Query MX records (mail exchange servers) for a domain
AI agents call query_mx_record to retrieve information from DNS MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
MX record queries retrieve publicly available DNS information about mail servers for a domain. This is a standard DNS lookup operation with no side effects, no data modification, and no ability to execute code or commands. The tool only reads existing DNS records, making it a Read category risk with minimal severity.
From the tool's definition Tool name 'query_mx_record' and description 'Query MX records (mail exchange servers) for a domain' indicate a read-only DNS query operation with no modification, deletion, or execution of external commands.
Attacks that exploit this kind of access
Query MX records (mail exchange servers) for a domain. It is categorised as a Read tool in the DNS MCP Server MCP Server, which means it retrieves data without modifying state.
Register the DNS MCP Server MCP server in PolicyLayer and add a rule for query_mx_record: 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 DNS MCP Server. Nothing to install.
query_mx_record 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 query_mx_record 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 query_mx_record. 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.
query_mx_record is provided by the DNS MCP Server MCP server (stanibaj/dns-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
query_mx_record is one line of DNS MCP Server's registry record.
The record carries the whole server: verified identity, auth posture, risk grade, every tool classified, recommended policy — re-checked continuously.
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