transparent

Yes you can. Just connect the Unraid Nic to a free port on the pfSense Nic. On my system, Unraid is using the build-in 1Gb Nic on the motherboard. I installed pfSence and added a 4 x 1Gb Intel Nic only in use by pfSense. (from eBay) 1. Cat-5 cable between the Unraid Nic and one of the ports on the 4 port Nic. In pfSense this port is then labeled Unraid. 2. Cat-5 cable on port 2 connected to the internet modem (Interface Name: Wan-internet). 3. Cat-5 cable on port 3 connected to my wireless access point (Interface name: WiFi. This gives wifi a separate lan that is restricted). 4. Added a 1 x 10Gb card that is also set up in pfSense. This card is sole in use by my Macbook. (also conveniently protected against traffic from the other interfaces, including wifi). I will try the virtual 10Gb trick for Unraid (which was the reason I installed pfSense, so I can pull video footage from Unraid at 10Gb speeds. I will report back, if successful.

May I recommend this guide from SpaceInvader One. It has a few years on its back, but still holds up in many cases.