1. From firmware version R_00.07.06.5

Since version 7.06.5, the forwarding rules are automatically added with the required source zone, which is already set in the dmz_fw rule. This means that even with an mdex fixed.IP+/public via OpenVPN, it is no longer possible to lose remote access to the router by subsequently activating DMZ. Additional "workaround" scripts are no longer required since version 7.06.5.

2. From firmware version R_00.07.05

2.1 Remote access to the router WebUI

When using an mdex fixed.IP+/public via OpenVPN with active DMZ, there are a few things to note:

• For routers preconfigured by mdex for an mdex fixed.IP+/public via OpenVPN, the correct source zone "openvpn" is already set for all relevant rules.
• However, if "DMZ" is subsequently deactivated, all the above port forwarding rules are automatically deleted because they are no longer required.
• If "DMZ" is now reactivated, the above rules are automatically recreated, but all with the "wrong" source zone wan!
• In order for access via an mdex fixed.IP/public.IP via OpenVPN to work again, the source zones of these rules must be manually changed from wan openvpn. The correct sequence must be followed so that remote access to the router is not lost:
  
  1. first change the source zone of the port forwarding rules dmz_http, dmz_https, dmz_ssh and dmz_snmp to wan openvpn.
  2. the source zone of the last rule dmz_fw can then be changed from wan openvpn without losing remote access. ¹

¹ A script is implemented under System -> Maintenance -> Custom Scripts for security purposes, which automatically adjusts the "source zone" of the rules dmz_http, dmz_https, dmz_ssh and dmz_snmp when the router is rebooted from wan openvpn if only the source zone of the rule dmz_fw has been changed to "openvpn". This means that remote access to the router is possible again at the latest after the next router reboot if the rule dmz_fw was accidentally changed to "openvpn" first. This script is included in all routers from firmware 7.05 that have been preconfigured as mdex fixed.IP+ / public.IP via OpenVPN.

System -> Maintenance -> Custom ScriptsSystem -> Maintenance -> Custom Scripts

System ->#!/bin/sh
# mdex workaround: If the rule "dmz_fwd" is enabled and set to openvpn, the other fw rules "dmz_http", "dmz_https", "dmz_ssh" and "dmz_snmp" are also set to openvpn after the next router reboot. 

. /lib/functions.sh
dmz_src=""
src_updated=0
find_dmz_src() {
   local section="$1"
   local name="$(uci_get firewall "$section" "name")"
   if [ "$name" = "dmz_fw" ]; then
      dmz_src="$(uci_get firewall "$section" "src")"
   fi
}

update_dmz_fwds() {
   local section="$1"
   local name="$(uci_get firewall "$section" "name")"
   if [ "$name" = "dmz_http" ] || [ "$name" = "dmz_https" ] || [ "$name" = "dmz_snmp" ] || [ "$name" = "dmz_ssh" ]; then
      local src="$(uci_get firewall "$section" "src")"
      if [ "$src" != "$dmz_src" ]; then
         uci_set "firewall" "$section" "src" "$dmz_src"
         src_updated=1
      fi
   fi
}
config_load "firewall"
config_foreach find_dmz_src "redirect"
[ -z "$dmz_src" ] && exit 0
config_foreach update_dmz_fwds "redirect"
[ "$src_updated" -eq 0 ] && exit 0
uci_commit "firewall"
/etc/init.d/firewall reload

exit 0

2.2 DMZ and port forwarding

3. From firmware version R_00.07.03

3.1 Remote access to the router WebUI

Network -> Firewall -> Custom RulesNetwork -> Firewall -> Custom Rules

#!/bin/ash
###################################################################################################
# mdex workaround for router remote access, if dmz_fw is enabled:

## Check HTTP remote acccess:
HTTP_PORT="$(/sbin/uci get uhttpd.main.listen_http)"
HTTP_REMOTE_STATUS="$(/sbin/uci get uhttpd.main._httpWanAccess)"
if [ "${HTTP_REMOTE_STATUS}" == '1' ] ; then
iptables -t nat -A PREROUTING -i + -p tcp --dport ${HTTP_PORT} -j REDIRECT --to-port ${HTTP_PORT}
fi

## Check HTTPS remote acccess:
HTTPS_PORT="$(/sbin/uci get uhttpd.main.listen_https)"
HTTPS_REMOTE_STATUS="$(/sbin/uci get uhttpd.main._httpsWanAccess)"
if [ "${HTTPS_REMOTE_STATUS}" == '1' ] ; then
iptables -t nat -A PREROUTING -i + -p tcp --dport ${HTTPS_PORT} -j REDIRECT --to-port ${HTTPS_PORT}
fi

