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Open Port Scanner

TCP connect scan of the top 20 or top 100 ports of a host you own or are authorised to test.

RECON · SERVER-SIDE · RATE LIMIT 2/MIN
Only with the custom profile; each port must be in the top 100 list.

Only scan systems you own or are authorised to test. Each run is logged with your IP address.

Rate limited: one scan at a time, 2 per minute. Results are never stored. Too long to share as a link.

HISTORY

Your last 5 runs appear here for 7 days, on this device only.

RESULT

Fill in the form and run the tool; the result appears here.

Open Port Scanner runs a TCP connect scan against a host over a fixed list of ports (a top-20 or top-100 profile, or a custom pick from the top 100), reporting each port as open, closed or filtered with its likely service name. Only scan systems you own or are authorised to test.

How to read the result

The table lists state and service per port, open ports first: open accepted a connection, closed actively refused one, and filtered means no answer arrived within 1.5 seconds, usually a firewall silently dropping the packet. The service name is looked up from the port number alone; nothing is banner-grabbed or fingerprinted further.

The summary line shows the address scanned, the profile and the time taken. A run has 20 seconds; if a slow, filtered host uses that up, the ports not reached are left out and a note says how many.

Defender tips

  • Close anything you do not need reachable from outside; every open port is something that has to be patched, monitored and defended, forever.
  • Put administrative services (SSH, RDP, database ports, management interfaces) behind a VPN or bastion rather than exposing them directly, even with strong authentication in front of them.
  • Layer a host firewall on top of network controls; a single misconfigured network ACL should not be the only thing standing between an internal service and the internet.

FAQ

Why does a port show filtered instead of closed?

No response came back within the timeout at all. That is typically a firewall dropping the packet, whereas a closed port actively replies that nothing is listening there.

Why can custom ports only come from the top 100?

It bounds how long a single scan can run and how much load it puts on the target. For the same reason you can run one scan at a time, and a couple a minute.

Does it try to identify what is actually running on an open port?

No. It reports the port's conventional service name only; it never reads a banner or sends protocol-specific probes. Results are not stored; the run itself (time, your IP address and the host) is logged.

// RELATED FINDING Open administrative interfaces: impact, fix and references in the Findings Explorer