Port Checker

A port check tests whether a specific TCP port on a remote host is accepting connections. Each networked service (web server, database, SSH) listens on a designated port number.

This tool attempts a TCP connection to the target port and reports whether the connection was accepted (open), refused (closed), or timed out (filtered by a firewall).

• Use Single Port to test one specific TCP port on a host.
• Use Port Range to scan up to 100 consecutive ports at once.
• Use Common Ports for a quick scan of 20 well-known service ports (FTP, SSH, HTTP, HTTPS, MySQL, RDP, etc.).
• Adjust the timeout for slow or distant hosts. Higher values reduce false "filtered" results but increase scan time.
• The dice loads a random example: scanme.nmap.org, whose owner invites scans, or a public service on its usual port.

• This tool checks TCP ports only. UDP port scanning requires different methods and is not supported here.
• Only scan hosts you own or have explicit permission to test. Unauthorized port scanning may violate network policies.
• Large port ranges (up to 100 ports) are scanned sequentially and may take considerable time depending on the timeout setting.
• A filtered result does not always mean a firewall is blocking the port. Network congestion or routing issues can also cause timeouts.