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Port Checker — Check Open Ports

Enter an IP or domain and a port to find out whether it accepts TCP connections from the internet. Ideal for validating port forwarding, firewalls and game servers.

Target

The connection is made from a Cloudflare server, not from your browser. Only the host and port are sent; nothing is stored.

Common ports

Use via API

Tests whether a TCP port accepts connections on a public IPv4 or domain.

POSThttps://enhanced.dev.br/api/v1/network/port-check
JSON body parameters
Body (JSON)TypeDescription
host *stringPublic IPv4 or domain.
port *1–65535TCP port (25 is blocked).

Request example

curl -X POST "https://enhanced.dev.br/api/v1/network/port-check" \
    -H "Content-Type: application/json" \
    -d '{"host":"8.8.8.8","port":53}'

Response

{
  "ok": true,
  "data": {
    "host": "8.8.8.8",
    "port": 53,
    "status": "open",
    "latencyMs": 32
  },
  "meta": {
    "version": "v1"
  }
}
  • Errors return { ok: false, error: { code, message } } with an HTTP 4xx/5xx status.
  • Free, no API key required. Limited to 20 requests per minute per IP.
  • For security, browsers may only call this endpoint from this site; call it from a back end (Node, Python, cURL).
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How to use

  1. Type the server's public IP or domain.
  2. Pick a common port from the list or type any port, such as 30120.
  3. Click Check and wait up to 5 seconds.
  4. Read the result: open, closed or no response.

Use cases

  • Confirming that router port forwarding works.
  • Checking whether a FiveM (30120), Minecraft (25565) or TeamSpeak server is reachable for players.
  • Validating firewall rules and security groups after a deploy.
  • Making sure sensitive services such as RDP (3389) or MySQL (3306) are not exposed unnecessarily.

Technical concepts

Open, closed and filtered

An open port completes the TCP handshake (SYN, SYN-ACK, ACK). A closed port replies immediately with RST, refusing the connection. A filtered port does not reply at all: a firewall silently drops the packets and the test times out.

Why the test runs on a server

Browsers cannot open arbitrary TCP connections and block several ports for security. That is why this tool, unlike the others on the site, sends the host and port to a function on Cloudflare's edge, which attempts the connection and returns the result. Nothing is stored.

Port forwarding and CGNAT

To expose a service on a home network, the router must forward the external port to the machine's internal IP. If your ISP uses CGNAT (IPs in 100.64.0.0/10), forwarding will not work without a dedicated public IP, a VPN or a tunnel.

TCP only

The test checks TCP ports. UDP-only services, like part of game and VoIP traffic, cannot be confirmed with a TCP connection; a closed result does not mean the UDP service is unreachable.

Frequently asked questions

Can I check an IP on my local network, like 192.168.0.10?

No. Private addresses are not reachable from the internet. Enter your connection's public IP or a domain that points to it.

Why does the port show as closed when the server is running?

The most common causes are the operating system firewall, missing port forwarding on the router, a service listening only on 127.0.0.1 or ISP CGNAT.

Why can't port 25 be tested?

Cloudflare's infrastructure blocks outbound connections on port 25 (SMTP) to prevent spam.

Is there a check limit?

Yes. To prevent abuse such as port scanning, each visitor can run up to 20 checks per minute, one port at a time.

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