Have an ethernet cable through the roof from a routermodem in 1st floor. It assigns an IP to my dreambox (DHCP) - the rest of my devices are connected via wireless...

But I have two questions:

1) - how can I set up server using cable (not wireless) that can be reached via internet? Can I add another router with DHCP? I have not physical access to the routermodem in 1st floor

2) - how can I hook up a server that cannot be reached from internet - only on the local home-network.