diff --git a/seqs/mailserver.cfg.example b/seqs/mailserver.cfg.example
index f5421d9..59b85f6 100644
--- a/seqs/mailserver.cfg.example
+++ b/seqs/mailserver.cfg.example
@@ -2,20 +2,40 @@
 
 # MAS = Mail Server
 
-MAS_DOMAIN="mydomain.com"
-MAS_RELAYHOST=
-MAS_RELAYUSER=
-MAS_RELAYPASS=
+readonly MAS_DOMAIN="mydomain.com"
+readonly MAS_RELAYHOST=
+readonly MAS_RELAYUSER=
+readonly MAS_RELAYPASS=
 
-MAS_DBUSER='pfa'
-MAS_DBPASS='pass'
-MAS_DBNAME='pfa_db'
-MAS_mysql_virtual_domains_maps="user = '\$MAS_DBUSER'
-password = '\$MAS_DBPASS'
-hosts = localhost
-dbname = '\$MAS_DBNAME'
-query = SELECT domain FROM domain WHERE domain='%s' AND active = '1'
+# Settings for virtualizing mailboxes and domains
+
+readonly MAS_DBUSER='pfa'
+readonly MAS_DBPASS='pass'
+readonly MAS_DBNAME='pfa_db'
+readonly MAS_DBHOST='localhost'
+readonly MAS_VIRTUAL_USER='vmail'
+readonly MAS_VIRTUAL_USER_ID='5000'
+readonly MAS_VIRTUAL_FOLDER_BASE='/var/vmail'
+readonly MAS_VIRTUAL_USER_PART="user=$MAS_DBUSER
+password=$MAS_DBPASS
+hosts=$MAS_DBHOST
+dbname=$MAS_DBNAME"
+
+MAS_mysql_virtual_domains_maps="query = SELECT domain FROM domain WHERE domain='%s' AND active = '1'
 #query = SELECT domain FROM domain WHERE domain='%s'
 #optional query to use when relaying for backup MX
 #query = SELECT domain FROM domain WHERE domain='%s' AND backupmx = '0' AND active = '1'
 #expansion_limit = 100"
+
+MAS_mysql_virtual_mailbox_maps="query = SELECT maildir FROM mailbox WHERE username='%s' AND active = '1'
+#expansion_limit = 100"
+
+MAS_mysql_virtual_alias_domain_mailbox_maps="query = SELECT maildir FROM mailbox,alias_domain WHERE alias_domain.alias_domain = '%d' and mailbox.username = CONCAT('%u', '@', alias_domain.target_domain) AND mailbox.active = 1 AND alias_domain.active='1'"
+
+MAS_mysql_virtual_alias_maps="query = SELECT goto FROM alias WHERE address='%s' AND active = '1'
+#expansion_limit = 100"
+
+MAS_mysql_virtual_alias_domain_maps="query = SELECT goto FROM alias,alias_domain WHERE alias_domain.alias_domain = '%d' and alias.address = CONCAT('%u', '@', alias_domain.target_domain) AND alias.active = 1 AND alias_domain.active='1'"
+
+MAS_mysql_virtual_alias_domain_catchall_maps="# handles catch-all settings of target-domain
+query = SELECT goto FROM alias,alias_domain WHERE alias_domain.alias_domain = '%d' and alias.address = CONCAT('@', alias_domain.target_domain) AND alias.active = 1 AND alias_domain.active='1'"
diff --git a/seqs/mailserver.sh b/seqs/mailserver.sh
index 53e2b8d..343bed3 100755
--- a/seqs/mailserver.sh
+++ b/seqs/mailserver.sh
@@ -6,36 +6,34 @@
 # MDA = Mail Delivery Agent (dovecot)
 # MUA = Mail User Agent (Mail program used by the user)
 
