# dns_security

DNS: resolver audit, DNSSEC check, tunneling detection, domain blocklists, query log audit

Agent View of the PolicyLayer registry record for `dns_security`. HTML page: https://policylayer.com/tools/defense/dns-security

## Facts

- Tool: `dns_security`
- Server: Defense (`defense-mcp-server`) — https://policylayer.com/tools/defense.md
- Install: `npx -y defense-mcp-server`
- Homepage: git+https://github.com/bottobot/defense-mcp-server.git
- Risk category: Read (Low risk)
- Registry record: grade F, identity unverified
- Server rate-limited: no
- Parameters: 8 (1 required)
- Recommended policy verdict: Allowed

## Parameters

| Parameter | Type | Required | Description |
| --- | --- | --- | --- |
| `action` | string | yes | DNS security action |
| `domain` | string | no | Domain to check |
| `duration` | number | no | Capture duration in seconds (max 120) |
| `log_path` | string | no | Path to DNS query log |
| `interface` | string | no | Network interface for capture |
| `threshold` | number | no | Entropy threshold for tunneling detection |
| `blocklist_path` | string | no | Path to blocklist file |
| `domains_to_block` | array | no | Domains to add to blocklist |

Parameters from the server's own tool schema.

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "dns_security",
    "arguments": {
      "action": "<action>"
    }
  }
}
```

## 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 own 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."

## Use case

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.

## Recommended policy (PolicyLayer)

Verdict: **Allowed**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches Defense:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "dns_security": {}
  }
}
```

## Other tools on Defense (30)

- `app_harden` — Execute — https://policylayer.com/tools/defense/app-harden.md
- `container_isolation` — Execute — https://policylayer.com/tools/defense/container-isolation.md
- `crypto` — Execute — https://policylayer.com/tools/defense/crypto.md
- `ebpf` — Execute — https://policylayer.com/tools/defense/ebpf.md
- `firewall` — Execute — https://policylayer.com/tools/defense/firewall.md
- `harden_kernel` — Execute — https://policylayer.com/tools/defense/harden-kernel.md
- `honeypot_manage` — Execute — https://policylayer.com/tools/defense/honeypot-manage.md
- `incident_response` — Execute — https://policylayer.com/tools/defense/incident-response.md
- `malware` — Execute — https://policylayer.com/tools/defense/malware.md
- `sudo_session` — Execute — https://policylayer.com/tools/defense/sudo-session.md
- `vuln_manage` — Execute — https://policylayer.com/tools/defense/vuln-manage.md
- `waf_manage` — Execute — https://policylayer.com/tools/defense/waf-manage.md
- `wireless_security` — Execute — https://policylayer.com/tools/defense/wireless-security.md
- `zero_trust` — Execute — https://policylayer.com/tools/defense/zero-trust.md
- `api_security` — Read — https://policylayer.com/tools/defense/api-security.md
- `cloud_security` — Read — https://policylayer.com/tools/defense/cloud-security.md
- `secrets` — Read — https://policylayer.com/tools/defense/secrets.md
- `access_control` — Write — https://policylayer.com/tools/defense/access-control.md
- `backup` — Write — https://policylayer.com/tools/defense/backup.md
- `compliance` — Write — https://policylayer.com/tools/defense/compliance.md
- `container_docker` — Write — https://policylayer.com/tools/defense/container-docker.md
- `defense_mgmt` — Write — https://policylayer.com/tools/defense/defense-mgmt.md
- `harden_host` — Write — https://policylayer.com/tools/defense/harden-host.md
- `integrity` — Write — https://policylayer.com/tools/defense/integrity.md
- `log_management` — Write — https://policylayer.com/tools/defense/log-management.md
- `network_defense` — Write — https://policylayer.com/tools/defense/network-defense.md
- `patch` — Write — https://policylayer.com/tools/defense/patch.md
- `process_security` — Write — https://policylayer.com/tools/defense/process-security.md
- `supply_chain` — Write — https://policylayer.com/tools/defense/supply-chain.md
- `threat_intel` — Write — https://policylayer.com/tools/defense/threat-intel.md

## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

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Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=defense · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/defense