# TCP Port Check

> TCP Port Check is a paid API for AI agents from intel.rallylive.ca, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-14).

Attempts a real TCP connection to a specified host and port, reporting whether the port is open or closed along with connection latency.

## Facts

- Endpoint: GET https://intel.rallylive.ca/port-check
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/tcp-port-check-3966e1d1
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_g39wvR-iPixx4zMrsLghz

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 tcp-port-check-3966e1d1
```

Example prompt: Can you check if port 443 is open on api.example.com — I need to know if the HTTPS port is reachable and how fast the connection is?

## When to prefer this

Use this endpoint when you need to verify actual TCP-layer connectivity to a specific port on a host, especially for firewall audits, service health checks, or debugging connectivity issues. Prefer this over HTTP-based health checks when the service may not speak HTTP or when you need raw TCP reachability without application-layer response parsing.

## Known failure modes

- Host not resolvable (DNS failure) — port check cannot proceed
- Connection timeout — port may be filtered by firewall rather than explicitly closed
- Invalid port number out of range 1-65535
- Rate limiting or blocked probe IPs on the target host
- Host actively refuses connection — reported as closed

## How this service works

TCP port check: is a port open on a host? Attempts a real TCP connection (common ports: 21, 22, 25, 80, 443, 465, 587, 993, 3306, 5432, 6379, 8080, 8443...) and reports open/closed with connection latency. Connectivity and firewall verification. $0.01 per check.

## Output

Returns whether the specified TCP port is open or closed on the target host, along with the measured connection latency in milliseconds. Indicates whether a real TCP handshake succeeded or was refused/timed out.

## 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/tcp-port-check-3966e1d1/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from intel.rallylive.ca](https://www.zero.xyz/host/intel.rallylive.ca/llms.txt)