Softonic

TCP Port Checker

Step 1 / 2

Only run port checks on hosts you own or have permission to probe.

Next

Enter a public hostname or IP address and one port from 1 to 65535. Our server makes a TCP connection attempt with a five-second timeout. “Open” means that connection was accepted from our server; every failed attempt is shown as “Closed”, with the system error underneath when available.

What the check does

  1. 1

    Validate the target

    The tool resolves DNS and rejects private, loopback, link-local, documentation and other non-public addresses.

  2. 2

    Attempt one TCP connection

    The application server calls a normal TCP connect for the selected port and waits up to five seconds.

  3. 3

    Interpret carefully

    Accepted is Open. Refusal, timeout, routing failure and other connection errors all use the Closed label; the tool cannot reliably separate them.

What the result means

Display What was observed What it does not prove
Open A TCP connection from this service was accepted The named service is genuine, secure or working correctly
Closed The TCP connection did not open Whether it was refused, filtered, timed out or failed elsewhere

The “Service” name is only a lookup based on the entered port number. No banner is read and no protocol or version is fingerprinted. Response time is elapsed time for the attempt, not network latency alone.

Common TCP port-number associations

Port Label shown or common association
22 SSH
25 SMTP
53 DNS (TCP is tested, not UDP)
80 / 443 HTTP / HTTPS
3306 / 5432 MySQL / PostgreSQL
6379 / 27017 Redis / MongoDB

Port assignments describe conventional uses, not what is actually running. Check only systems you own or have permission to test.

Scope and privacy

This is a server-side TCP connect, not a scan from your browser or home network. It cannot test localhost, router-only or private-LAN addresses, UDP, port forwarding from inside your LAN, service versions, firewall rules or stealth. The host and port are server fields; the step-by-step flow also places them in the URL. Executions are logged with the target host and port, so do not treat a query as secret.

Frequently Asked Questions

Not necessarily. The same label covers refusal, timeout and other failures. A firewall, routing problem or temporary service issue can produce it.

No. It performs only a TCP connection attempt.

No. Private and other non-public targets are blocked, and the connection originates from our server on the public internet.

Access can vary by source address, network route and firewall policy. Open only proves our server connected at that moment.

The application logs an execution with the host and port. In funnel mode they also appear in the URL. Do not submit sensitive target information.

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Tool available in other languages