sundance-communications.com/forum Forums VOIP Phones & IP PBX Networking SBC DSL modem

I have a ADSL modem (Efficient Networks Speedstream 5100) from SBC that I wanted to use to replace a customer's very old ADSL modem that has some problems. The old DSL modem supports a switched hub with 12-15 PCs on the network (not all at once).
I tested the Speedstream 5100, which has only DSL port in and one Ethernet port out, in my office before taking it to my customer's premise. My ISP is Covad, but I hooked it up and it worked fine, the only difference being a slightly different IP address in the gateways (DSL routers).One is 198.168.1.1 and the other's is 192.168.0.1. I just had to log into my ISP and authenticate through the new Speedstream gateway, leaving the PC on DHCP (auto IP address). The PC assumed a new IP on the new 0.1 network after the ISP login and rebooting the PC.
My PC even continued to work fine after connecting a 5 port Linksys 10/100 network hub to the Speedstream.

However, as soon as I connected a second PC to the hub, everything froze, and I could not get on the 'net at all. I rebooted the second PC but the only way it would work was solo.
I believe it would work if I configured the second PC manually with an 0.1 static IP address such as 192.168.0.102. But, I am sure the customer would not appreciate having to do this manually.

I see no reason why this won't work, unless some proprietary measures exist in conjunction with the Speedstream and SBC, such as inputting a modem access code.

Is my reasoning correct?
Is anyone familiar with a way to get past this limitation of one PC on the Speedstream 5100?

A DSL modem is just that - add a switch(hub) to it and you can create a small network. However DHCP is not going to work because the DSL provider is only going to give you one IP address and only one computer will work. Otherwise it doesn't know which computer to route the traffic to. They need a $50 firewall/switch and give each computer a private static IP address and the switch/firewall will be the gateway. You can set the switch/firewall up as a DHCP server and that will also work without addressing static ip's.
The old 5100 modem appears has some kind of built in DHCP (supports broadband sharing up to 255 addresses). Look into Linksys or DLink firewall/router and that should fix it.

Thanks for jarring my brain! Of course my hub wouldn't support the second computer, it needs the router to generate a range of IP addresses to assign. Makes sense to me.

Thanks for the help!