diff --git a/conf/main_ipv4.conf.sample b/conf/main_ipv4.conf.sample
index 7cae657..175fe53 100644
--- a/conf/main_ipv4.conf.sample
+++ b/conf/main_ipv4.conf.sample
@@ -360,6 +360,19 @@ mm_udp_ports_out="$stansard_mattermost_udp_ports_out"
 smtpd_ips=""
 forward_smtpd_ips=""
 
+# Additional Ports on which SMTP Service should lsiten
+#
+# blank separated list of ports
+#
+smtpd_additional_listen_ports=""
+
+# Additional Ports for outgoing smtp traffic
+#
+# blank separated list of ports
+#
+smtpd_additional_outgoung_ports=""
+
+
 # - Mail Services (smtps/pop(s)/imap(s)
 # -
 mail_server_ips=""
diff --git a/conf/main_ipv6.conf.sample b/conf/main_ipv6.conf.sample
index 7864ae4..989590a 100644
--- a/conf/main_ipv6.conf.sample
+++ b/conf/main_ipv6.conf.sample
@@ -376,6 +376,19 @@ mm_udp_ports_out="$stansard_mattermost_udp_ports_out"
 smtpd_ips=""
 forward_smtpd_ips=""
 
+# Additional Ports on which SMTP Service should lsiten
+#
+# blank separated list of ports
+#
+smtpd_additional_listen_ports=""
+
+# Additional Ports for outgoing smtp traffic
+#
+# blank separated list of ports
+#
+smtpd_additional_outgoung_ports=""
+
+
 # - Mail Services (smtps/pop(s)/imap(s)
 # -
 mail_server_ips=""
diff --git a/conf/post_decalrations.conf b/conf/post_decalrations.conf
index 7de53af..13c17f8 100644
--- a/conf/post_decalrations.conf
+++ b/conf/post_decalrations.conf
@@ -313,6 +313,24 @@ for _ip in $forward_smtpd_ips ; do
 done
 
 
+# ---
+# Additional SMTP Listen Ports
+# ---
+declare -a smtpd_additional_listen_port_arr
+for _port in $smtpd_additional_listen_ports ; do
+   smtpd_additional_listen_port_arr+=("$_port")
+done
+
+
+# ---
+# Additional SMTP Outgoing Ports
+# ---
+declare -a smtpd_additional_outgoung_port_arr
+for _port in $smtpd_additional_outgoung_ports ; do
+   smtpd_additional_outgoung_ports+=("$_port")
+don
+
+
 # ---
 # - IP Addresses XMPP Service (Jabber - Prosody)
 # ---
diff --git a/ip6t-firewall-server b/ip6t-firewall-server
index 7069985..4f13cd5 100755
--- a/ip6t-firewall-server
+++ b/ip6t-firewall-server
@@ -1671,6 +1671,29 @@ done
 echo_done
 
 
+# ---
+# - Mail (additional smtp ports OUT)
+# ---
+
+echononl "\t\tMail (additional smtp ports OUT)"
+
+if [[ ${#smtpd_additional_outgoung_port_arr[@]} -gt 0 ]] ; then
+
+   for _port in ${smtpd_additional_outgoung_port_arr[@]} ; do
+      for _dev in ${ext_if_arr[@]} ; do
+         $ip6t -A OUTPUT -o $_dev -p tcp --dport $_port -m state --state NEW -j ACCEPT
+         if $kernel_forward_between_interfaces ; then
+            $ip6t -A FORWARD -o $_dev -p tcp --dport $_port -m state --state NEW -j ACCEPT
+         fi
+      done
+   done
+
+   echo_done
+else
+   echo_skipped
+fi
+
+
 # ---
 # - Mail SMTP Server (Port 25) including Spam Control
 # ---
@@ -1727,6 +1750,29 @@ else
 fi
 
 
+# ---
+# - Mail (additional smtp ports IN)
+# ---
+
+echononl "\t\tMail (additional smtp ports IN)"
+
+if [[ ${#smtpd_additional_listen_ports[@]} -gt 0 ]] ; then
+
+   for _port in ${smtpd_additional_listen_ports[@]} ; do
+      for _dev in ${ext_if_arr[@]} ; do
+         $ip6t -A INPUT -i $_dev -p tcp --dport $_port -m state --state NEW -j ACCEPT
+         if $kernel_forward_between_interfaces ; then
+            $ip6t -A FORWARD -i $_dev -p tcp --dport $_port -m state --state NEW -j ACCEPT
+         fi
+      done
+   done
+
+   echo_done
+else
+   echo_skipped
+fi
+
+
 # ---
 # -  Mailservice (Submission/SMTPS/POP/IMAP Server)
 # ---
diff --git a/ipt-firewall-server b/ipt-firewall-server
index 7dfc6e7..9b6177d 100755
--- a/ipt-firewall-server
+++ b/ipt-firewall-server
@@ -1837,6 +1837,29 @@ done
 echo_done
 
 
+# ---
+# - Mail (additional smtp ports OUT)
+# ---
+
+echononl "\t\tMail (additional smtp ports OUT)"
+
+if [[ ${#smtpd_additional_outgoung_port_arr[@]} -gt 0 ]] ; then
+
+   for _port in ${smtpd_additional_outgoung_port_arr[@]} ; do
+      for _dev in ${ext_if_arr[@]} ; do
+         $ipt -A OUTPUT -o $_dev -p tcp --dport $_port -m state --state NEW -j ACCEPT
+         if $kernel_activate_forwarding ; then
+            $ipt -A FORWARD -o $_dev -p tcp --dport $_port -m state --state NEW -j ACCEPT
+         fi
+      done
+   done
+
+   echo_done
+else
+   echo_skipped
+fi
+
+
 # ---
 # - Mail SMTP Server (Port 25) including Spam Control
 # ---
@@ -1893,6 +1916,29 @@ else
 fi
 
 
+# ---
+# - Mail (additional smtp ports IN)
+# ---
+
+echononl "\t\tMail (additional smtp ports IN)"
+
+if [[ ${#smtpd_additional_listen_ports[@]} -gt 0 ]] ; then
+
+   for _port in ${smtpd_additional_listen_ports[@]} ; do
+      for _dev in ${ext_if_arr[@]} ; do
+         $ipt -A INPUT -i $_dev -p tcp --dport $_port -m state --state NEW -j ACCEPT
+         if $kernel_activate_forwarding ; then
+            $ipt -A FORWARD -i $_dev -p tcp --dport $_port -m state --state NEW -j ACCEPT
+         fi
+      done
+   done
+
+   echo_done
+else
+   echo_skipped
+fi
+
+
 # ---
 # - Mailservice (Submission/SMTPS/POP/IMAP Server)
 # ---