hi,

sorry for my bad english

I need to build a lan to lan vpn
I bought 2 router ER7206
to carry out tests I connected them directly with a network cable
The connection is successful.
To install the routers in production I have to place them behind a gateway router.

(side A)
Network (A)
    ER7206 Router (A)
         Internet router (A)
         ..

(side B)
         Internet router (B)
    ER7206 Router (B)
Network (B)

Which port do I need to redirect for the router to be seen from the outside? I hope I was clear.