#! /bin/bash

#############################################################
#### PostFix (Sendonly) install Script for Oracle Linux, #### 
#### Centos/Redhat and Ubuntu Servers.                   ####       
####                                                     ####
#### Author: Phil Connor 02/10/2021                      ####
#### Contact: contact@mylinux.work                       ####
#### Version 1.20-12.13.22                               ####
####                                                     ####
#### To use this script chmod it to 755                  ####
#### or simply type bash <filename.sh>                   ####  
#############################################################

#############################
#### User Configurations ####
#############################
DomainName=myserver.mydomain.com        # <-- Name of the server you are configuring this on
EnableForw=yes                          # <-- Do you want the server to forward the mail (yes/no)
ForwardMail=my_email@mydomain.com       # <-- What is the email you want to forward to?

##########################
#### System Variables ####
##########################
macnf=/etc/postfix/main.cf
sslcerts=/etc/letsencrypt/live/$DomainName

if [ "$(command -v lsb_release)" ]; then
    OS=$(lsb_release -i | awk '{print $3}' | tr '[:upper:]' '[:lower:]')
    OSVER=$(lsb_release -r | awk '{print $2}' | awk -F. '{print $1}')
else 
    OS=$(grep PRETTY_NAME /etc/os-release | sed 's/PRETTY_NAME=//g' | tr -d '="' | awk '{print $1}' | tr '[:upper:]' '[:lower:]')
    OSVER=$(grep VERSION_ID /etc/os-release | sed 's/VERSION_ID=//g' | tr -d '="' | awk -F. '{print $1}')
fi

###########################################################
#### Detect Package Manger from OS and OSVer Variables ####
###########################################################
if [[ ${OS} = alma || ${OS} = amazon || ${OS} = centos || ${OS} = red || ${OS} = rocky || ${OS} = oracle ]]; then
	if [[ "${OSVER}" = 7 || "${OSVER}" = 7 ]]; then
		PAKMGR="yum -y"
	else
		PAKMGR="dnf -y"
	fi
elif [[ "${OS}" = ubuntu  || "${OS}" = debian ]]; then
	PAKMGR="apt -y"
fi

########################################################
#### Install PostFix, Configure and Start/Enable it ####
########################################################
if [[ "${OS}" = ubuntu  || "${OS}" = debian ]]; then
    echo "postfix postfix/mailname string $DomainName" | debconf-set-selections
    echo "postfix postfix/main_mailer_type string 'Internet Site'" | debconf-set-selections
    DEBIAN_FRONTEND=noninteractive $PAKMGR install postfix bsd-mailx
else
    $PAKMGR install postfix mailx
fi

sed -i "s/inet_interfaces = all/inet_interfaces = loopback-only/g" $macnf
postconf -e "myhostname = $DomainName"
sed -i "s/#myorigin = \$myhostname/myorigin = \$myhostname/g" $macnf
sed -i "s/mydestination = \$myhostname, domain-name.com, localhost.\$mydomain, localhost/mydestination = \$myhostname, $DomainName, localhost.\$mydomain, localhost/g" $macnf

systemctl enable --now postfix

hostnamectl set-hostname $DomainName
echo "Mail delivery test" | mail -s "[Server] New e-mail" $ForwardMail

if [ $EnableForw = yes ]; then
    sed -i "s/root: /root: $ForwardMail/g"
    newaliases
    systemctl restart postfix
fi

########################
#### Add Encryption ####
########################
function encrypt() {
    {
        $PAKMGR install certbot
        
        if [ "$(command -v ufw)" ]; then
            ufw allow http
        elif [ "$(command -v firewall-cmd)" ]; then
            firewall-cmd --zone=public --add-port=80/tcp
            firewall-cmd --zone=public --permanent --add-port=80/tcp
        elif [ "$(command -v iptables)" ]; then
            iptables -I INPUT -p tcp -m tcp –dport 80 -j ACCEPT
            service iptables save
            ip6tables -I INPUT -p tcp -m tcp –dport 80 -j ACCEPT
            service ip6tables save
            systemctl restart iptables ip6tables
        fi
        
        certbot certonly --standalone --rsa-key-size 4096 --agree-tos --preferred-challenges http -d $DomainName

        #### TLS parameters ####
        sed -i "s/smtpd_tls_cert_file=/etc/ssl/certs/ssl-cert-snakeoil.pem/smtpd_tls_cert_file=$sslcerts/fullchain.pem/g" $macnf
        sed -1 "s/smtpd_tls_key_file=/etc/ssl/private/ssl-cert-snakeoil.key/smtpd_tls_key_file=$sslcerts/privkey.pem/g" $macnf

        systemctl restart postfix

        echo "This is a test of an encrypted email" | mail -s "This is Just a Test" $ForwardMail
    }
}