# SiteCheck Web Intel NTP Port 123 Passive Scan Lookup

> SiteCheck Web Intel NTP Port 123 Passive Scan Lookup is a paid API for AI agents from api.webintel-api.workers.dev, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-24).

Checks Shodan's passive scan data to determine whether port 123 (NTP) has been observed open on a given IPv4 address

## Facts

- Endpoint: GET https://api.webintel-api.workers.dev/api/security/ntp-monlist-audit?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-24
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/sitecheck-web-intel-ntp-port-123-passive-scan-lookup-ec41cd8e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_cNkvRi8J38CU6f3IMPY0v

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 sitecheck-web-intel-ntp-port-123-passive-scan-lookup-ec41cd8e
```

Example prompt: Can you check Shodan's passive scan data to see if port 123 (NTP) has been observed open on the IP address 129.6.15.28?

## When to prefer this

Use this endpoint when you need a fast, passive check of whether NTP (port 123) is exposed on a given IPv4 address using Shodan's historical data, without triggering any active probe. Prefer this over active scanners when stealth or non-intrusiveness is required. Note: this cannot confirm whether monlist amplification is enabled — only that port 123 was observed open at some point in Shodan's data.

## Known failure modes

- Invalid or malformed IPv4 address returns an error
- IPv6 addresses are not supported
- Shodan may have no data for the IP, returning no port observation
- Data may be stale if Shodan has not recently scanned the IP
- Private or RFC1918 addresses may return no results
- Rate limiting or payment failure may block the request

## How this service works

Reports whether Shodan's pre-collected passive scan data shows NTP (port 123) seen open on an IPv4 address. Passive and possibly old; the monlist amplification check itself is not run, so this cannot say whether monlist is enabled.

## Output

Returns whether Shodan's pre-collected passive scan data shows port 123 (NTP) as having been observed open on the specified IPv4 address. Note: this reflects historical passive data and does not perform a live scan or test for monlist amplification vulnerability — only port visibility is reported.

## 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",
     "required": [
      "ip"
     ],
     "properties": {
      "ip": {
       "type": "string",
       "description": "IPv4 address such as 129.6.15.28 (required)"
      }
     }
    }
   },
   "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/sitecheck-web-intel-ntp-port-123-passive-scan-lookup-ec41cd8e/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.webintel-api.workers.dev](https://www.zero.xyz/host/api.webintel-api.workers.dev/llms.txt)