Setup Guide: Synology Router in DHCP Mode

Step 1: Change DNS on Router

Login to Synology Router and go to Network Center.  In Local Network, go to General. Here you will need to change the default DNS from the Gateway address to something else, e.g. 8.8.8.8 or 1.1.1.1

After the change, please tap on Apply.

Step 2: Setup Firewalla Box with DHCP Mode

Follow the Installation Guide to install Firewalla Box. 

After scanning the QR Code, tap on "Manual Setup" and setup Firewalla with DHCP Mode.

Step 3: Disable DHCP Server on Router

Disable DHCP Server on Synology Router. Login to Synology Router -> Local Network -> DHCP Server -> Disabled 

Some devices may take a while to migrate to the new network space.
You can rejoin your devices to the network to get IP addresses from Firewalla's overlay network, the IP address will change to 192.168.218.x