#!/bin/sh # BEFORE INSTALLING # Have a Debian or Ubuntu server with a static IP and DNS records (usually # A/AAAA) that point your domain name to it. # NOTE WHILE INSTALLING # On installation of Postfix, select "Internet Site" and put in TLD (without # `mail.` before it). # AFTER INSTALLING # More DNS records will be given to you to install. One of them will be # different for every installation and is uniquely generated on your machine. umask 0022 apt-get install -y postfix postfix-pcre dovecot-imapd dovecot-sieve opendkim opendkim-tools spamassassin spamc net-tools fail2ban domain="$(cat /etc/mailname)" subdom=${MAIL_SUBDOM:-mail} maildomain="$subdom.$domain" certdir="/etc/letsencrypt/live/$maildomain" # Open required mail ports, and 80, for Certbot. for port in 80 993 465 25 587; do ufw allow "$port" 2>/dev/null done [ ! -d "$certdir" ] && possiblecert="$(certbot certificates 2>/dev/null | grep "Domains:\.* \(\*\.$domain\|$maildomain\)\(\s\|$\)" -A 2 | awk '/Certificate Path/ {print $3}' | head -n1)" && certdir="${possiblecert%/*}" [ ! -d "$certdir" ] && certdir="/etc/letsencrypt/live/$maildomain" && case "$(netstat -tulpn | grep ":80\s")" in *nginx*) apt install -y python3-certbot-nginx certbot -d "$maildomain" certonly --nginx --register-unsafely-without-email --agree-tos ;; *apache*) apt install -y python3-certbot-apache certbot -d "$maildomain" certonly --apache --register-unsafely-without-email --agree-tos ;; *) apt install -y python3-certbot certbot -d "$maildomain" certonly --standalone --register-unsafely-without-email --agree-tos ;; esac [ ! -d "$certdir" ] && echo "Error locating or installing SSL certificate." && exit 1 echo "Configuring Postfix's main.cf..." # Change the cert/key files to the default locations of the Let's Encrypt cert/key postconf -e "smtpd_tls_key_file=$certdir/privkey.pem" postconf -e "smtpd_tls_cert_file=$certdir/fullchain.pem" postconf -e "smtp_tls_CAfile=$certdir/cert.pem" # Enable, but do not require TLS. Requiring it with other server would cause # mail delivery problems and requiring it locally would cause many other # issues. postconf -e 'smtpd_tls_security_level = may' postconf -e 'smtp_tls_security_level = may' # TLS required for authentication. postconf -e 'smtpd_tls_auth_only = yes' # Exclude obsolete, insecure and obsolete encryption protocols. postconf -e 'smtpd_tls_mandatory_protocols = !SSLv2, !SSLv3, !TLSv1, !TLSv1.1' postconf -e 'smtp_tls_mandatory_protocols = !SSLv2, !SSLv3, !TLSv1, !TLSv1.1' postconf -e 'smtpd_tls_protocols = !SSLv2, !SSLv3, !TLSv1, !TLSv1.1' postconf -e 'smtp_tls_protocols = !SSLv2, !SSLv3, !TLSv1, !TLSv1.1' # Exclude suboptimal ciphers. postconf -e 'tls_preempt_cipherlist = yes' postconf -e 'smtpd_tls_exclude_ciphers = aNULL, LOW, EXP, MEDIUM, ADH, AECDH, MD5, DSS, ECDSA, CAMELLIA128, 3DES, CAMELLIA256, RSA+AES, eNULL' # Here we tell Postfix to look to Dovecot for authenticating users/passwords. # Dovecot will be putting an authentication socket in /var/spool/postfix/private/auth postconf -e 'smtpd_sasl_auth_enable = yes' postconf -e 'smtpd_sasl_type = dovecot' postconf -e 'smtpd_sasl_path = private/auth' # helo, sender, relay and recipient restrictions postconf -e "smtpd_sender_login_maps = pcre:/etc/postfix/login_maps.pcre" postconf -e 'smtpd_sender_restrictions = permit_sasl_authenticated, permit_mynetworks, reject_sender_login_mismatch, reject_unknown_reverse_client_hostname, reject_unknown_sender_domain' postconf -e 'smtpd_recipient_restrictions = permit_sasl_authenticated, permit_mynetworks, reject_unauth_destination, reject_unknown_recipient_domain' postconf -e 'smtpd_relay_restrictions = permit_sasl_authenticated, reject_unauth_destination' postconf -e 'smtpd_helo_required = yes' postconf -e 'smtpd_helo_restrictions = permit_mynetworks, permit_sasl_authenticated, reject_invalid_helo_hostname, reject_non_fqdn_helo_hostname, reject_unknown_helo_hostname' # NOTE: the trailing slash here, or for any directory name in the home_mailbox # command, is necessary as it distinguishes a maildir (which is the actual # directories that what we want) from a spoolfile (which is what old unix # boomers want and no one else). postconf -e 'home_mailbox = Mail/Inbox/' # Prevent "Received From:" header in sent emails in order to prevent leakage of public ip addresses postconf -e "header_checks = regexp:/etc/postfix/header_checks" # strips "Received From:" in sent emails echo "/^Received:.