Internet Technologies/Telnet

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Telnet is a protocol designed to remotely access computers in a client-server fashion. Telnet is inherently insecure, as the data passed from the client to the server or vice-versa is not encrypted. For connections through insecure networks (such as the Internet), SSH (Secured SHell), should be used so all communications between the client and server are encrypted.

Examples[edit | edit source]

Test if the HTTP port is open and its service listening[edit | edit source]

telnet localhost 80

Send an email[edit | edit source]

telnet localhost 25
Connected to localhost.localdomain.
Escape character is '^]'.
mail from:<>
250 2.1.0 <>... Sender ok
rcpt to:<>
250 2.1.5 <>... Recipient ok
354 Enter mail, end with "." on a line by itself
Let's meet
250 2.0.0 n514OvkN019941 Message accepted for delivery
221 2.0.0 closing connection
Connection closed by foreign host.