myhostname = mail.domain1.jp
mydomain = domain1.jp

relayhost = [smtp.gmail.com]:587

# Gmail relay
smtp_sasl_auth_enable = yes
smtp_sasl_mechanism_filter = plain
smtp_sasl_password_maps = hash:/etc/postfix/gmail
smtp_sasl_security_options = noanonymous
smtp_sasl_tls_security_options = noanonymous
smtp_tls_CAfile = /etc/ssl/certs/ca-certificates.crt
smtp_tls_security_level = encrypt
smtp_use_tls = yes