How to force JavaMailSenderImpl to use TLS1.2?

问题

Have a JDK7 app running on Tomcat and it does have the following env settings:

-Dhttps.protocols=TLSv1.1,TLSv1.2 

The above setting ensures that we don't use TLS 1.0 when connecting over HTTPS while making API calls etc.

We also use the org.springframework.mail.javamail.JavaMailSenderImpl class to send outgoing SMTP email, and use these props:

 mail.smtp.auth=false;mail.smtp.socketFactory.port=2525;mail.smtp.socketFactory.fallback=true;mail.smtp.starttls.enable=true

The problem is that the connection to the SMTP email server is failing when it's upgraded to TLS1.2.

javax.net.ssl.SSLHandshakeException: Remote host closed connection during handshake

Is there a settings or code change that will force the TLS1.2 protocol?

I did some searching and it looks like these env settings are only for applet and web clients, not for server side apps

-Ddeployment.security.SSLv2Hello=false -Ddeployment.security.SSLv3=false -Ddeployment.security.TLSv1=false

回答1:

This is the fix for the next guy looking:

mail.smtp.starttls.enable=true; mail.smtp.ssl.protocols=TLSv1.2;

来源：https://stackoverflow.com/questions/47166425/how-to-force-javamailsenderimpl-to-use-tls1-2