname. record_type: A, AAAA, MX, TXT, NS, CNAME, PTR, SOA, SRV. nameserver: optional custom resolver IP (e.g., '8.8.8.8' for Google DNS, '1.1.1.1' for Cloudflare). 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 dns_lookup? +

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

What risk level is dns_lookup? +

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

Can I rate-limit dns_lookup? +

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

Set action: deny in the PolicyLayer policy for 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 dns_lookup? +

dns_lookup 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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