ADSL Modem behind Zentyal gateway

[alfonsor]

Hi all

usually, in other router OSes, to access the modem behind the gateway, a virtual interface is created on the WAN and a NAT rule is added;

after I finished installing Zentyal as a gateway with a WAN port connected to an ADSL modem, I can't find any way (in the web GUI) to assign a virtual ip address to the WAN interface.

Any suggestion?

Thanks in advance