# is-port-23-open

> is-port-23-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 2026-10-10).

Checks whether TCP port 23 (Telnet) 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/23?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-10
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/is-port-23-open-27f3c7d1
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_NOfOGdirk5nGm6TLRkudU

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-23-open-27f3c7d1
```

Example prompt: Can you check if TCP port 23 (Telnet) is open on host 192.168.1.100? I want to know if it's exposed without running a full scanner.

## When to prefer this

Choose this endpoint when you need a quick, external Telnet (port 23) exposure check on a host without deploying your own network scanner. It's ideal for security audits, compliance checks, and asset monitoring where you need an outside-in perspective on port 23 specifically. Note the Cloudflare-fronted host limitation — if you know the target is behind Cloudflare, results will be inconclusive.

## Known failure modes

- Invalid or unresolvable hostname returns an error
- Cloudflare-fronted hosts return inconclusive result rather than true port status
- Network timeouts may cause filtered vs closed ambiguity
- Private/RFC1918 IP addresses may not be reachable from Cloudflare's edge
- Rate limits or payment failures return 402 or error response

## How this service works

Is TCP port 23 (Telnet) 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 Telnet without running a scanner. $0.01 per check.

## Output

Returns the port status as open, closed, or filtered, along with the connection attempt time in milliseconds. If the host is fronted by Cloudflare's edge network, the result is marked as inconclusive since Cloudflare answers on behalf of the origin.

## 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-23-open-27f3c7d1/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)