-toolName=mailserver
-mtaName=postfix
-mtaUser=postfix
-mtaDeps="$mtaName $mtaName-mysql"
-mtaConfLoc="/etc/$mtaName"
-mtaMysqlConfLoc="$mtaConfLoc/sql"
-mdaName=dovecot
-mdaConfLoc="/etc/$mdaName"
-mdaConfDir="$mdaConfLoc/conf.d"
-mdaDeps="dovecot-imapd dovecot-lmtpd dovecot-mysql dovecot-managesieved dovecot-sieve"
+readonly toolName=mailserver
+readonly mtaName=postfix
+readonly mtaUser=postfix
+readonly mtaDeps="$mtaName $mtaName-mysql"
+readonly mtaConfLoc="/etc/$mtaName"
+readonly mtaMysqlConfLoc="$mtaConfLoc/sql"
+readonly mdaName=dovecot
+readonly mdaConfLoc="/etc/$mdaName"
+readonly mdaConfDir="$mdaConfLoc/conf.d"
+readonly mdaDeps="dovecot-imapd dovecot-lmtpd dovecot-mysql dovecot-managesieved dovecot-sieve"
 
-# Get script working directory
-# (when called from a different directory)
-WDIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >>/dev/null 2>&1 && pwd )"
-CONFIG=0
-CONFIG_FILE_NAME="${toolName}.cfg"
-CONFIG_FILE_TEMPLATE="$WDIR/${CONFIG_FILE_NAME}.example"
+sq_aptOpt=
+sq_config=0
 
 seq_config() {
-  if [ $(id -u) -ne 0 ] ; then
-    endReturn -o 1 "No root"
-  fi
-  initSeqConfig "$CONFIG_FILE_NAME" "$CONFIG_FILE_TEMPLATE"
-  if [ $? -eq 0 ] ; then
-    CONFIG=1
+  root || endReturn -o 1 "No root"
+
+  #initSeqConfig "$CONFIG_FILE_NAME" "$CONFIG_FILE_TEMPLATE"
+  if initSeqConfig "${seq_configName:?}" "${seq_configTemplate:?}" ; then
+    sq_config=1
     info "     Domain: ${MAS_DOMAIN:-}"
-  elif [ $? -eq 1 ] ; then
-    # Config $CONFIG_FILE_NAME created. Needs modification first
-    dry || return -1
+  else
+    dry || return 1
   fi
+  
+  ## Apt cmdline option to suppress user interaction
+  interactive || sq_aptOpt="-y"
+
   return 0
 }
 
@@ -47,21 +45,16 @@ step_1() {
 
 step_2_info() { echo "Install $mtaName"; }
 step_2() {
-  local aptOpt=
-  if quiet;then
-    aptOpt="-y"
-  else
-    read -p "In the following dialog chose \"Internet site\" and enter $MAS_DOMAIN as your domain. Enter to continue..."
-  fi
-  exe apt install $mtaDeps $aptOpt
+  confirm -n -y "In the following dialog chose \"Internet site\" and enter $MAS_DOMAIN as your domain. Enter to continue..."
+  exe apt install $mtaDeps ${sq_aptOpt:-}
 }
 
 step_3_info() { echo "Enable $mtaName"; }
 step_3() {
   exe systemctl enable $mtaName
-  echo -e " [I] Printing $mtaName status\n"
+  info "Printing $mtaName status"
   exe service $mtaName status
-  echo -e "\n [I] Installed postfix version: $(postconf mail_version)"
+  info "Installed postfix version: $(postconf mail_version)"
 }
 
 step_4_info() { echo "$mtaName basic domain configuration"; }
@@ -74,17 +67,18 @@ step_4() {
 
 step_5_info() { echo "$mtaName enable submission service"; }
 step_5() {
-  info -e " [I] Copy following lines...\n"
+  local mtaConfSubmission="${seq_origin:?}/$toolName/submissionService"
+  local mtaConfSmtps="${seq_origin:?}/$toolName/smtpsService"
+
+  info "Copy following lines..."
   exe cat "$mtaConfSubmission"
-  exe read -rep $'\nPress Enter to open the '$mtaConfLoc'/master.cf'
-  exe vi $mtaConfLoc/master.cf
-  exe info
+  confirm -n -y "Press Enter to open the $mtaConfLoc/master.cf"
+  editor $mtaConfLoc/master.cf
+  info
   exe cat "$mtaConfSmtps"
-  exe read -rep $'\nPress Enter to open the '$mtaConfLoc'/master.cf'
-  exe vi $mtaConfLoc/master.cf
+  confirm -n -y "Press Enter to open the $mtaConfLoc/master.cf"
+  editor $mtaConfLoc/master.cf
 }
-mtaConfSubmission="$WDIR/$toolName/submissionService"
-mtaConfSmtps="$WDIR/$toolName/smtpsService"
 
