I have a FreeBSD 7.0 server where I'd like to authenticate against
/etc/master.passwd when using SMTP AUTH and Sendmail. This means
using LOGIN, which can use either plain text or SSL-tunneled
connections. I'd like to allow SMTP AUTH only over SSL, and disallow
it over unencrypted connections. Any suggestions on this? Surely
there's just some switch I'm missing? The archives and search engines
are full of people trying to get SSL working, not people trying to
turn off non-SSL connections.
Here's the relevant snippets of sendmail.mc I'm using.