dns_security
DNS: resolver audit, DNSSEC check, tunneling detection, domain blocklists, query log audit
This record as markdown: /tools/defense/dns-security.md
What dns_security does on Defense
AI agents call dns_security to retrieve information from Defense without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
| Parameter | Type | Required | Description |
|---|---|---|---|
action | string | Yes | DNS security action |
domain | string | — | Domain to check |
duration | number | — | Capture duration in seconds (max 120) |
log_path | string | — | Path to DNS query log |
interface | string | — | Network interface for capture |
threshold | number | — | Entropy threshold for tunneling detection |
blocklist_path | string | — | Path to blocklist file |
domains_to_block | array | — | Domains to add to blocklist |
Parameters from the server's own tool schema.
Why dns_security is rated Low
This tool performs reconnaissance and diagnostic checks on DNS infrastructure: auditing resolvers, validating DNSSEC records, examining logs, and checking against blocklists. These are read-only, informational security operations that retrieve and analyze data without modifying DNS configuration, executing commands, or triggering external side effects.
From the tool's definition Tool functions are described as: 'resolver audit', 'DNSSEC check', 'tunneling detection', 'domain blocklists', 'query log audit' — all query, inspection, and audit operations with no modification, deletion, or execution of external operations.
Attacks that exploit this kind of access
The rule that runs dns_security safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Defense, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For dns_security, this is the rule to start with:
dns_security is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Defense, apply this rule, and every dns_security call is checked against it from then on.
Questions about dns_security
DNS: resolver audit, DNSSEC check, tunneling detection, domain blocklists, query log audit. It is categorised as a Read tool in the Defense MCP Server, which means it retrieves data without modifying state.
dns_security accepts 8 parameters: action, domain, duration, log_path, interface, threshold, blocklist_path, domains_to_block. Required: action. The full parameter table on this page comes from the server's own tool schema.
Register the Defense MCP server in PolicyLayer and add a rule for dns_security: 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 Defense. Nothing to install.
dns_security 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_security 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_security. 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_security is provided by the Defense MCP server (defense-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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