How to add Port Forwarding Group of ports/protocols to your firewall:
First create a Port Forward Rule, go to Advanced/Security & Firewall/Port Forwarding Rule. Create a rule and add all the protocols/ports needed (e.g. L2TP) and save it. You'd think you could go to "Port Forwarding" and add it now but it doesn't show in the drop down list. Navigate to Advanced/Network Settings/Static NAT, create a rule adding your device, your public IP, select the check box "Enable Port Forwarding" then select the "Port Forwarding Rule" you created. It'll be on the drop down list. Apply your changes, navigate to Port Forwarding and you'll see a new Group rule was added. This worked perfectly for me to enable L2TP and all the protocols & ports it requires. I've attached some screen pics to help. Hope this helps, it was a pain to figure out.
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