Using a router and a switch

[LFE]

I want to connect a switch directly to my modem, then connect the router to one of the switch's ports and a computer to the other in order to isolate that computer from the router, as shown below.

Will this work? Will the router and the computers connected to it be hindered in any way other than not being able to communicate with the computer plugged directly into the switch? Will the computer plugged directly into the switch face any problems that it wouldn't if it was plugged directly into the modem?

 

[Dngrsone]

If the router has a built-in firewall, then it will definitely protect the computers downstream from the other computer, though they may be able to request data from that computer.

I have a hardware firewall built from an old P4 computer and running Smoothwall Express, which is a free firewall OS. It allows for a RED+GREEN+ORANGE configuration where the RED LAN port is the internet, the GREEN port goes to your protected LAN and the ORANGE port handles an internet-accessible server. The GREEN LAN is fully protected and can't access the ORANGE and vice versa without being specifically allowed by the administrator.

 

[PvilleStang]

The issue here would be your public IP. Does your modem have NAT turned on on it? In other words, does the modem pass on a public IP to the router / computer, or does it assign a private IP? If it's passing on the public IP, then you will need to have multiple Public IP's available for your use, else this configuration will not work. Your other option is to configure a DMZ in your router and place the computer in a DMZ configured port. This is essentially what your configuration is trying to accomplish.