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network-programmingsslprotocolstelnet

Is it possible to perform SSL handshaking via telnet?

I'm reading about how SSL works and tried to perform a handshaking with google pop3 server pop.gmail.com 995. I've found an example of the client hello message there. So, I connected to the gmail pop 3 server with

telnet pop.gmail.com 995

It's OK. Now I can send messages to the server. As far as I understand the first thing I need to do is to send is the client hello message. So I type the following line (I'll break lines after \r\n token for simplify reading):

ClientVersion 3,1\r\nClientRandom[32]\r\n
SessionID: None (new session)\r\n
Suggested Cipher Suites:\r\n
  TLS_RSA_WITH_3DES_EDE_CBC_SHA\r\n
  TLS_RSA_WITH_DES_CBC_SHA\r\n
Suggested Compression Algorithm: NONE

Press Enter and receive the message 

Connection closed by foreign host.

What's wrong? I was supposed to receive a server hello message? What do I send to receive that?

Solution

  • No, this is not possible. The text you're trying to type in is a human-readable representation of a ClientHello message, not the real thing. The real ClientHello message is binary data, and cannot be entered through a Telnet session.