Programma per connettersi ad un determinato Host. Usato ad esempio per connettersi via LAN ad un router per configurarlo (sempre che questi ammetta la configurazione via telnet). Occorre conoscere l'indirizzo IP del dispositivo a cui ci si desidera connettere.
Via telenet e' anche possibile configurare gli adattatori di rete delle stampanti (HP jetdirect ad esempio)

SMTP: invio messaggio di email da telnet

B:\>telnet blat.tld 25

220 miniRelay Server v0.9.75 ready
HELO blat.tld
250 Hello blat.tld
mail from: <tim@blat.tld>
250 tim@blat.tld Address Okay
rcpt to:<tim@blat.tld>
250 tim@blat.tld Address Okay
354 Start mail input; end with <CRLF>.<CRLF>
subject:The text you want on the subject line

This is the message body!
250 Ok
221 Signing Off

SMTP con autenticazione

B:\>telnet blat.tld 25

220 miniRelay Server v0.9.75 ready
HELO blat.tld
250 Hello blat.tld

334 VXNlcm5hbWU6  (in BASE64 Utente:)
(inserire qui l'utente codificato in BASE64)    .... vedi  per conversione in BASE64
334 UGFzc3dvcmQ6 (in BASE84  Password:)
(inserire qui  la password codificata in BASE64)
235 2.0.0 OK Authenticated
....poi prosegue normalmente

POP3: lettura posta via telnet

Consultazione casella POP3 via telnet

telnet host pop3  
telnet host 110

USER userid

This must be the first command after the connect. Supply your e-mail userid (not the full e-mail address). Example: USER john.smith

PASS password

This must be the next command after USER. Supply your e-mail password. The password may be case sensitive.
The following commands may be used as needed:


The response to this is: +OK #msgs #bytes Where #msgs is the number of messages in the mail box and #bytes is the total bytes used by all messages. Sample response: +OK 3 345910


The response to this lists a line for each message with its number and size in bytes, ending with a period on a line by itself. Sample response:

+OK 3 messages
1 1205
2 305
3 344400

RETR msg#

This sends message number msg# to you (displays on the Telnet screen). You probably don't want to do this in Telnet (unless you have turned on Telnet logging). Example: RETR 2

TOP msg# #lines

This is an optional POP3 command. Not all POP3 servers support it. It lists the header for msg# and the first #lines of the message text. For example, TOP 1 0 would list just the headers for message 1, where as TOP 1 5 would list the headers and first 5 lines of the message text.

DELE msg#

This marks message number msg# for deletion from the server. This is the way to get rid a problem causing message. It is not actually deleted until the QUIT command is issued. If you lose the connection to the mail server before issuing the QUIT command, the server should not delete any messages. Example: DELE 3


This resets (unmarks) any messages previously marked for deletion in this session so that the QUIT command will not delete them.


This deletes any messages marked for deletion, and then logs you off of the mail server. This is the last command to use. This does not disconnect you from the server, just the mailbox.