Hi Michal,

Thanks for making that a lot clearer!

You remind me of my college days (and nights!) when referring to finite state machines - I have a very good working knowledge of these as well! ;)

That's very good news... so I presume the line:

2014.10.28 14:35??:55 LOG6[4156]: Negotiated TLSv1 ciphersuite ECDHE-RSA-AES256-SHA (256-bit encryption)

... is the confirmation that the TLS protocol is being used?

(Apologies for my delayed response - I was out of the office yesterday.)

Regards, Stephen

________________________________________ From: stunnel-users [email protected] on behalf of Michal Trojnara [email protected] Sent: 29 October 2014 16:14 To: [email protected] Subject: Re: [stunnel-users] Exchange Online - SSLv3 and Sophos UTM 120 firewall update

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Stephen Hogan wrote:

2014.10.28 14:35:55 LOG7[4156]: SSL state (connect): SSLv3 write client hello A

[cut]

I have a basic (shaky) understanding that the "handshake" for TLS does downgrade to SSLv3 if newer versions of TLS fail, but I am wondering if I apply the update recommended on the firewall, will this cut the communication for the SMTP relay, the way I am using it?

The debug messages produced by stunnel can sometimes be confusing. They are intended to be helpful to developers, and not end-users.

OpenSSL implements the SSL/TLS/DTLS protocols with three separate finite state machines: SSLv2, SSLv3, and DTLS1. http://en.wikipedia.org/wiki/Automata-based_programming All TLS protocols use the SSLv3 state machine, thus the state name does not reflect the actual protocol being negotiated.

See the source for details: https://github.com/openssl/openssl/blob/master/ssl/ssl_stat.c

Best regards, Mike

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