AI agents call get_firewall_rule to retrieve information from OPNSense MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool queries and retrieves firewall rule information without creating, modifying, deleting, or executing any rules. It has no side effects and presents minimal risk even if misused—an AI agent can only read existing firewall configurations, which may reveal security policies but cannot alter or enforce them.
From the tool's definition Tool name 'get_firewall_rule' and description 'Get firewall rule details' indicate retrieval of existing firewall rule configuration with no modification or execution.
Documented attack patterns abuse exactly the kind of access get_firewall_rule 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 get_firewall_rule:
{
"version": "1",
"default": "deny",
"tools": {
"get_firewall_rule": {}
}
}get_firewall_rule is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Get firewall rule details. It is categorised as a Read tool in the OPNSense MCP Server MCP Server, which means it retrieves data without modifying state.
Register the OPNSense MCP Server MCP server in PolicyLayer and add a rule for get_firewall_rule: 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.
get_firewall_rule is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the get_firewall_rule 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 get_firewall_rule. 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.
get_firewall_rule 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.