AI agents invoke cli_check_nfs to trigger actions in OPNSense MCP Server. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.
The tool executes a connectivity check, which involves running network diagnostic commands from the DMZ zone. This is an Execute-category action as it triggers external operations. Severity is medium because it involves probing network services from a sensitive network segment (DMZ), and misuse could reveal network topology or be used as a reconnaissance step.
From the tool's definition 'Check NFS connectivity from DMZ' implies running a network connectivity test (e.g., ping, mount, or similar diagnostic command) from a specific network segment (DMZ)
Documented attack patterns abuse exactly the kind of access cli_check_nfs gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and OPNSense MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for cli_check_nfs:
{
"version": "1",
"default": "deny",
"tools": {
"cli_check_nfs": {
"limits": [
{
"counter": "cli_check_nfs_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}cli_check_nfs 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.
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Check NFS connectivity from DMZ. It is categorised as a Execute tool in the OPNSense MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the OPNSense MCP Server MCP server in PolicyLayer and add a rule for cli_check_nfs: 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 OPNSense MCP Server. Nothing to install.
cli_check_nfs is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the cli_check_nfs 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 cli_check_nfs. 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.
cli_check_nfs is provided by the OPNSense MCP Server MCP server (vespo92/opnsensemcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 196 OPNSense MCP Server tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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196 OPNSense MCP Server tools catalogued and risk-classified — across an index of 42,500+ MCP servers.