Tools

Port Checker

Port

Popular ports

PortDescribe
21FTP - File Transfer Protocol
22SSH, SFTP - Secure SHell and SSH based FTP
23Telnet - non-secure shell
25SMTP (Simple Mail Transfer Protocol) - sending and receiving email messages
53DNS (Domain Name System) - mapping from hostname to ip and vice versa
80HTTP (HyperText Transfer Protocol) - main protocol of world wide web
110POP (Post Office Protocol) - mail retrieval protocol
143IMAP (Internet Message Access Protocol) - mail retrieval protocol
443HTTPS - secure HTTP
3306MySQL database
3389RDP - Remote Desktop