/etc/pki certificate questions

[Daniel B. Thurman]

I wondered where I can find fedora information regarding
the cert files placed in: /etc/pki directory.

Apparently, there is tls/certs/localhost.pem and tls/private/localhost.key;
are these two files required?

I also noticed that installing certain servers such as sendmail, spamd,
imap, ... creates the pem/crl/key certs, but they contain default (otherwise
incorrect [example.com]) certificate information?

As for sendmail, I cd'd into the certs directory, issued: make sendmail.pem
and enabled the SSL in sendmail.mc file, but apparently, I can no longer
log into sendmail (Thunderbird keeps requesting the password) in order
to send outgoing email messages, so I am wondering if "localhost" is
involved somehow?

I would like to rebuild these [self-signed] certificates so that they 
contain
correct servers certificates, notably dovecot, sendmail, spamd,
.... and lastly "localhost", if this is required?

Does anyone recommend a very good site for dealing with the
above issues?

Kind regards,
Dan