PfSense alix2d13 D-Link DSL-300G+: no access to Internet

[rubbrduck]

Hi there,
just installed pfSense-1.2.3-RELEASE-4g-nanobsd.img.gz on an alix2d13 with zero problems, all interfaces recognized, everything was A-OK.

I am currently using a very old pc running Smoothwall. I'm happy with the performance but beside being noisy the pc draws a lot of power so it is very expensive to keep up and the Alix looked like the perfect solution to my problems.
After setting up everything I proceeded to connect the modem to the WAN interface.
To connect to the internet I use a D-Link dsl-300g+ modem.

So vr0 is LAN and vr1 is WAN.
The trouble is vr1 (connected to the ethernet port of the modem) fails to receive the outside address assigned from the ISP (Infostrada, Italy) that the modem should relay to it.

On Smoothwall the solution is setting up the red interface (equivalent to vr1 on pfSense) as dhcp client, and the modem (acting as a half-bridge) transfers the outside ip address of the ISP to the interface itself, so that the modem is completely transparent in the operation.

I assumed it would be the same on pfSense, but with the same setup the WAN interface is reported as up, I can see the "release" button but there's no traffic. In the logs I see DHCP discover messages, but no acknowledgment and the operation just times out.

I have tried everything that came to my mind to solve the problem: setting up the modem as a RFC 1483 and starting the connection from pfSense using vr1 as PPPoE, trying PPPoA on the modem in the hope that it would make a difference, etc.
I am at my wit's end.

Any insight?

Thanks.
Ciao, Luca.

[rubbrduck]

Using another appliance (Roper SuperLan adsl combo router) solved the problem.