Can the Telnet/Netcat client communicate over SSL?

Question

I would like to test client connections with IMAP over SSL, HTTPS, and other secure text-based Internet protocols over SSL/TLS, the same way I would using Telnet or Netcat if they were not tunneled over a secure protocol. Is there a way to get Telnet or Netcat to go through SSL/TLS such as with a pipe or alternate program?

Answer 1

First, there is no Telnet/Netcat client – they are two separate programs. Second, there is no "the" – there exist at least 10 different Telnet clients and at least 6 different Netcat versions.

• OpenSSL has a SSL client tool:

  openssl s_client -connect imap.gmail.com:993
  

  This is available for all operating systems. STARTTLS is supported via -starttls imap or -starttls smtp options.

• GnuTLS on Linux:

  gnutls-cli imap.gmail.com -p 993
  

  Use -s for STARTTLS.

• socat:

  socat openssl:imap.gmail.com:993 stdio
  

  readline mode can be used for convenience:

  socat ssl:imap.gmail.com:993 readline
  

  STARTTLS is not supported.

• ncat from nmap:

  ncat --ssl imap.gmail.com 993
  

• Some Telnet clients, such as the telnet-ssl package on Debian:

  telnet-ssl -z ssl imap.gmail.com 993