Postfix with SMTP-auth

main.cf

smtpd_recipient_restrictions =
...
   permit_sasl_authenticated
...

smtp_use_tls = yes
smtpd_tls_auth_only = no

tls_random_source = dev:/dev/urandom
tls_daemon_random_source = $tls_random_source

# How to make SSL key

smtpd_tls_cert_file = /etc/ssl/certs/cert.pem
smtpd_tls_key_file = /etc/ssl/certs/cert.key
smtpd_use_tls = yes

smtpd_sasl_auth_enable = yes
smtpd_sasl_security_options = noanonymous
smtp_sasl_security_options = noanonymous
smtpd_sasl_local_domain =