TLS configuration - email client Vs. email server


Oct 10, 2022
cPanel Access Level
Website Owner

My current email server (Exim from cPanel/WHM) has TLS authentication enabled, so when I use webmail I'm sure my emails will be sent over with this authentication method if the destination server also uses it.
My question arises when I use an email client for that, for example, if Thunderbird doesn't have TLS authentication enabled it means that the emails sent wouldn't be authenticated using this method, even the destination email server having this security option already enabled?

I'm trying to understand if when activating or deactivating TLS in Thunderbird it would be considered only for the communication with my mail server or if that configuration would also be valid for the final destination point, e.i., the recipient's mail server.
If the default behavior is the last one then I assume that the security settings of the email client, in this case Thunderbird, would override the settings of my own mail server (Exim).