No TLS; connection is unencrypted and attempts to upgrade with STARTTLS will be rejected.
No TLS; connection is unencrypted and attempts to upgrade with STARTTLS will be rejected. This is provided for testing and for compatibility with the old manager.
Initial connection uses TLS.
Default STARTTLS behavior.
Default STARTTLS behavior. Connection starts unencrypted and we use STARTTLS to upgrade later. STARTTLS is required for remote connections, but optional for connections from localhost.
STARTTLS is required for all connection, including from localhost.
STARTTLS is optional for all connections, including from remote hosts.