*/ IGNORE /^X-Originating-IP:/ IGNORE" >> /etc/postfix/header_checks # Create a login map file that ensures that if a sender wants to send a mail from a user at our local # domain, they must be authenticated as that user echo "/^(.*)@$(sh -c "echo $domain | sed 's/\./\\\./'")$/ \${1}" > /etc/postfix/login_maps.pcre # master.cf echo "Configuring Postfix's master.cf..." sed -i '/^\s*-o/d;/^\s*submission/d;/^\s*smtp/d' /etc/postfix/master.cf echo "smtp unix - - n - - smtp smtp inet n - y - - smtpd -o content_filter=spamassassin submission inet n - y - - smtpd -o syslog_name=postfix/submission -o smtpd_tls_security_level=encrypt -o smtpd_sasl_auth_enable=yes -o smtpd_tls_auth_only=yes smtps inet n - y - - smtpd -o syslog_name=postfix/smtps -o smtpd_tls_wrappermode=yes -o smtpd_sasl_auth_enable=yes spamassassin unix - n n - - pipe user=debian-spamd argv=/usr/bin/spamc -f -e /usr/sbin/sendmail -oi -f \${sender} \${recipient}" >> /etc/postfix/master.cf # By default, dovecot has a bunch of configs in /etc/dovecot/conf.d/ These # files have nice documentation if you want to read it, but it's a huge pain to # go through them to organize. Instead, we simply overwrite # /etc/dovecot/dovecot.conf because it's easier to manage. You can get a backup # of the original in /usr/share/dovecot if you want. mv /etc/dovecot/dovecot.conf /etc/dovecot/dovecot.backup.conf echo "Creating Dovecot config..." echo "# Dovecot config # Note that in the dovecot conf, you can use: # %u for username # %n for the name in name@domain.tld # %d for the domain # %h the user's home directory ssl = required ssl_cert = <$certdir/fullchain.pem ssl_key = <$certdir/privkey.pem ssl_min_protocol = TLSv1.2 ssl_cipher_list = "'EECDH+ECDSA+AESGCM:EECDH+aRSA+AESGCM:EECDH+ECDSA+SHA256:EECDH+aRSA+SHA256:EECDH+ECDSA+SHA384:EECDH+ECDSA+SHA256:EECDH+aRSA+SHA384:EDH+aRSA+AESGCM:EDH+aRSA+SHA256:EDH+aRSA:EECDH:!aNULL:!eNULL:!MEDIUM:!LOW:!3DES:!MD5:!EXP:!PSK:!SRP:!DSS:!RC4:!SEED'" ssl_prefer_server_ciphers = yes ssl_dh = /etc/dovecot/dovecot.conf # If using an old version of Dovecot, remove the ssl_dl line. case "$(dovecot --version)" in 1|2.1*|2.2*) sed -i '/^ssl_dh/d' /etc/dovecot/dovecot.conf ;; esac mkdir /var/lib/dovecot/sieve/ echo "require [\"fileinto\", \"mailbox\"]; if header :contains \"X-Spam-Flag\" \"YES\" { fileinto \"Junk\"; }" > /var/lib/dovecot/sieve/default.sieve grep -q '^vmail:' /etc/passwd || useradd vmail chown -R vmail:vmail /var/lib/dovecot sievec /var/lib/dovecot/sieve/default.sieve echo 'Preparing user authentication...' grep -q nullok /etc/pam.d/dovecot || echo 'auth required pam_unix.so nullok account required pam_unix.so' >> /etc/pam.d/dovecot # OpenDKIM # A lot of the big name email services, like Google, will automatically reject # as spam unfamiliar and unauthenticated email addresses. As in, the server # will flatly reject the email, not even delivering it to someone's Spam # folder. # OpenDKIM is a way to authenticate your email so you can send to such services # without a problem. # Create an OpenDKIM key in the proper place with proper permissions. echo 'Generating OpenDKIM keys...' mkdir -p "/etc/postfix/dkim/$domain" opendkim-genkey -D "/etc/postfix/dkim/$domain" -d "$domain" -s "$subdom" chgrp -R opendkim /etc/postfix/dkim/* chmod -R g+r /etc/postfix/dkim/* # Generate the OpenDKIM info: echo 'Configuring OpenDKIM...' grep -q "$domain" /etc/postfix/dkim/keytable 2>/dev/null || echo "$subdom._domainkey.