AI agents use update_vlan 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 modifies VLAN metadata (description field) on a firewall. While the change is reversible and does not delete data, it alters network configuration state. The severity is medium because misconfiguration could disrupt network operations, but the blast radius is limited to VLAN metadata rather than network traffic flow or security rules.
From the tool's definition Tool name 'update_vlan' combined with description 'Update VLAN description' indicates modification of network configuration data. The action is reversible (updating a description can be undone by updating it again).
Documented attack patterns abuse exactly the kind of access update_vlan 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 update_vlan:
{
"version": "1",
"default": "deny",
"tools": {
"update_vlan": {
"limits": [
{
"counter": "update_vlan_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}update_vlan 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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Update VLAN description. 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 update_vlan: 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.
update_vlan 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 update_vlan 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 update_vlan. 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.
update_vlan 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.