Until recently, I had a large block of static IP addresses for my home network, which made server setups easy. But I also had fairly low upstream DSL speeds. In order to get faster upstream, I switched providers to Speakeasy. So far I’m very impressed with their service — no limits on reasonable connection sharing within households, and no limits on what kinds of servers you can run. The 768kbps upstream I purchased is going to be perfect for moderate domain hosting from home. I was able to buy an extra static IP from Speakeasy online for a few bucks and have it become immediately available — very cool. But during setup of the new network I hit a snag.
I have five machines on the home network, one of which is going to be a public web/mail server. The server needed to be on the public/static IP, while the other four machines needed to be on 192.168.x DHCP addresses. I couldn’t figure out how to configure the LinkSys BEFSR41 to enable both the Class C and the public networks simultaneously.
The answer was not in the user manual, nor was it on the LinkSys web site. But a friend had been through the same situation and had the situation down cold. The trick is to place a hub inline before the router. So rather than running from the DSL modem to the router and from there to the server and the workstations, run from the modem to a standard hub’s “Crossover” or “Uplink” port. The server can then be connected to one of the hub’s other ports. Another free port on the hub can be run into the LinkSys router’s WAN port. The workstations are connected to the router’s ethernet/hub ports (note that using the Uplink port on the LinkSys will disable port #1, so you’ll need to leave it empty.
As for machine configuration, the workstations can now be set up to use the router as their DHCP server, presumably at 192.168.1.1. Meanwhile, the server gets configured to use its static IP. Rather than looking to the LinkSys router, it uses the DSL remote gateway address, just as the router does.
Of course, the server does not benefit from the firewall features of the router, and so becomes responsible for its own security. Another firewall of some sort needs to be deployed. But it is absolutely possible to run a mix of static/external and dynamic/internal IPs on a home network with a DSL gateway.