Important Port Numbers

15                Netstat

21                FTP

23               Telnet

25                SMTP

110              POP3

42                WINS

53                DNS

67                Bootp

68                DHCP

3268            AD Global Catalog

3269            AD Global Catalog over SSL

88                Kerberos

101              HOSTNAME

139              NetBIOS

161              SNMP

180              RIS

389              LDAP (Lightweight Directory Access Protocol)

80                HTTP

443              HTTPS (HTTP over SSL/TLS)

443              SSL (https) (http protocol over TLS/SSL)

220              IMAP3

119              NNTP

123              NTP     (Network time protocol)