Http, FTP SMTP Port Testing using Telnet

- Online Port Testing :  http://ping.eu/
- Free port ping utility
Cross-platform TCP port testing
Command Line Port Scanner

HTTP Port Testing using Telnet
telnet www.somesite 80
GET /index.html HTTP/1.1
Host: www.somesite.com
(Note: you need to press enter twice at the end)
SMTP Port Testing using Telnet
telnet myserver.domain.25
helo myserver.domain.com
mail from:
rcpt to:
data
subject: This is a test mail
to: recipientname@mydomain.com
This is the text of my test mail.
.
quit
    .
FTP Port Testing using Telnet
telnet ftp.ietf.org 21
USER anonymous
PASS blogger@webdigi.co.uk
CWD
PASV
RETR ftpext-test.txt
QUIT