Reverse NS lookup. Find all gTLD domains hosted on a specific nameserver. Useful for mapping domain portfolios, understanding the scale of a nameserver's usage, and discovering what domains share infrastructure. Best practices: - sort=length_asc surfaces the shortest (most premium) domains first ...
Risk signalsHigh parameter count (11 properties)
Part of the DomainKits server.
Free to start. No card required.
AI agents invoke ns_reverse to trigger processes or run actions in DomainKits. Execute operations can have side effects beyond the immediate call -- triggering builds, sending notifications, or starting workflows. Rate limits and argument validation are essential to prevent runaway execution.
ns_reverse can trigger processes with real-world consequences. An uncontrolled agent might start dozens of builds, send mass notifications, or kick off expensive compute jobs. PolicyLayer enforces rate limits and validates arguments to keep execution within safe bounds.
Execute tools trigger processes. Rate-limit and validate arguments to prevent unintended side effects.
{
"version": "1",
"default": "deny",
"tools": {
"ns_reverse": {
"limits": [
{
"counter": "ns_reverse_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}See the full DomainKits policy for all 38 tools.
These attack patterns abuse exactly the kind of access ns_reverse gives an agent. Each links to the full case and the policy that stops it:
Other execute tools across the catalogue. The same approach applies to each: rate-limit and validate the arguments.
Reverse NS lookup. Find all gTLD domains hosted on a specific nameserver. Useful for mapping domain portfolios, understanding the scale of a nameserver's usage, and discovering what domains share infrastructure. Best practices: - sort=length_asc surfaces the shortest (most premium) domains first — large portfolios often contain hidden short-letter gems. - pure_alpha=true is the cleanest way to filter for letter-only domains. This is stricter than no_number + no_hyphen combined, as it excludes any non-letter character. - keyword filters by substring within domain names on that nameserver — useful for finding domains in a specific niche or vertical. - min_len and max_len require exact integers (e.g., '4'), not range syntax like '<5'. - If results fill a full page (10+), check total and paginate — large nameservers may host thousands of domains. - Look for patterns in results: similar naming conventions (brand-us.com, brand-uk.com) indicate portfolio clustering by the same owner.. It is categorised as a Execute tool in the DomainKits MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the DomainKits MCP server in PolicyLayer and add a rule for ns_reverse: 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 DomainKits. Nothing to install.
ns_reverse is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the ns_reverse 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 ns_reverse. 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.
ns_reverse is provided by the DomainKits MCP server (https://api.domainkits.com/v1/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 38 DomainKits tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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