Mailing List Message #106408
From: Nicolas Hatier <>
Subject: Re: SMTP and TLS 1.2
Date: Fri, 12 May 2017 18:40:59 -0400
To: CommuniGate Pro Discussions <>

This is for the oldest accepted protocol when accepting a connection from the outside.

When CGP initiates an SMTP connection to a smart host, it uses TLS 1.0 by default as Ralf Zenklusen explained.

Using the --SMTPOutgoingTLSVersion 3 startup option worked perfectly.

Nicolas Hatier, ing. <>
Niversoft idées logicielles -

On 2017-05-12 03:38, Brian Turnbow wrote:

Communigate has tls 1.2 from 6.1 ,  so if the server is up to date you 
should be ok.
You can set the “oldest accepted” to tls 1.2  in the general  → other  to 
force tls 1.2.
Be aware that this may break connections to other mail server that are not 
configured to support 1.2...
As it is a global setting.


From: CommuniGate Pro Discussions [] On 
Behalf Of Nicolas Hatier
Sent: giovedì 11 maggio 2017 18:59
To: CommuniGate Pro Discussions
Subject: SMTP and TLS 1.2


Can CGP send using TLS 1.2 when forwarding mail to a smarthost? (SMTP / 
Sending , Forward to...)

My client's ISP tells me TLS 1.2 is enabled on their server and they are 
going to retire 1.0 within a few months.
Send Encrypted (at the bottom of the same page) is configured properly.

However, in the logs, the TLS version used always seems to be 1.0:

12:32:03.191 2 TLS-000006 created(TLSv1.0,ECDHE_AES256_SHA) -> [x.x.x.x]:587 
for SMTP-000007
12:32:03.277 4 SMTP-000007(*) TLS-000006 secure(ECDHE_AES256_SHA) connection 

I don't know enough about TLS to be sure whether or not the issue is on CGP 
side or on the ISP side.


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