My network:
ETH1: 10.10.xx.xx
ETH2: 192.168.xx.xx

ETH2 in connected to a firewall that forwards ip's 192.168.xx.xx to access a 10.20.xx.xx network
I want to access 10.20.xx.xx network from a PC on ETH1 network.
From my pc i can access the firewall on 192.168.xx.xx and now i need to masquerade my PC IP to be forward to 10.20.xx.xx network

Any help appreciated