 step_6_info() { echo "Configure TLS"; }
 step_6() {
@@ -111,8 +105,8 @@ step_7() {
 
 step_8_info() { echo "Install $mdaName"; }
 step_8() {
-  exe apt install $mdaDeps
-  info -e "\n [I] Installed version: $(dovecot --version)"
+  exe apt install $mdaDeps ${sq_aptOpt}
+  info "Installed version: $(dovecot --version)"
 }
 
 step_9_info() {
@@ -207,18 +201,11 @@ step_20_info() {
 }
 step_20_alias() { echo "virtual"; }
 step_20() {
-  local qOpt=
-  if quiet ; then
-    qOpt="-q"
-  fi
-  exe $WDIR/postfixadmin.sh ${qOpt} install
+  exe ${seq_origin:?}/postfixadmin.sh ${sqr_args} install
 }
 
 step_21_info() { echo "Create $mtaName mysql query files"; }
 step_21() {
-  # eval needed to expand sourced configuration variables
-  local localMysqlUser=`eval "echo \"$MAS_VIRTUAL_USER_PART\""`
-
   exe mkdir -p "$mtaMysqlConfLoc"
 
   local mtaFile
@@ -232,11 +219,10 @@ step_21() {
     "mysql_virtual_alias_domain_catchall_maps"\
   )
 
-  for mtaFile in ${mtaMysqlFiles[@]}
-  do
-    eval 'mtaVar=$MAS_'${mtaFile}
+  for mtaFile in ${mtaMysqlFiles[@]} ; do
+    mtaVar="MAS_${mtaFile}"
     info "creating ${mtaFile}.cf"
-    exe echo -e "$localMysqlUser\n$mtaVar" > "$mtaMysqlConfLoc/${mtaFile}.cf"
+    exep echo -e "${MAS_VIRTUAL_USER_PART:?}\n${!mtaVar:?}" \> "$mtaMysqlConfLoc/${mtaFile}.cf"
   done
 
   exe chown -R root:${mtaUser} "$mtaMysqlConfLoc"
@@ -273,65 +259,73 @@ step_23() {
 
 step_24_info() { echo "$mdaName virtualisation configuration instructions"; }
 step_24() {
-  echo "# Configuring Mailbox Location"
-  echo "  [/etc/dovecot/conf.d/10-mail.conf]"
-  echo "   mail_location = maildir:~/Maildir"
-  echo "   mail_home = ${MAS_VIRTUAL_FOLDER_BASE}/%d/%n"
-  echo
-  echo "# Configure authentication"
-  echo "  [/etc/dovecot/conf.d/10-auth.conf]"
-  echo "   # Username with domain"
-  echo "   auth_username_format = %u"
-  echo "   # Find and uncomment following line"
-  echo "   !include auth-sql.conf.ext"
-  echo "   # Comment following line to prevent local users from sending mail"
-  echo "   # without having registered an email address"
-  echo "   #!include auth-system.conf.ext"
-  echo "   # Debug login issues in /var/log/maillog by adding:"
-  echo "   auth_debug = yes"
-  echo "   auth_debug_passwords = yes"
-  echo
-  echo "# Adding mysql login information"
-  echo "  [/etc/dovecot/dovecot-sql.conf.ext]"
-  echo "   driver = mysql"
-  echo "   connect = host=$MAS_DBHOST dbname=$MAS_DBNAME user=$MAS_DBUSER password='${MAS_DBPASS}'"
-  echo "   default_pass_scheme = MD5"
-  echo "   password_query = SELECT username AS user,password FROM mailbox WHERE username = '%u' AND active='1'"
-  echo "   user_query = SELECT maildir, $MAS_VIRTUAL_USER_ID AS uid, $MAS_VIRTUAL_USER_ID AS gid FROM mailbox WHERE username = '%u' AND active='1'"
-  echo "   iterate_query = SELECT username AS user FROM mailbox"
+  color green
+  cat <<END_STEP24
+# Configuring Mailbox Location
+  [/etc/dovecot/conf.d/10-mail.conf]
+   mail_location = maildir:~/Maildir
+   mail_home = ${MAS_VIRTUAL_FOLDER_BASE}/%d/%n
+
+# Configure authentication
+  [/etc/dovecot/conf.d/10-auth.conf]
+   # Username with domain
+   auth_username_format = %u
+   # Find and uncomment following line
+   !include auth-sql.conf.ext
+   # Comment following line to prevent local users from sending mail
+   # without having registered an email address
+   #!include auth-system.conf.ext
+   # Debug login issues in /var/log/maillog by adding:
+   auth_debug = yes
+   auth_debug_passwords = yes
+
+# Adding mysql login information
+  [/etc/dovecot/dovecot-sql.conf.ext]
+   driver = mysql
+   connect = host=$MAS_DBHOST dbname=$MAS_DBNAME user=$MAS_DBUSER password='${MAS_DBPASS}'
+   default_pass_scheme = MD5
+   password_query = SELECT username AS user,password FROM mailbox WHERE username = '%u' AND active='1'
+   user_query = SELECT maildir, $MAS_VIRTUAL_USER_ID AS uid, $MAS_VIRTUAL_USER_ID AS gid FROM mailbox WHERE username = '%u' AND active='1'
+   iterate_query = SELECT username AS user FROM mailbox
+
+END_STEP24
 }
 
