Advice needed for server/home network setup

I have looked around but have not found much that helps with my current setup. I'm looking for some ideas as to the best way to do the following:
I would like to have one computer (linux) on the network open to the outside (connect using FTP, HTTP and/or SSH) and my other two machines behind my firewall. I also have to connect to the internet by dial up (unfortunately). So what I would like is something like the one linux box on the outside - but this one would also then have to share my internet connection, right? And then have the other two connected to my router (behind it's firewall). This is a setup that I have not worked with before, as any server that I have previously setup has only been open to my home network. But I would now like to have access to that from the outside while keeping the other machines "safe" - can someone help with the design behind and what I need to look into to get this to work the way I want?
Thanks in advance.

The easiest way is to setup your linux server as a firewall server running NAT on the outside interface and only allowing connections into your network via port forwarding to the other servers, deny all other services.

on the reverse side, is what you are asking to do. you could setup your linux server as a NAT firewall and have a second firewall on the inside interface this would give you a DMZ affect, at this point you would only allow access into your network from the DMZ using the inside IPaddress of your linux server using port forwarding. (keep in mind NO double NATing) so you would have a second router/firewall connecting your inside linux to your internal network.