dns_flush_cache

THE RISK

High Risk

Why dns_flush_cache needs a policy

This tool executes a command that modifies system state by clearing cached DNS records. While not destructive (the cache can be repopulated), it's Execute rather than Write because it triggers an active operation with broad external effects (all subsequent queries affected) rather than creating/modifying a discrete data entity.

From the tool's definition 'Flush the entire DNS cache' - performs a system-wide operation that forces all subsequent queries to be resolved fresh from upstream. This is an executable action that triggers external operational effects on the DNS server's cache state.

Risk signalsBulk/mass operation — affects multiple targets

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

POLICY

How to control dns_flush_cache

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_cache:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "dns_flush_cache": {
      "limits": [
        {
          "counter": "dns_flush_cache_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

dns_flush_cache stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

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.

RATE-LIMIT THIS TOOL →

Free to start. No card required.

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 Destructive dns_flush_blocked Flush the entire custom block list. All manually blocked domains will be removed. Requires 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 →

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Go deeper

High-risk tools in Technitium MCP Secure → Every high-risk tool this server exposes, in one view.
All high-risk MCP tools → Every high-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.
Agent sandbox → Bounding what an agent can execute and where the boundary should sit.
Least privilege for MCP → Granting agents the minimum tool surface the task needs.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about dns_flush_cache

What does the dns_flush_cache tool do? +

Flush the entire DNS cache. Forces all subsequent queries to be resolved fresh from upstream. Requires confirm=true to execute. It is categorised as a Execute tool in the Technitium MCP Secure MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on dns_flush_cache? +

Register the Technitium MCP Secure MCP server in PolicyLayer and add a rule for dns_flush_cache: 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_cache? +

dns_flush_cache is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit dns_flush_cache? +

Yes. Add a rate_limit block to the dns_flush_cache 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_cache completely? +

Set action: deny in the PolicyLayer policy for dns_flush_cache. 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_cache? +

dns_flush_cache 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.

CHECK YOUR STACK →