 step_25_info() {
   echo "Configure sieve for virtual users"
 }
 step_25() {
-  echo "# Sieve script configuration"
-  echo "  [$mdaConfDir/90-sieve.conf]"
-  echo "   sieve = file:/var/vmail/%d/%n/sieve;active=/var/vmail/%d/%n/.dovecot.sieve"
-  echo "   sieve_extensions = +notify +imapflags +vnd.dovecot.execute"
-  echo "   sieve_plugins = sieve_extprograms"
-  echo "   sieve_user_log = file:/var/vmail/%d/%n/sieve/sieve.log"
-  echo
-  echo "# Enable sieve for lmtp"
-  echo "  [$mdaConfDir/20-lmtp.conf]"
-  echo "   postmaster_address = postmaster@$MAS_DOMAIN"
-  echo "   mail_plugins = $mail_plugins sieve"
-  echo
-  echo "# Enable excution of external programs (e.g. to send xmpp messages on certain keywords)"
-  echo "  [$mdaConfDir/90-sieve-extprograms.conf]"
-  echo "   sieve_execute_bin_dir = /usr/lib/dovecot/sieve-execute"
-  echo
-  echo "# Notes on execution of scripts"
-  echo "  * Scripts are executed with the $MAS_VIRTUAL_USER user"
-  echo "  * Scripts must no be writeable by others"
-  echo "    (chown root:$MAS_VIRTUAL_USER script; chmod 750 script)"
-  echo "  * \$HOME is set to the virtual users home"
-  echo "    (e.g. /var/vmail/$MAS_DOMAIN/max)"
-  echo
-  echo "# Notes about sendxmpp"
-  echo "  * .sendxmpprc resides in every virtual users home"
-  echo "    and must be owned by $MAS_VIRTUAL_USER"
-  echo "    (chown $MAS_VIRTUAL_USER: .sendxmpprc; chmod 700 .sendxmpprc)"
+  color green
+  cat << END_STEP25
+# Sieve script configuration
+  [$mdaConfDir/90-sieve.conf]
+   sieve = file:/var/vmail/%d/%n/sieve;active=/var/vmail/%d/%n/.dovecot.sieve
+   sieve_extensions = +notify +imapflags +vnd.dovecot.execute
+   sieve_plugins = sieve_extprograms
+   sieve_user_log = file:/var/vmail/%d/%n/sieve/sieve.log
+
+# Enable sieve for lmtp
+  [$mdaConfDir/20-lmtp.conf]
+   postmaster_address = postmaster@$MAS_DOMAIN
+   mail_plugins = \$mail_plugins sieve
+
+# Enable excution of external programs (e.g. to send xmpp messages on certain keywords)
+  [$mdaConfDir/90-sieve-extprograms.conf]
+   sieve_execute_bin_dir = /usr/lib/dovecot/sieve-execute
+
+# Notes on execution of scripts
+  * Scripts are executed with the $MAS_VIRTUAL_USER user
+  * Scripts must no be writeable by others
+    (chown root:$MAS_VIRTUAL_USER script; chmod 750 script)
+  * \$HOME is set to the virtual users home
+    (e.g. /var/vmail/$MAS_DOMAIN/max)
+
+# Notes about sendxmpp
+  * .sendxmpprc resides in every virtual users home
+    and must be owned by $MAS_VIRTUAL_USER
+    (chown $MAS_VIRTUAL_USER: .sendxmpprc; chmod 700 .sendxmpprc)
+
+END_STEP25
 }
 
