No NAT after fresh install

[mcardinal]

Good evening,

I have a fair bit of experience with pfSense, having done multiple setups for commercial and production environments. I wanted to give OPNsense a go and I got stumped quite early in the setup. I re-installed twice and I really don't understand what I'm missing... I'm hoping someone will point it out.

Currently running OPNsense 23.1.7_3-amd64 (no updates available)

This is a double NAT setup but you'll see that I'm not even through the first one.

BELL FTTH Modem (192.168.99.1/24)
OPNsense WAN configured in DHCP (receiving 192.168.99.17/24)
OPNsense LAN configured in static (192.168.100.1/24)
Computer (tried static and with DHCP 192.168.100.50/24)

Based on another post I found (just in case), on the WAN interface I checked/unchecked "Block private networks" and "Block bogon networks", to finally leave them unchecked. The tests that follow are successful from the OPNsense box itself, I even managed to check for updates and apply.

That's about it but from the computer I've been running tests:

ping 192.168.99.1 (modem) : FAIL
ping 192.168.99.17 (OPNsense WAN) : FAIL
ping 192.168.100.1 (OPNsense LAN) : WORKS
nslookup google.com 192.168.100.1 (DNS to OPNsense): WORKS
nslookup google.com 8.8.8.8 (DNS to google) : FAIL
curl 192.168.99.1 (modem) : FAIL

Checked the Firewall Rules for LAN and WAN, I don't see anything related to bogons in the auto section. The "pf" process is also running as I would expect for a box that is expected to do natting.

Is anything missing here? I haven't touched anything under Firewall (NAT / Rules) and I would expect a simple setup like that to just work.

Best regards