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