# reverse-dns-via-cleanbrowsing

> reverse-dns-via-cleanbrowsing is a paid API for AI agents from ip.intel.rallylive.ca, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-11).

Performs a reverse DNS (PTR) lookup for an IPv4 address using CleanBrowsing's security-filtered resolver, returning hostname(s), TTL, response code, and forward-confirmed reverse DNS (FCrDNS) status.

## Facts

- Endpoint: GET https://ip.intel.rallylive.ca/ip/ptr/via/cleanbrowsing?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-11
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/reverse-dns-via-cleanbrowsing-1206359b
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_cxR_HFfiJ8S0Ci28Ok3Pd

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability reverse-dns-via-cleanbrowsing-1206359b
```

Example prompt: What hostname does CleanBrowsing return for the reverse DNS of 8.8.8.8, and does the PTR record forward-confirm back to that IP?

## When to prefer this

Choose this endpoint when you specifically want to see how CleanBrowsing's security-filtered DNS resolver answers PTR queries — useful for diagnosing whether a security filter is suppressing or altering reverse DNS results, verifying FCrDNS for email deliverability checks, or comparing resolver behavior across providers. Prefer this over generic PTR lookups when CleanBrowsing's perspective (security filtering) is the distinguishing factor.

## Known failure modes

- IP not in valid IPv4 format returns an error or empty response
- CleanBrowsing may filter or block certain PTR records, returning NXDOMAIN or SERVFAIL even if a PTR exists on other resolvers
- No PTR record configured for the IP results in NXDOMAIN response
- FCrDNS check fails if the hostname's A record does not resolve back to the queried IP
- Network timeout contacting CleanBrowsing resolvers may result in a SERVFAIL response

## How this service works

Reverse DNS (PTR) of an IPv4 address as answered by CleanBrowsing (security filter): the hostname(s), TTL and response code, plus whether the PTR's forward A record points back (forward-confirmed reverse DNS). Compare resolvers for stale or filtered answers. $0.01 per lookup.

## Output

Returns the PTR hostname(s) associated with the queried IPv4 address as resolved by CleanBrowsing, along with the DNS TTL, DNS response code (e.g. NOERROR, NXDOMAIN, SERVFAIL), and a boolean indicating whether the PTR record is forward-confirmed (i.e. the resolved hostname's A record points back to the original IP).

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {}
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/reverse-dns-via-cleanbrowsing-1206359b/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from ip.intel.rallylive.ca](https://www.zero.xyz/host/ip.intel.rallylive.ca/llms.txt)