Firewall/NAT

Hi,

I think my problem is more related to Firewall/NAT than VPN, so I posted it here.

Situation:
PC (VPN-Client) => m0n0wall => VPN gateway

My problem:
I can't connect to the VPN gateway. I've tried with vpnc and the Cisco VPN Client, but both don't get an answer from the gateway.
I've tried it behind a D-Link DIR-100 and it works fine, so it have to be a problem with m0n0wall.

There's nothing in the logs. I enabled "Allow fragmented IPsec packets" and IPsec, but no changes.

I hope you can help me... Thanks.

achnoe