NET Framework 3.5Ĭumulative Update for Windows 10 Version 1511 and Windows Server 2016 Technical Preview 4: May 10, 2016 To test a web server or some other service that does not require a command to negotiate SSL/TLS, omit the -starttls option.Minimum update needed to support TLS 1.2 with. If the SSL/TLS version is not supported, it looks like this instead. New, TLSv1/SSLv3, Cipher is DHE-RSA-AES256-SHA If the SSL/TLS version is supported, openssl prints a section like this near the end of the output. Openssl s_client -connect localhost:25 -starttls smtp -tls1_2 < /dev/null

For example, to test the local sendmail server to see whether it supports TLS 1.2, use the following command. To test such a service, use the -starttls option of s_client to tell it which application protocol to use. There is a man page for the subcommand ( man s_client) which lists its options.Ĭertain application protocols, such as FTP or SMTP, require that the client requests TLS support before a secure connection can be negotiated. They have the same names but preceded with 'no_' for example, -no_ssl2. There are also options to prevent the use of a particular protocol version (or versions) during negotiation.

The -ssl2, -ssl3, -tls1, -tls1_1, and -tls1_2 options force s_client to use SSLv2, SSLv3, TLSv1.0, TLSv1.1, or TLS1.2. You can tell s_client which protocol to use or which not to use. This subcommand pretends to be a client program and shows you the results of its SSL/TLS negotiation with the server. To test whether or not a service on a particular port supports TLS 1.1 or 1.2 (or prevents the use of versions such as SSL 3), use the openssl command with the subcommand s_client.

Test tls 1.2 support