$domain $domain:$subdom:/etc/postfix/dkim/$domain/$subdom.private" >> /etc/postfix/dkim/keytable grep -q "$domain" /etc/postfix/dkim/signingtable 2>/dev/null || echo "*@$domain $subdom._domainkey.$domain" >> /etc/postfix/dkim/signingtable grep -q '127.0.0.1' /etc/postfix/dkim/trustedhosts 2>/dev/null || echo '127.0.0.1 10.1.0.0/16' >> /etc/postfix/dkim/trustedhosts # ...and source it from opendkim.conf grep -q '^KeyTable' /etc/opendkim.conf 2>/dev/null || echo 'KeyTable file:/etc/postfix/dkim/keytable SigningTable refile:/etc/postfix/dkim/signingtable InternalHosts refile:/etc/postfix/dkim/trustedhosts' >> /etc/opendkim.conf sed -i '/^#Canonicalization/s/simple/relaxed\/simple/' /etc/opendkim.conf sed -i '/^#Canonicalization/s/^#//' /etc/opendkim.conf sed -i '/Socket/s/^#*/#/' /etc/opendkim.conf grep -q '^Socket\s*inet:12301@localhost' /etc/opendkim.conf || echo 'Socket inet:12301@localhost' >> /etc/opendkim.conf # OpenDKIM daemon settings, removing previously activated socket. sed -i '/^SOCKET/d' /etc/default/opendkim && echo "SOCKET=\"inet:12301@localhost\"" >> /etc/default/opendkim # Here we add to postconf the needed settings for working with OpenDKIM echo 'Configuring Postfix with OpenDKIM settings...' postconf -e 'smtpd_sasl_security_options = noanonymous, noplaintext' postconf -e 'smtpd_sasl_tls_security_options = noanonymous' postconf -e "myhostname = $maildomain" postconf -e 'milter_default_action = accept' postconf -e 'milter_protocol = 6' postconf -e 'smtpd_milters = inet:localhost:12301' postconf -e 'non_smtpd_milters = inet:localhost:12301' postconf -e 'mailbox_command = /usr/lib/dovecot/deliver' # A fix for "Opendkim won't start: can't open PID file?", as specified here: https://serverfault.com/a/847442 /lib/opendkim/opendkim.service.generate systemctl daemon-reload # Enable fail2ban security for dovecot and postfix. [ ! -f /etc/fail2ban/jail.d/emailwiz.local ] && echo "[postfix] enabled = true [postfix-sasl] enabled = true [sieve] enabled = true [dovecot] enabled = true" > /etc/fail2ban/jail.d/emailwiz.local for x in spamassassin opendkim dovecot postfix fail2ban; do printf "Restarting %s..." "$x" service "$x" restart && printf " ...done\\n" systemctl enable "$x" done pval="$(tr -d '\n' <"/etc/postfix/dkim/$domain/$subdom.txt" | sed "s/k=rsa.* \"p=/k=rsa; p=/;s/\"\s*\"//;s/\"\s*).*//" | grep -o 'p=.*')" dkimentry="$subdom._domainkey.$domain TXT v=DKIM1; k=rsa; $pval" dmarcentry="_dmarc.$domain TXT v=DMARC1; p=reject; rua=mailto:dmarc@$domain; fo=1" spfentry="$domain TXT v=spf1 mx a:$maildomain -all" mxentry="$domain MX 10 $maildomain 300" useradd -m -G mail dmarc # Create a cronjob that deletes month-old dmarc feedback: cat < /etc/cron.weekly/dmarc-clean #!/bin/sh find /home/dmarc/Mail -type f -mtime +30 -name '*.mail*' -delete EOF chmod 755 /etc/cron.weekly/dmarc-clean grep -q '^deploy-hook = echo "$RENEWED_DOMAINS" | grep -q' /etc/letsencrypt/cli.ini || echo " deploy-hook = echo \"\$RENEWED_DOMAINS\" | grep -q '$maildomain' && service postfix reload && service dovecot reload" >> /etc/letsencrypt/cli.ini echo "NOTE: Elements in the entries might appear in a different order in your registrar's DNS settings. $dkimentry $dmarcentry $spfentry $mxentry" > "$HOME/dns_emailwizard" printf "\033[31m _ _ | \ | | _____ ___ | \| |/ _ \ \ /\ / (_) | |\ | (_) \ V V / _ |_| \_|\___/ \_/\_/ (_)\033[0m Add these three records to your DNS TXT records on either your registrar's site or your DNS server: \033[32m $dkimentry $dmarcentry $spfentry $mxentry \033[0m NOTE: You may need to omit the \`.$domain\` portion at the beginning if inputting them in a registrar's web interface. Also, these are now saved to \033[34m~/dns_emailwizard\033[0m in case you want them in a file. Once you do that, you're done! Check the README for how to add users/accounts and how to log in.\n"