It need to add next package to postfix server:
yum install cyrus-sasl cyrus-sasl-lib cyrus-sasl-plain
and add the next rows to postfix main.cf file:
smtp_sasl_auth_enable = yes
smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
smtp_sasl_security_options = noanonymous
smtpd_sasl_path = smtpd
relayhost = [smtp.server.name]
smtp_generic_maps = hash:/etc/postfix/generic
Aslo need add to file /etc/postfix/sasl_passwd auth data in the next format:
smtp.server.name username:password
then run
postmap /etc/postfix/sasl_passwd
Due to local mail send from root user, you need to change mailer from (it is if your exchange server doesn't allow anonymous connection). Add to file /etc/postfix/generic row:
root@your_linux_server_name username
and run
postmap /etc/postfix/generic
and restart postfix
