Masquerading from LAN to OPT1

[decibel83]

Hi!
What about if I wish to have masquerading from the LAN interface to the OPT1 interface?
I have a Soekris net4501 system with 3 network interfaces.
The first network is the LAN, the second one is the WAN and the third one is another network (OPT1) which the LAN clients needs to connect to.
I can reach the WAN from the LAN, but I can't reach any host on the OPT1 from any LAN client.

The OPT1 has 172.18.67.252/24 as IP address, and I can ping an host (for example 172.18.67.254) from the m0n0wall web interface.
From a LAN client which is using m0n0wall as default gateway I can ping the OPT1 IP address (172.18.67.252) but I can't ping the 172.18.67.254 host.
No log is shown on the firewall logs.

Could you help me to found the problem?

Thank you very much!
Goodbye

[hoba]

First, this is pfSense and not m0n0wall  :P
Second, I assume the clients at OPT are using another default gateway that doesn't have a route back to your LAN subnet vie the pfSenses OPT IP. Masquerading would fix that but could cause other trouble on the other hand. Adding a route at the OPT's clients default gateway would be the "cleaner" solution imo. If you reall wan't to NAT enable advanced outbound NAT at Firewall>NAT and add a mapping for LAN to OPT with OPT IP of the pfSense there.