 step_50_info() { echo "Adding default relay host for sending mails"; }
@@ -355,12 +349,12 @@ step_52_info() {
 step_52_alias() { echo "client_access"; }
 step_52() {
   if [ ! -f "$mtaClientAccessLoc" ] ; then
-    echo " [I] Generating $mtaClientAccessLoc"
-    exep "echo \"# myhost.lan OK\" > \"$mtaClientAccessLoc\""
-    echo " [I] Don't forget to add the following"
-    echo "     [$mtaConfLoc/main.cf]"
-    echo "      smtpd_relay_restrictions ="
-    echo "          check_client_access hash:$mtaClientAccessLoc"
+    info "Generating $mtaClientAccessLoc"
+    exep echo "# myhost.lan OK" \> "$mtaClientAccessLoc"
+    info    "Don't forget to add the following"
+    info -a "[$mtaConfLoc/main.cf]"
+    info -a "  smtpd_relay_restrictions ="
+    info -a "      check_client_access hash:$mtaClientAccessLoc"
   fi
   info "Updating $mtaClientAccessLoc"
   exe postmap "$mtaClientAccessLoc"
@@ -375,10 +369,10 @@ step_54() {
   if [ ! -f "$mtaRecipientAccessLoc" ] ; then
     info "Generating $mtaRecipientAccessLoc"
     exep "echo \"# unwanted@${MAS_DOMAIN} 550 No mailbox. Nothing to see here.\" > \"$mtaRecipientAccessLoc\""
-    echo " [I] Don't forget to add the following"
-    echo "     [$mtaConfLoc/main.cf]"
-    echo "      smtpd_recipient_restrictions ="
-    echo "          check_recipient_access hash:$mtaRecipientAccessLoc"
+    info    "Don't forget to add the following"
+    info -a "[$mtaConfLoc/main.cf]"
+    info -a " smtpd_recipient_restrictions ="
+    info -a "     check_recipient_access hash:$mtaRecipientAccessLoc"
   fi
   info "Updating $mtaRecipientAccessLoc"
   exe postmap "$mtaRecipientAccessLoc"
@@ -397,10 +391,10 @@ step_56() {
     exe postconf -e "smtp_sasl_mechanism_filter = plain"
     exe postconf -e "smtp_tls_security_level = encrypt"
     exe postconf -e "smtp_tls_mandatory_ciphers = high"
-    echo " [I] Don't forget to add credentials for the new relay"
-    echo "     [$saslPassFile]"
-    echo "      user@extern.com username:passwort"
-    echo "     postmap $saslPassFile"
+    info    "Don't forget to add credentials for the new relay"
+    info -a "[$saslPassFile]"
+    info -a " user@extern.com username:passwort"
+    info -a "postmap $saslPassFile"
   fi
   info "Updating $mtaSenderRelayLoc"
   exe postmap "$mtaSenderRelayLoc"
@@ -423,21 +417,17 @@ step_100() {
       -f)
         shift
         fromAdr="-f ${1:-} "
-        shift
-        ;;
+        shift ;;
       -u)
         shift
         asUser="sudo -u ${1:-} "
-        shift
-        ;;
+        shift ;;
       *)
-        break
-        ;;
+        break ;;
     esac
   done
-  if [ -n "${1:-}" ] ; then
-    toAdr="$1"
-  fi
+  [ -n "${1:-}" ] && toAdr="$1"
+
   exe ${asUser}sh -c "echo \"Subject: Test from Postfix\nIt is \$(date)\n\nGreetings \$(whoami)\" | sendmail ${fromAdr}$toAdr"
 }
 
@@ -455,11 +445,11 @@ step_104_alias() { echo "delqueue"; }
 step_104() {
   shift
   local msgId="ALL"
-  if [ -n "${1:-}" ] ; then
-    msgId="$1"
-  fi
+  [ -n "${1:-}" ] && msgId="$1"
   exe postsuper -d "$msgId"
 }
 
+# shellcheck disable=SC2034 # Appears unused
 readonly sqr_minVersion=16
+# shellcheck disable=SC1091 # Don't follow this source
 . /usr/local/bin/sequencer.sh