relayhost=[smtp.fh-schmalkalden.de]:submission 

smtp_tls_security_level = encrypt
smtp_tls_CApath = /etc/postfix/certs

smtp_sasl_auth_enable = yes
smtp_sasl_security_options = noanonymous
smtp_sasl_password_maps = hash:/etc/postfix/sasl_password

sender_canonical_maps = hash:/etc/postfix/sender_canonical