AI agents call find_arp_by_interface 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 Address Resolution Protocol (ARP) entries from a network interface without creating, modifying, or deleting any data. It is a read-only operation that returns network state information for diagnostic or informational purposes. The blast radius of misuse is minimal—an attacker could only gain visibility into network mappings already present on the system.
From the tool's definition Tool name 'find_arp_by_interface' and description 'Find ARP entries on specific interface' indicate retrieval of ARP table data with no modification capability.
Documented attack patterns abuse exactly the kind of access find_arp_by_interface 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 find_arp_by_interface:
{
"version": "1",
"default": "deny",
"tools": {
"find_arp_by_interface": {}
}
}find_arp_by_interface is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Find ARP entries on specific interface. 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 find_arp_by_interface: 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.
find_arp_by_interface 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 find_arp_by_interface 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 find_arp_by_interface. 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.
find_arp_by_interface 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.