elstar.com.au

I found this site helpful with setting up sendmail to allow relaying via SMTP with authentication.

http://www.linuxquestions.org/linux/answers/Networking/Sendmail_SMTP_AUTH_Howto

to set up Certificate

cd /etc/pki/tls/certs

openssl req -new -x509 -keyout cakey.pem -out cacert.pem -days 1865

openssl req -nodes -new -x509 -keyout sendmail.pem -out sendmail.pem -days 1460

chmod 600 sendmail.pem

also this site was helpful
http://www.joreybump.com/code/howto/smtpauth.html