| Variable | Example | Description |
|---|---|---|
| ${HTTP_PORT} | 80 | The port used for http server |
| ${MYSQL_PORT} | 3306 | The port used for mysql database server |
| ${FTP_PORT} | 21 | The port used for ftp server |
| ${PASV_MIN_PORT} | 50000 | The minimum port used for passive ftp connections |
| ${PASV_MAX_PORT} | 50100 | The maximum port used for passive ftp connections |
| ${IMAP_PORT} | 143 | The port used for IMAP mail server |
| ${POP3_PORT} | 110 | The port used for POP3 mail server |
| ${SMTP_PORT} | 25 | The port used for SMTP mail server |