AI agents call dns_lookup to retrieve information from Basic without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
DNS lookup is a read-only operation that queries the Domain Name System to retrieve IP address information associated with a hostname. It has no side effects, does not modify data, and does not execute code or trigger external operations beyond the lookup itself.
From the tool's definition Tool description states 'Perform DNS lookup for a hostname.' DNS lookups retrieve network information without modifying, deleting, or executing arbitrary code. The operation is a standard query that returns data about domain name resolution.
Attacks that exploit this kind of access
Perform DNS lookup for a hostname. It is categorised as a Read tool in the Basic MCP Server, which means it retrieves data without modifying state.
Register the Basic 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 Basic. Nothing to install.
dns_lookup is a Read tool with low risk. Read-only tools are generally safe to allow by default.
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.
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.
dns_lookup is provided by the Basic MCP server (msilverblatt/basic-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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