Port forward automation using Event Juggler

Introdutcion

This configuration example demonstrates how to automate port forwarding using the Event Juggler function on Teltonika devices. By leveraging this feature, users can automatically create a port forwarding rule for the most recent DHCP lease IP address. This is especially useful in dynamic network environments, as it eliminates the need for manual updates and significantly reduces setup time during on-site deployments.

Port_forward script

The script used in this setup utilizes UCI commands to create a new firewall port forwarding rule, which is applied to the most recent IP address lease from the router's DHCP server. For instructions on creating a runnable script file, refer to our configuration example article - User Scripts examples.

#!/bin/sh                                                               
                                               
LAN_INTERFACE="br-lan"  # Adjust if needed                               
FORWARD_PORT=8080       # External port to forward                       
DEST_PORT=443           # Internal port on the target device           
PROTO="tcp"             # Protocol (tcp, udp, both)

RULE_NAME="DHCP_Forward"

                    
LATEST_LEASE=$(head -n 1 /tmp/dhcp.leases | awk '{print $3}')      
LEASE_IP=$(head -n 1 /tmp/dhcp.leases | awk '{print $3}')                          
if [ -z "$LEASE_IP" ]; then
   echo "No DHCP leases found. Exiting."                                 
   exit 1
fi  

#Remove existing port forward rule if it exists                         
uci delete firewall.$RULE_NAME 2>/dev/null 
                                          
uci set firewall.$RULE_NAME="redirect"                                   
uci set firewall.$RULE_NAME.name="$RULE_NAME"                             
uci set firewall.$RULE_NAME.src="wan"                                     
uci set firewall.$RULE_NAME.src_dport="$FORWARD_PORT"                     
uci set firewall.$RULE_NAME.dest="lan"                                   
uci set firewall.$RULE_NAME.dest_ip="$LEASE_IP"                           
uci set firewall.$RULE_NAME.dest_port="$DEST_PORT"                       
uci set firewall.$RULE_NAME.proto="$PROTO"

uci commit firewall          
/etc/init.d/firewall restart 

Event juggler configuration

To begin with open router's WebUI, navigate to Services → Event juggler and creat a new instance by entering the name and clicking on "Add" button.

Event data configuration

After creating a new event juggler instance, you will be redirected to the event data configuration window. In this window select the following options:

1. Enable - On
2. Event type - Log
3. Events logs type - Port state
4. Events log subtype - LAN1 (depending on the specific port you want to monitor)
5. Click on Save & Apply

Action data configuration

In this setup, we’ll use multiple actions triggered by changes in the LAN1 port status. The first action will run a script stored on the router, which creates a custom port forwarding rule for the latest IP lease. The second action will trigger when the LAN1 port goes DOWN, sending an SMS notification to a specific recipient to let them know the device has been disconnected or is no longer detected on the LAN1 port.