# is-port-25-open

> is-port-25-open is a paid API for AI agents from ip.intel.rallylive.ca, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-13).

Checks whether TCP port 25 (SMTP) is open, closed, or filtered on a given host by attempting a connection from Cloudflare's edge network.

## Facts

- Endpoint: GET https://ip.intel.rallylive.ca/ip/port/25?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/is-port-25-open-d116db94
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Syh3JFtv04OAu6eKe4197

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 is-port-25-open-d116db94
```

Example prompt: Can you check whether TCP port 25 (SMTP) is open or closed on mail.example.com? I want to know if the mail server is exposed without running a scanner myself.

## When to prefer this

Use this endpoint when you need a quick, external vantage-point check of whether TCP port 25 (SMTP) is open on a host without deploying your own scanner. It is especially useful for security audits, mail server setup verification, and deliverability troubleshooting. Prefer this over generic port scanners when you want a lightweight, pay-per-check approach from Cloudflare's edge network.

## Known failure modes

- Host behind Cloudflare returns inconclusive result — Cloudflare's edge intercepts the connection
- Invalid or unresolvable hostname returns an error
- Timeout may cause filtered vs closed ambiguity
- Rate limiting or payment failure returns a 402 or error response

## How this service works

Is TCP port 25 (SMTP) open on a host? Attempts a connection from Cloudflare's edge and reports open/closed/filtered with the connect time; Cloudflare-fronted hosts are reported as inconclusive because their edge answers for them. Exposure checks for SMTP without running a scanner. $0.01 per check.

## Output

Returns whether TCP port 25 (SMTP) is open, closed, or filtered on the target host, along with the connection time in milliseconds. If the host is behind Cloudflare's edge network, the result is flagged as inconclusive because Cloudflare's infrastructure answers on behalf of the host.

## 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/is-port-25-open-d116db94/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)