It's always handy to know what port numbers each of the common TCP services use. Whether it's for setting up port forwarding (nat) or providing access past a firewall, here is a handy list of ports we frequently find ourselves looking up.
DNS - 53
FTP - 21
HTTP - 80
HTTP (SSL) - 443
iMail5 - 46245
iMail5 (SSL) - 46246
IMAP4 - 143
IMAP4 (SSL) - 993
LDAP - 389
LDAP (SSL) - 636
NNTP - 119
NNTP (SSL) - 563
POP3 - 110
POP3 (SSL) - 995
SMTP - 25
SMTP (SSL) - 465
TELNET - 23
SSH - 22