格 千格 KiloCell

Online Port Scanner

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Note: Owing to the security restrictions on browser sandboxes, a purely front-end web page cannot be used to perform real TCP/UDPs directly on external servers Port scan. This tool is only for use Simulation Presentation Common ports and their corresponding services. If you need to do a real scan, use such specialized tools as Nmap locally.

Depth resolution: port scan and network security

In network communications, Port is the logical interface between the application layer service and the transfer layer protocol. If the IP is put The address is a reference to the address of the building, so the port is the door to the different rooms. Port scanning is the first step in a network security audit to detect services that are open on the target mainframe.

Common ports and their corresponding services

  • 80 (HTTP) & 443 (HTTPS)： Standard port for web services. The port provides encrypted transmission through SSL/TLS.
  • 22 (SSH)： Safety shell protocol for remote login and management of Linux servers.
  • 21 (FTP)： The file transfer protocol, although old, is still widely used in certain scenarios.
  • 3306 (MySQL) & 5432 (PostgreSQL)： Common database service port.
  • 6379 (Redis)： High performance memory databases, often used for caches.

Why is port scanning essential for safety?

Exposure analysis: Open ports mean open services. Each open service may have a loophole. Through port scanning, administrators can confirm whether unnecessary services are being exposed to the public web (e.g., database ports), thereby reducing exposure to attack by closing them in a timely manner.

Service fingerprint recognition: Professional scanning tools (e.g., Nmap identifies not only the open port but also the specific service version. If running is the existence of known CVE The old version of the gap must be upgraded by the administrator immediately.

How do you do a real port scan?

For professional penetration testing or system maintenance, use of command line tools is recommended Nmap 。 For example, running nmap -sV example.com You can scan the most common 1000 A port and an attempt to identify the service version. Please note that unauthorized scanning of someone ' s servers is illegal in many countries and territories and must be used in compliance conditions.