dns_flush_blocked

THE RISK

Critical Risk

Why dns_flush_blocked needs a policy

This tool irreversibly removes all manually blocked domains from the block list. 'Flush the entire custom block list' and 'All manually blocked domains will be removed' indicate a bulk, potentially irreversible deletion of security policy data. Removing all blocked domains could expose the network to previously blocked malicious domains, representing a high blast radius if misused.

From the tool's definition Flush the entire custom block list. All manually blocked domains will be removed.

Risk signalsBulk/mass operation — affects multiple targets

Documented attack patterns abuse exactly the kind of access dns_flush_blocked gives an agent:

POLICY

How to control dns_flush_blocked

PolicyLayer is an MCP gateway — it sits between your AI agents and Technitium MCP Secure, and nothing reaches the server without passing your rules. This is the rule we recommend for dns_flush_blocked:

policy.json

{
  "version": "1",
  "default": "deny",
  "hide": [
    "dns_flush_blocked"
  ]
}

dns_flush_blocked disappears from the agent's tool list entirely, and any attempt to call it is denied. The rest of the server keeps working.

Create a free account and register Technitium MCP Secure — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

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EXPLORE

Related tools and policies

More Technitium MCP Secure tools

Destructive dns_delete_cached Delete a specific domain from the DNS cache. Unlike flush, this only removes the specified Destructive dns_delete_record Delete a specific DNS record from a zone. Requires confirm=true to execute. Destructive dns_delete_zone Delete a DNS zone and all its records. Requires confirm=true to execute. Destructive dns_remove_allowed Remove a domain from the allow list. The domain will no longer bypass block lists. Destructive dns_uninstall_app Uninstall a DNS app from the server. Requires confirm=true to execute. Destructive dns_flush_allowed Flush the entire allow list. All allowed domains will be removed. Requires confirm=true to Execute dns_flush_cache Flush the entire DNS cache. Forces all subsequent queries to be resolved fresh from upstre Execute dns_install_app Download and install a DNS app from the Technitium app store. Use dns_list_app_store to se

All 39 Technitium MCP Secure tools →

Destructive tools on other servers

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Go deeper

Critical-risk tools in Technitium MCP Secure → Every critical-risk tool this server exposes, in one view.
All critical-risk MCP tools → Every critical-risk tool across the catalogue, and the policy pattern that contains them.
The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Blast radius → How much damage one compromised or confused agent can do — and how to bound it.
Tool call approval → Approval gates on individual tool calls: auto-allow, prompt, or deny.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about dns_flush_blocked

What does the dns_flush_blocked tool do? +

Flush the entire custom block list. All manually blocked domains will be removed. Requires confirm=true to execute. It is categorised as a Destructive tool in the Technitium MCP Secure MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.

How do I enforce a policy on dns_flush_blocked? +

Register the Technitium MCP Secure MCP server in PolicyLayer and add a rule for dns_flush_blocked: 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 Technitium MCP Secure. Nothing to install.

What risk level is dns_flush_blocked? +

dns_flush_blocked is a Destructive tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.

Can I rate-limit dns_flush_blocked? +

Yes. Add a rate_limit block to the dns_flush_blocked 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_flush_blocked completely? +

Set action: deny in the PolicyLayer policy for dns_flush_blocked. 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_flush_blocked? +

dns_flush_blocked is provided by the Technitium MCP Secure MCP server (rosschurchill/technitium-mcp-secure). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Technitium MCP Secure tool call.

Start from Technitium MCP Secure, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

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