Install postfix server on aws linux ami

postfix.sh

#!/bin/bash

DOMAIN=example.com
USERNAME=admin

# Configure hostname
sed s/"127.0.0.1   localhost"/"127.0.0.1   $DOMAIN localhost"/ -i /etc/hosts
sed s/HOSTNAME.*/HOSTNAME=$DOMAIN/ -i /etc/sysconfig/network

# Intall server and mutt
yum install -y postfix mutt

#Configure postfix
cp /etc/postfix/main.cf /etc/postfix/main.cf.bak
cat << EOF > /etc/postfix/main.cf
alias_database = hash:/etc/aliases
alias_maps = hash:/etc/aliases
command_directory = /usr/sbin
config_directory = /etc/postfix
daemon_directory = /usr/libexec/postfix
data_directory = /var/lib/postfix
debug_peer_level = 2
html_directory = no
inet_interfaces = all
inet_protocols = all
mail_owner = postfix
mailq_path = /usr/bin/mailq.postfix
manpage_directory = /usr/share/man
newaliases_path = /usr/bin/newaliases.postfix
queue_directory = /var/spool/postfix
readme_directory = /usr/share/doc/postfix-2.6.6/README_FILES
sample_directory = /usr/share/doc/postfix-2.6.6/samples
sendmail_path = /usr/sbin/sendmail.postfix
setgid_group = postdrop
unknown_local_recipient_reject_code = 550
mydestination = \$myhostname, localhost.\$mydomain, localhost, \$mydomain
mydomain = $DOMAIN
myhostname = $DOMAIN
mynetworks_style = host
myorigin = \$mydomain
EOF

#Add user for receive mail
adduser $USERNAME

# Start postfixpoweroff
chkconfig --add postfix
service sendmail
service postfix start