Importent Port Numbers

Well known port numbers

 21     FTP -- Control
 22     SSH Remote Login Protocol
 23     Telnet
 25     Simple Mail Transfer Protocol (SMTP)
 53     Domain Name System (DNS)
 67        DHCP Clint
 68        DHCP SERVER
 80     HTTP
110     POP3
143     Interim Mail Access Protocol (IMAP)
389     Lightweight Directory Access Protocol (LDAP)
443     HTTPS
546     DHCP Client
547     DHCP Server