"Enable authentication for outgoing mail" in Thund

[gothor]

I configured Thunderbird according to the Mozilla Mail instructions. Everything seems okay, I can send and recieve mail. But I can't quite figure out how to "enable authentication for outgoing mail" in Thunderbird, or even if its necessary.

Thunderbird gives me the following options under outgoing/SMTP Server:

Use Secure Connection: No, TLS (If available), TLS or SSL.

Right now I have TLS, If Available set.

Is that right?