Ecco alcuni articoli utili sul telnet:
XFOR: Telnet to Port 25 to Test SMTP Communication
http://support.microsoft.com/default.aspx?scid=kb;en-us;153119
XFOR: Verifying Basic POP3 Connectivity Using Telnet
http://support.microsoft.com/default.aspx?scid=kb;en-us;165186
How to verify basic IMAP connectivity by using Telnet
http://support.microsoft.com/default.aspx?scid=kb;en-us;189326
The TELNET Protocol
http://support.microsoft.com/default.aspx?scid=kb;en-us;231866
Se poi si devono fare varie prove diventa veramente utile farsi un script con WSH di seguito ne riporto uno per inviare una mail, ma ovviamente lo si può adattare a qualunque esigenza come ad esempio eseguire in modo automatico qualche attività su un router o altri dispositivi configurabili via telnet.
Set oShell = WScript.CreateObject("WScript.Shell")
oShell.Run "Telnet IpServer 25"
WScript.Sleep 500
oShell.SendKeys "helo test.com{ENTER}"
WScript.Sleep 500
oShell.SendKeys "MAIL FROM:me@test.com{ENTER}"
WScript.Sleep 500
oShell.SendKeys "RCPT TO: user@domain.cn{ENTER}"
WScript.Sleep 500
oShell.SendKeys "DATA{ENTER}"
WScript.Sleep 500
oShell.SendKeys "Subject: test message{ENTER}{ENTER}"
WScript.Sleep 500
oShell.SendKeys "This is a test message you will not see a response from this command.{ENTER}"
WScript.Sleep 500
oShell.SendKeys ".{ENTER}"
WScript.Sleep 500
oShell.SendKeys "QUIT{ENTER}"
Per maggiori info su SendKeys si veda:
http://msdn.microsoft.com/library/en-us/script56/html/4b032417-ebda-4d30-88a4-2b56c24affdd.asp