Raymond Norton said:
> Can you telnet to port 25 of the server?

I sure could. That was of no help. I looked at the sendmail.cf diff, but
that was pretty cryptic.

So I checked the logs... finally checking /var/log/maillog. There was a
warning about STARTTLS that it couldn't find the ca-bundle, which is the
root certificate authority bundle. STARTTLS failed, meaning I could not
initiate a secure connection, and unsecure connections are refused.

Apparently FC4 has moved the ca-bundle to
/usr/share/apps/kssl/ca-bundle.crt and/or
/etc/pki/tls/certs/ca-bundle.crt.

It took a simple change to sendmail.mc to point to the first one, and now
SMTP with a STARTTLS encryption wrapper works once again.

Thanks for the tries, fellas.