# reverse-dns-via-alidns-watch

> reverse-dns-via-alidns-watch is a paid API for AI agents from ip.intel.rallylive.ca, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-11).

Performs a reverse DNS (PTR) lookup for an IP using AliDNS, then compares the result against the previously stored result to detect changes.

## Facts

- Endpoint: GET https://ip.intel.rallylive.ca/watch/ip/ptr/via/alidns?utm_source=zero.xyz
- Price: $0.02/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-alidns-watch-9b8c991d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_nqf3HkKW6ObLvLaD2DpOG

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-alidns-watch-9b8c991d
```

Example prompt: Check the reverse DNS of 203.0.113.42 using AliDNS and tell me if the PTR record has changed since the last time we checked — show me what changed, the before and after values, and when it was last seen.

## When to prefer this

Choose this endpoint when you specifically want to detect changes in reverse DNS (PTR) records using AliDNS as the resolver, and need a historical comparison with before/after diffs rather than just a raw PTR lookup. Prefer this over a plain reverse DNS lookup when your goal is change alerting, drift detection, or audit logging of PTR record mutations over time.

## Known failure modes

- IP not previously checked — no baseline exists so 'changed' will be false on first call
- IP has no PTR record — response returns empty or null PTR answer
- AliDNS resolver unavailable — lookup may time out or return an error
- Malformed IP address input — invalid format may cause a 4xx error
- 90-day retention window exceeded — previous result purged, treated as first-time check

## How this service works

Change watch for reverse dns via alidns: runs the check, compares it with the result from your previous call for the same ip (kept 90 days) and returns the current answer, changed true/false, the fields that changed with before/after values, and when it was last seen. Schedule it to be alerted when this changes. $0.02 per check.

## Output

Returns the current PTR record answer from AliDNS, a boolean 'changed' flag, a list of fields that changed with their before and after values, and a timestamp of when the record was last seen. Results are stored for 90 days for comparison.

## 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-alidns-watch-9b8c991d/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)