## Check SSH remote access
SSH_PORT="$(/sbin/uci get dropbear.@dropbear[0].Port)"
SSH_REMOTE_STATUS="$(/sbin/uci get dropbear.@dropbear[0]._sshWanAccess)"
if [ "${SSH_REMOTE_STATUS}" == '1' ] ; then
iptables -t nat -A PREROUTING -i + -p tcp --dport ${SSH_PORT} -j REDIRECT --to-port ${SSH_PORT}
fi
 
## Check SNMP remote access:
SNMP_PORT="$(/sbin/uci get snmpd.general.port)"
SNMP_REMOTE_STATUS="$(/sbin/uci get snmpd.general.remoteAccess)"
SNMP_PROTOCOL="$(/sbin/uci get snmpd.general.proto)"
if [ "${SNMP_REMOTE_STATUS}" == '1' ] ; then
iptables -t nat -A PREROUTING -i + -p ${SNMP_PROTOCOL} --dport ${SNMP_PORT} -j REDIRECT --to-port ${SNMP_PORT}
fi
###################################################################################################

Please note the following information:

• When using an mdex fixed.IP+ / public.IP via OpenVPN, the source zone of the rule Enable_HTTPS_WAN or Enable_HTTP_WAN must be set to openvpn under Network -> Firewall -> Traffic Rules!
• Subsequent changes to the router remote access, e.g. port changes, only take effect after the next router restart. If subsequent changes are made via remote access, there is a risk that remote access to the router will be lost until the next router restart!
• When updating the firmware from a "Legacy FW" to the current "Factory FW" (R_00.07.xx), the above-mentioned script is not automatically updated. If the "Keep all settings" option is activated, only the current configuration settings and existing rules according to Remote access to the router WebUI (legacy firmware) are applied.

3.2 DMZ and port forwarding

4. Up to firmware version R_00.06 (legacy firmware)

4.1 Remote Access to the router WebUI

However, when using an mdex fixed.IP+ / public.IP via OpenVPN and DMZ Configuration, there are other things to be aware of:.

• The ports and protocols that are forwarded when DMZ Configuration is active (forwarding all ports and protocols), the additional (automatic) port forwarding rule tlt_allow_remote_https_through_DMZ for remote access to the router WebUI is preconfigured with the correct source zone "From any host in vpn".

• However, the soruce zone of this rule tlt_allow_remote_http(s)_through_DMZ will be changed by the router to wan if configuration adjustments were subsequently made to remote access or port forwarding and the firewall or updated by clicking Save, e.g.:
  • An additional port forwarding rule is added although DMZ Configuration is still activated.
  • DMZ Configuration" is subsequently deactivated and then reactivated.
  • DMZ Configuration" was deactivated at the time of delivery and is now subsequently activated.
  • The router remote access was deactivated and is now subsequently activated.
    

• Remote access to the router's web interface via the mdex fixed.IP+/public.IP via OpenVPN is now no longer possible!
  In order for remote access to work again, the rule tlt_allow_remote_http(s)_through_DMZ must be manually switched back to Source "From any host in vpn" under Network -> Firewall in the Port Forwarding tab!

4.1.1 Changing the Router LAN IP Address or HTTP(S) Port

4.1.2 Disable Remote Access

1. deactivate Remote Settings under System -> Administration in the tab Access Control:

   WebUI
   Enable remote HTTP access:		Disable HTTP remote access to the WebUI of the router
   Enable remote HTTPS access:		Disable HTTPS remote access to the router's WebUI

   
   1. under Network -> Firewall in the tab Port Forwarding disable the rule Router Remote Access:
   

4.1.3 Enable Remote Access

1. activate remote settings under System -> Administration in the tab Access Control:

   WebUI
   Enable remote HTTPS access:		Enable HTTPS remote access to the WebUI of the router
   Port:	4444	HTTPS port of the router

   
   
2. activate the rule Router Remote Access under Network -> Firewall in the tab Port Forwarding (and adjust with Edit if necessary).
   
   
   • If the router LAN IP address and/or the HTTPS port have been changed in the meantime, this rule must be adjusted accordingly with Edit.
   • If this rule is missing, it must be added manually with New Port Forward Rule:

     New Port Forwarding Rule
     Name:	Router Remote Access
     Protocol:	TCP
     Source zone:	vpn
     External Port:	Port for external remote access to the router (e.g. 4444)
     Internal zone:	lan
     Internal IP address:	router LAN IP address (e.g. 192.168.1.1)
     Internal port:	HTTP/S port of the router (e.g. 4444)

4.2 DMZ Configuration (Forwarding of all Ports & Protocols)

4.3 Port Forwarding

1. under Network -> Firewall, deactivate the DMZ Configuration option so that all ports not covered in the port forwarding table are no longer forwarded to this terminal device.
   
   
2. Under Network -> Firewall in the tab Port Forwarding add a new port forwarding rule with Add.
   
3. For each port forwarding rule added, now click on Edit and change the Source zone from wan: wan to vpn: openvpn !:
   
   Only then is the terminal device accessible via the mdex fixed.IP+ / public.IP via OpenVPN.