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I was executing the command

openssl s_client -connect x.x.x.x:443 -status -debug

I can see that the Server is sending it's SSL cert but in the command prompt I'm getting at the end :

SSL3 alert read:warning:close notify SSL3 alert write:warning:close notify

Is this an error message? What would it mean ?

Thank you

1 Answer 1

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Is this an error message?

No, its not.

What would it mean ?

close_notify alert is the normal way to stop a TLS session which should be done before closing the underlying TCP connection. See also RFC 5246 7.2.1 Closure Alerts.

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  • Thank you @Steffen Ullrich. Just oconfirm, but that would prove that we are able to establish first a 3-way handshake and a secure SSL/TLS channel ? Am I correct?
    – cyzczy
    Aug 11, 2016 at 9:40
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    @adam86: I would read the RFC in a way that these alerts are only used to close an successfully established session but I would not count on it that some stack will send these alerts are also when closing a not yet fully established session. To check for a successful session look for the server finished message and if the parties exchange data after that. Aug 11, 2016 at 10:13
  • @SteffenUlIrich I see your point. I started Wireshark in the same time while running the openSSL query and I could see the TCP-connection being established and next the TLS-handshake taking place, so it proves that your answer was correct. Thank you again. I highly appreciate your expertise.
    – cyzczy
    Aug 11, 2016 at 13:10

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