Port Scanner — Check Open Ports Online

Domain or IP

Share X / Twitter Facebook LinkedIn WhatsApp

How to use Port Scanner

Enter a host you own or are authorized to test — never someone else's without permission.
Review the open ports — each maps to a running, internet-exposed service.
Flag what shouldn't be public: databases (3306/5432), admin panels, dev servers.
Remediate and re-scan: firewall, restrict binding to localhost, or close — then confirm.

What is Port Scanner?

A port scanner checks which network ports on a host are open — accepting connections — revealing the services running there: port 80/443 (web), 22 (SSH), 25/587 (mail), 3306 (MySQL), and so on. Open ports are doors; the scan inventories which are unlocked.

The responsible-use framing is non-negotiable: port scanning is a legitimate, essential security-audit technique on your OWN systems (and authorized ones) — and unauthorized scanning of others' hosts is at best rude and in many jurisdictions illegal. Scan what you own or have written permission to test. Full stop.

About the Port Scanner

Enter a host you own or are authorized to test, and see which common ports respond as open.

The legitimate audit uses: your own attack-surface check — the core one: every open port is a service exposed to the internet, and the goal is that ONLY the ports you intend (443 for web, maybe 22 for SSH) are open, with databases (3306, 5432), admin panels and dev services firewalled off; firewall verification — confirming your rules actually closed what you meant to close (the gap between "configured" and "effective" is where breaches live); finding forgotten services — that old service listening on an odd port nobody remembers starting; and post-hardening confirmation — re-scanning to prove a lockdown worked.

Reading results: an open database or admin port facing the public internet is a serious finding — such services should bind to localhost or sit behind a VPN/firewall, never open to the world. This is discovery, not exploitation; findings feed remediation (close the port, firewall it, restrict the binding), not intrusion. Pair with HTTP Headers and SSL checks for the services that should be open.

Frequently Asked Questions

On your own systems, entirely. On others', it ranges from unwelcome to criminal depending on jurisdiction and intent — many places treat unauthorized scanning as an offense. Rule: scan only what you own or have explicit written permission to test.

Ideally just 443 (HTTPS), plus 80 (HTTP, to redirect to HTTPS) and possibly 22 (SSH, ideally IP-restricted). Everything else — databases, admin, dev — should be firewalled off from the public internet.

Serious — a publicly reachable database is a prime target for brute-force and exploitation. Fix immediately: bind it to localhost, firewall it to known IPs, or put it behind a VPN. It should never accept connections from the open internet.

Open = a service is listening and accepting. Closed = reachable host, nothing listening there. Filtered = a firewall is dropping the probe (no answer either way). Filtered is often the desired state for ports you don't expose.

It means that door is shut — necessary, not sufficient. Security also depends on the open services being patched and configured well, strong authentication, and the rest of the stack. Port hygiene is one layer of many.