[root@localhost Server]# vim /etc/postfix/main.cf
Just see 107 no: line here
[root@localhost Server]# postconf -e inet_interfaces=all
[root@localhost Server]# alternatives - - set mta /usr/sbin/sendmail.postfix
[root@localhost Server]# postconf -e "mynetworks_style=subnet"
[root@localhost Server]# postconf -e mynetworks_style=host"
[root@localhost Server]# postconf -e mynetworks=192.168.0.254, 127/8"
[root@localhost Server]# service postfix restart
[root@localhost Server]# service sendmail stop (if you face postfix fail)
[root@localhost Server]# useradd sales
[root@localhost Server]# vim /etc/aliases
sales: u1,u2,u3
[root@localhost Server]# newaliases
[root@localhost Server]# vim /etc/postfix/main.cf
RELAY
OK
DENY
[root@localhost Server]# postconf -e smtp_recipient_restrictions=check
