Port Scan

This tool can scan common ports and whether the specified ports are open.

Common port numbers:

Proxy server commonly used ports:
(1). HTTP protocol proxy server commonly used port number: 80/8080/3128/8081/9080
(2). SOCKS proxy protocol server commonly used port number: 1080
(3). FTP (file transfer) protocol proxy server commonly used port number: 21
(4). Telnet (remote login) protocol proxy server commonly used port: 23