postfix configure

vi /etc/postfix/main.cf
inet_interfaces=all
#inet_interfaces=localhost
mydomain=example.com
myhostname=server.example.com
myneworks=192.168.1.0/24,127.0.0.0/8
relay-domains=$mydestination    * super important
mynetworks_style=host
myorigin=$mydomain
myorigin=$myhostname

use /etc/mail/access and then system-switch-mail to switch to postfix
rather than bothering config /etc/postfix/access

switch from sendmail to postfix
#alternatives --config mta    
check status
netstat -luntp|grep 25

#tail -f /var/log/maillog