Do my hosted mailboxes use any type of TLS when sending email?
Outbound Service Mail, Mailboxes
With regards to email, TLS is a standards-based protocol based on Secure Socket Layer (SSL). TLS is rapidly being adopted as the standard for secure email. The protocol uses cryptography to provide endpoint authentication and communications privacy over the Internet. TLS is IP based, which means that all mailboxes using the Oracle's shared IP ranges will be affected as follows.
Service emails are sent with opportunistic TLS, this includes both hosted and non-hosted mailboxes that do not send from a dedicated IP. With opportunistic TLS anytime we make a connection with an ISP we are checking whether they support TLS, if they do we send TLS. If the ISP does not support it, we will send the message over a basic SSL communication string.
TLS provides a secure encryption of the transfer from our mailbox/MTA's to the recipient's mailbox/MTA's, essentially outsiders can't look in. In addition, note that reputation can still be applied when using TLS and mailbox SSL settings are separate from TLS encryption.