@average_joe said in Layer 3 Switch to pfSense - What Am I Missing?:
the NAT rule covers the LAN Net, but there was no NAT specified for the other VLANs in the 10.20.0.0/16 Supernet.
They would be if you were on automatic nat.. Had you changed this to manual? If so why? Once you create a gateway and create routes to the downstream nats they are automatically added for your outbound nat.
edit: Here you can see my auto outbound.. I then created a new downstream gateway off my dmz interface to 192.168.3.32.. I then created a route to downstream 172.16.0/24 network using that gateway and the outbound nats were auto added.
autonat.jpg
You can see that the outbound nats now include the 172.16.0/24 network to be be natted outbound.
That drawing Derelict posted - been around for many years that drawing ;) gives you all the info you would need for doing downstream networks with pfsense.
But yes you would need to modify the rules on your now transit network to allow the downstream network(s) on your firewall rules.