#!/bin/bash
#########################################################

mgUSERNAME="MailGun Username"
mgPASSWORD="COMPLEX PASSWORD"
testEmail="user@example.com"

#########################################################

echo "Installing this agent may be dangerous, make sure this is the correct server!"
echo
epoch=`date +%s`
name=`hostname`
while true; do
    read -p "Enter the hostname of this server to confirm: '$name': " hn
    case $hn in
        $name* ) break;;
        * ) echo "Not correct, cancelled."; exit;;
    esac
done

apt-get update
apt-get upgrade
apt-get install postfix mailutils sasl2-bin libsasl2-2 ca-certificates libsasl2-modules
apt-get purge sendmail*

echo "`hostname`.local" > /etc/postfix/node-name

mv /etc/postfix/main.cf /etc/postfix/main.cf.$epoch.bak

cat > /etc/postfix/main.cf << EOL

smtpd_banner = Relay $name ESMTP Postfix (Ubuntu)
biff = no
myorigin = /etc/postfix/node-name
mydestination =
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128
inet_interfaces = loopback-only
relayhost = [smtp.mailgun.org]:587
smtp_sasl_auth_enable = yes
smtp_sasl_password_maps = static:$mgUSERNAME:$mgPASSWORD
smtp_sasl_security_options = noanonymous
smtp_tls_security_level = may
smtpd_tls_security_level = may
smtp_tls_note_starttls_offer = yes
smtpd_tls_CApath = /etc/ssl/certs

EOL

service postfix reload

echo "Test mail from MailGun" | mail -s "Test Mail" $testEmail

echo "Install Completed."