D-Link wifi router connected to DSL SpeedStream 5200 modem

SOURCE: speedstream 4100 does not work with router

you can't.
when the item name as modem/router. it means the main function is modem with added router function.
you can't connect 2 router/modem together. both need access to the internet and IPS for it function correctly.
however, you can connect 1 modem and one router.

SOURCE: connecting a Linksys Cable/DSL Router to a speedstream modem

I have a steps by step guide on how you setup the router.

1. First you need to connect the device together. You need to connect your cable modem to the internet port on the back of the router, and the computer should go to one of the 4-port on the router labeled Ethernet (1, 2, 3, 4).
2. Then turn on the modem first, wait for the lights to stabilize before powering on the Linksys router.

3. If the internet is still not working; we will need to adjust a setting on the router setup page. To access the setup page of the router you need to open your internet explorer or Firefox on the computer that is hardwired directly to the router. In the address bar of your browser (Internet Explorer or Firefox) type http://192.168.1.1/ and hit enter or click Go. It will ask you for a username and password. Just type "admin" for the password field and there is no username. If you have ran the setup CD prior to this, then use the password that you have set when were running the setup CD.



4. Once you are in the setup page of your router make sure that the Internet Connection Type is set to Automatic Configuration DHCP, then click the save the settings button at the bottom of the page. After saving the settings, click the sub tab at the very top of the page that says MAC Address Clone. Set it to enable and click the button that will say Clone or Clone your PC's MAC and save the settings again.
5. After doing step 4, do a power cycle. Power cycle is done by turning of the router, modem and computer. Leave them off for a minute, tuned them back on in this order. Modem first wait for the lights to stabilize, then the router wait until the power light become solid. Then turn on the computer. This will get you online through the router.


Check if this will help get the router online.