Add a DNSBL subscription list (e.g. OISD, Hagezi, Abuse.ch ThreatFox)
AI agents use add_dnsbl_subscription 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 new DNSBL (DNS Block List) subscription entries in the OPNSense firewall configuration. While it modifies firewall behavior, the change is reversible and does not execute arbitrary code or delete data.
From the tool's definition add_dnsbl_subscription adds a DNS blocklist subscription, which creates or modifies the firewall's DNS blocking configuration. The action is reversible (subscriptions can be removed), fitting the Write category.
Documented attack patterns abuse exactly the kind of access add_dnsbl_subscription 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 add_dnsbl_subscription:
{
"version": "1",
"default": "deny",
"tools": {
"add_dnsbl_subscription": {
"limits": [
{
"counter": "add_dnsbl_subscription_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}add_dnsbl_subscription 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.
Free to start. No card required.
Add a DNSBL subscription list (e.g. OISD, Hagezi, Abuse.ch ThreatFox). 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 add_dnsbl_subscription: 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.
add_dnsbl_subscription 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 add_dnsbl_subscription 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 add_dnsbl_subscription. 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.
add_dnsbl_subscription 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.