Set NAT mode (automatic, hybrid, manual, disabled)
AI agents use nat_set_mode to create or update resources in OPNSense MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your OPNSense MCP Server environment.
This tool creates or modifies firewall NAT configuration settings reversibly. Setting NAT mode is a Write operation that changes network behavior and routing rules. The impact is high because incorrect NAT mode settings can disrupt network connectivity, traffic flow, and security posture across the entire firewall, affecting all downstream clients and services, though changes are reversible if corrected.
From the tool's definition Tool named 'nat_set_mode' with description 'Set NAT mode (automatic, hybrid, manual, disabled)' modifies firewall NAT configuration, which is a persistent network setting.
Documented attack patterns abuse exactly the kind of access nat_set_mode 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 nat_set_mode:
{
"version": "1",
"default": "deny",
"tools": {
"nat_set_mode": {
"limits": [
{
"counter": "nat_set_mode_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}nat_set_mode stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
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Set NAT mode (automatic, hybrid, manual, disabled). It is categorised as a Write tool in the OPNSense MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the OPNSense MCP Server MCP server in PolicyLayer and add a rule for nat_set_mode: 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.
nat_set_mode is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the nat_set_mode 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 nat_set_mode. 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.
nat_set_mode 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.
Free to start. No card required.
196 OPNSense MCP Server tools catalogued and risk-classified — across an index of 42,500+ MCP servers.