Input Interface Incorrect = No firewall rules applied

[DiegoS]

Hello, this is my configuration:

[ISP]------>{eth1(ext)(ip:83.5X.XX.XX)}ZENTYAL{eth0(int)(ip:192.168.2.8}<------[CLIENT(ip:192.168.2.201)]

In Firewall rules for internal networks:
    Source: 192.168.2.201
    Destination: Any
    Service: Any
    ACCEPT

But there is no connecting between client&zentyal o client&externalIP. I look at firewall LOG and I see this:
   Input interface: eth1  <--- I don't understand
   Output interface: eth1 ó vacio
   Source: 192.168.2.201
   Destination: 192.168.2.8  ó  8.8.8.8  ó  other
   Protocol: Any
   Source & Destination Port: Any
   Decisión: DROP

I think that the problem is zentyal identify 192.168.2.201 conections (connected to eth0.internal) as external connection and then the firewall executes external rules.

¿I don't know which how Zentyal indentify incoming conecctions?
Can I look any log for helping me?

Thanks