Yeah, you shouldn't have to have the Firewall turned off.

OK- Direct from the setup in my Linksys BEFSR41 Router/ 4 port Switch:

Under DHCP: DHCP Server Enabled, Starting IP- 100, Number of users 155. (The Router has some issues releasing IP's if the machines don't shut down properly, so I have a lot of IP's allocated.)

Advanced>Dynamic Routing: Working Mode: Gateway TX/RX: Disabled, DMZ Host: Disabled, or set to 0.

Everything else is set to the default settings, or is specific to my ISP. And this setup allows me to have multiple machines on the same server, or on different servers with my Cable service.
I HATE EZBOARD!!!