List of important port number

15  Netstat 21  FTP 23  Telnet 25  SMTP 42  WINS 53  DNS 67  Bootp 68  DHCP 80  HTTP 88  Kerberos 101  HOSTNAME 110  POP3 119  NNTP 123  NTP(Network time protocol) 139  NetBIOS 161  SNMP 180  RIS 389  LDAP(Lightweight Directory Access Protocol) 443  HTTPS (HTTP over SSL/TLS) 520  RIP 79  FINGER 37  Time 3389 Terminal services 443  SSL (https) (http protocol over TLS/SSL) 220  IMAP3 3268 AD Global Catalog 3269 AD Global Catalog over SSL 500  Internet Key Exchange, IKE (IPSec) (UDP 500)