The following are the frequently used port numbers.

FTP data transfer mode – 20
FTP control(command) mode – 21
SSH – 22.
Telnet – 23..
WHOIS – 43.
DNS – 53

NNTP(Network news Transfer Protocol)-119

Web service port numbers
======================
http-80
Mysql-3306
https-443

Control panel default port numbers
============================
cPanel – 2082
secure cPanel – 2083
WHM -2086
secure WHM -2087
webmail – 2095
secure webmail – 2096
Plesk – 8443,8087
Webmin-10000

Mail port numbers
==============
IMAP-143
POP2-109
POP3-110
SMTP-25
IMAPS-993
SMTPS-465

Reference -en.wikipedia.org